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3) Forage and feeding of milk cow:

Stall feeding is normally carried out in the dairy on fish farms. The feeding of milk cow should be performed on the scientific basis; therefore, the formula of daily feeds and feeding plan must be worked out according to the standard which includes nutrient components of the forage and nutritional requirements of the animal. These standards vary in different countries, each has its own general standard. For instance, U.S.A. has NRC system.

Feeding Standard for Milk Cow (Daily)

Oat Unit Standard
Body weight (kg)Oat forage unit (kg)Digestible crude protein (kg)Ca (g)P (g)

Milk Net Energy Unit Standard (NND)

Body weight (kg)Dry materials (kg)NNDDigestible crude protein (g)Ca (g)P (g)Carotene (g)Vitamin A (I.U.)

Rearing Standard (Daily Nutritional Requirements for the Production of 1 kg of milk)

Oat unit standardMilk net energy unit (NND)
Milk fat Index
Oat unitDigestible crude protein
Dry Materials
NNDDigestible crude protein

These are the minimum standards, and 10–15% can be added in practice. As the body weight of the primiparous lactating cow is still increasing, their standard should be 20% higher.

If the proposed milk production is over 6,000 kilograms, usually they are fed with the feed for the weaned multiparous cow with daily milk production of 15 kilograms.

Daily portion of forage for the milk cow is given according to the milk production (the amount of milk produced and its fat content index). The feeding standard can be calculated out according to the nutritional requirements of daily milk production plus the average body weight of the milk cow (counted as 600 kilograms). Then take the nutritional requirements of the feeding standard for milk cow for reference, calculate out the total daily nutritional requirements. The physiological characteristics of different stages of the milk cow should also be considered in the calculation, e.g., pregnancy, etc. The price of the feeds and palatableness should also be considered. The forage of the milk cow is mainly green and coarse feeds. In winter or hay season, cows are fed on one kilogram of dry grass and stalk of the crops, 3–4 kilograms of silage or 5–7 kilograms of root tubers for every 100 kilograms of body weight. 8–10 kilograms of green grass are given to every 100 kilograms of body weight in grass growing season. One kilograms of mixed fine forage is given for production of every 2.5–3 kilograms of milk. The ratio of fine forage mixture is 30% cake type feedstuffs (if chicken manure are used, only 15% can be added), grain feedstuffs (barley, corn) about 40%, bran 10–15%, by-products of processing 10%, minerals, salts and fish meal 10%. The above ratio is only for reference. The nutritional components of different forages can be calculated from the nutrients table, and also the amount should be adjusted according to the needs of the milk cow. The production of mixed forage developed very quickly in the recent two decades. Forage manufacturers use computors to calculate the needs of the milk cow, and mix the feeds automatically. They can produce and supply mixed whole forage.

Milk cow is fed three times daily with fixed amount at fixed time, adopting the method of small amount but frequent supply during feeding, usually fine forage given first, followed by fodders, and then water. The forage must be fresh. Iron nails and wires must be removed if there is any in it. Milk production can increase by 10–15% if sufficient amount of water is drunk, by milk cow. They should have sufficient exercises. The whole body of the cow is brushed before milking, dry brushing in winter, and washing and brushing in summer. Cow shed should be cleansed frequently in order to keep the shed and playground clean and sanitary. Cow manure and urine are washed directly through manure ditches into fishponds. 5–20% bleaching powder emulsion or 5% cresol is used for the sterilization, which should be performed at least monthly.

Within 4–5 days after parturition, the milk in the breast of the high yielding milk cow should not all be squeezed out, only 2 kg of milk each time. One third of milk is milked out on the second day and then the amount could gradually be increased. All milk could be squeezed out on the 4th day. Dry fine grass, not forage with much juice and fine food, are given to the weak cow as its main food within 3 days after delivery. The milk production gradually increases 10–15 days after delivery, and reaches its peak of lactation.

Fine quality grass, sufficient forage and sufficient amount of water should be guaranteed at this stage to meet the nutritional demands of lactation. The milk production gradually decreases 3 months after delivery, and weaning starts 60 days before next delivery. 10 days before weaning, reduce the amount of fine feeds, green fodders and juicy forage and times of milkings as well. Do milking every other day or every 3–4 days. Stop milking when the production drops to 4–5 kilograms.

4) Milking technique and storage of fresh milk:

Milking can be conducted manually or electrically. Integrated fish farms usually don't have large numbers of milk cow, therefore, manual milking is preferred. Wash the udder with 50°C warm water and then thoroughly massage the udder. Milking is performed by first massage of two nipples at a time. The first and second runs of milk are collected in a special container, and should not be mixed with normal milk in the milk pail. When a large part of the milk is milked out, the udder should be massaged again in all areas, and finally massage should be carried out the third time at the end of milking until all the milk is out.

The milk collected by manual milking should be filtered by gauze to remove hairs, dust, fecal materials and other impurities. It is to be cooled quick ly and preserved in a cool place. The milk should be thoroughly sterilized and covered tightly and transported to milk-collecting station as quick as possible.

7. Artificial Breeding and Utilization of Earthworm

Earthworm is good food for fowl and fish. Fresh earthworm contains 8–10% protein, while dry earthworm up to 56–66%. Its effective energy is 2920 Cal. per kg. Its nutritional value is equal to that of fish meal. The reproductive ability of earthworm is very strong, and it can multiply 200 times within one year under normal conditions. If good care is taken it can multiply 1000 times. No special equipment and fodders are required for the breeding. The fermented cow dung, pig manure, weeds and rank grass from the integrated fish farm mixed with proper amount of silt are good fodders for the earthworm. Large-scale propagation of earthworm can not only improve the soil, but also increase the productivity of the crops and improve the environment. Artificial breeding of earthworm is now advocated and propagated in our country. Some of integrated fish farms take earthworm breeding as one of their animal raising. Earthworm can serve as protein feeds for both poultry and pigs or fish. The results are very promising in enhancing yields.


Fertilizers and feeds are considered to be two of the basic conditions to strive for a high yield of fish. All fertilizers are used primarily to propagate natural organisms for fish to eat. various kinds of forage grasses, beans, grains, melons and vegetables, aquatic plants, etc. are also good foods for fish. To establish an integrated fish farm needs certain amount of forage land and land for forestry, animal husbandry and side-line production as well, which are all directly beneficial to fish farming.

Crop production on an integrated fish farm means the utilization of pond dykes, river banks, corner areas, etc. and the forage field. Cultivation of grains, beans, pasture grasses, melons and vegetables, fruit and mulberries should be rationally practised in accordance with the needs of fish and the growing seasons of different crops. Furthermore, water surface at the edge of rivers & lakes in the vicinity of the fish farm can be utilized to cultivate aquatic plants so that high quality forage will be available at every season of the year. This kind of forage and silage can directly be used not only for breeding fish, but for rearing domestic fowls and animals or fertilizing water to grow plankton for fish.

1. Pasture Grasses

1) Perennial ryograss (Lolium pereme)

It is a perennial plant belonging to the Gramineae family. It has such features as quick growth, high yield, rich in nutrition, easy to cultivate, low cost and strong adaptability. Its yield may reach 5–10 tons per mu. It is a good food for Grass carp, Chinese bream and Wuchang fish. Ryegrass cultivation can provide fresh food for fish in early spring, thereby, enabling them to break their fast ahead of season.

  1. Seeding and transplanting

    Ryegrass is a tardy plant which grows even in the shade and likes moisture. Seeding is usually done at the end of September. Land should be prepared by applying 1,000–1,250 kg/mu of human feces as the base manure, or splash a layer of river silt over it, and upturn the soil by deep tilling, and then pulverise and smooth the soil. The amount of seed for broadcast sowing is 2–2.5 kg/mu. If the weather is dry after sowing, sprinkling is necessary and this should be continued till the complete emergence of seedlings. Then give another dressing of human feces of the same amount as the first application.

    Transplantation is usually conducted at the end of October and early November. When seedlings grow to a height of 12–15 cm, they are pulled out to be transplanted in a field that has already been tilled and splashed with a layer of pond silt as base fertiliser. The leaves of seedlings should be cut half to ensure quick establishment. The spacing is 18 × 18 cm or 21 × 21 cm, and 6–7 seedlings are planted in one bunch. After transplanting, apply night soil in 1:3 dilution (night soil 1, water 3) to facilitate establishment and growth.

  2. Field management

    Weeding: In order to enhance the growth of transplants, all weeds have to be eradicated. Weeding should be repeated now and then after transplanting.

    Watering: Seedling plots and transplant fields should be kept moist and watering is necessary in prolonged fine weather.

    Fertilizer treatment: Usually one application of nitrogenous fertilizers is given before the initial cropping. Later on, organic manures should be dressed at a rate of 250–300 kg/mu after every harvest. The result is better if soil could be loosened and fertilizer applied the very day when it is mowed. Some inorganic fertilizers can also be used.

  3. Harvesting

    When ryegrass grows to a height of 30–60cm, cut them near the ground to serve as fish feeds. At this time, this grass is tender and so every bit of it is consumed. Thus, the utilization rate of feed is high. Besides, ryegrass grows fast and has a high power of tillering after cutting. Generally speaking, when air temperature is low from October to next Feb., the growth of ryegrass is retarded, and only one or two outtings could be performed. From March to May, harvesting can be done once every 20 days or so. Be sure that the second and third cuttings are made closely to the ground, leaving stubbles only 2–3 cm high so as to increase tillering, harvesting and promote its quality.

  4. Reservation of seeds

    English ryegrass begins to shoot, bear ears, and flower in April, and seeds can be collected in early June. Since seeds do not ripen at the same time and will fall to the ground easily, so when the colour of the ears turns yellow, collection should be done in time to prevent seed loss. The yield is about 50 kg/mu. Plots reserved for seed production should not be cropped as green fodder.

2) Sudan grass (Sorghum sudanese)

Sudan grass is an annual plant belonging to the genus Sorglum andropogon of the Graminese family. It can thrive in soils of different fertility; however, the fertile clayish soil is better. The yielding is about 10 tons per mu.

Sudan grass has such features as the ability to withstand dryness and fertileness, rapid regeneration, high reproductivity, strong adaptability, high yield, superior quality and easy cultivation. It is a high-yielding crop in summer and autumn and so is suitable for subsequent cultivation of ryegrass to provide high quality fresh food for Grass carp, Bream and Wuchang fish from spring right through autumn.

  1. Seeding and transplanting

    Sudan grass likes damp environment but dreads frost. Seeding is usually done when soil temperature above 10°C. The optimum temperature for germination is 20–30°C.

    Strip drilling is suitable for Sudan grass which is primarily out for green fodder. Row spacing is 20–30 cm and the depth of seeding 3–4 cm. Then, it should be mulched with a layer of plant ash 1 cm thick. The amount of seeds used for dense drilling is about 2 kg/mu. Besides this, dibbling or nursery seeding can also be practised. Plant spacing for dibbles is 18 cm. Each bunch takes about 10 seeds. When young seedlings are 12 cm high, they are ready for transplanting. The plants are spaced at about 18 × 18 cm with 4–5 seedings each bunch.

    Prior to tilling and sowing, apply a layer of pond silt over the field as base fertilizer to be upturned into the soil, and then level and smooth the soil.

  2. Field management

    Emergence of seedlings is completed 7–8 days after seeding. Budding takes place in about 70–80 days, and flowering in 80–90 days. The growth period is 100–120 days. Weeding should be done regularly. In prolonged fine weather, sprinkling should be given, especially during the seedling period. It is better to loosen the soil and apply fertilizer after every cutting. The method of dressing and the amount of fertilizer used are the same as those for ryegrass.

  3. Harvesting

    When Sudan grass grows to a height of 60 cm, harvesting is feasible. The cutting should leave a stubble of about 10 cm high, otherwise, tillering, regeneration and the yield will be affected. From mid May to Aug., harvesting can be done every 15 days or so. Growth slows down around September and death comes with the appearance of frost.

3) Bunch grass Symphytum peregroinum

This species is a perennial plant belonging to the Borraginaceae family. The region of origin is Iran-Transcaucasic. It is usually set in early spring yielding 7–9 tons per mu in the first year to be followed by 10–12 tons in the second year, and it may reach 15 tons. Fresh stems and leaves of this grass are tender and juicy, nutritious with high protein content. According to calculations from dry matter, it contains 22–25% crude protein, 4–6% crude fat, 7–13% crude fibre and 38–40% non-nitrogenous extracts. So it is an excellent green fodder rich in protein.

This grass has a well-developed root system with vigorous growth, and has strong adaptability to environmental conditions. It is susceptible to few pests and is easy to grow and propagate with a high survival rate. Its underground portion can withstand adverse temperature conditions ranging from -40°C to 37.8°C. Besides, it is resistant to draught and disease.

  1. Seedling cultivation and setting

    The organs of this plant above the ground like leaves, pedicles, rhizome buds, and those under the soil like rhizomes and roots can all be used as asexual materials for seedling culture and propagation. The methods of propagation in practice are division of suckers, root cutting, longitudinal cutting of root necks, setting buds divided from root and setting of stalk cuttings, etc. The period for nursery bed breeding is 30–40 days. When seedlings grow to a height of 10–15 cm, they can be transplanted and set at a spacing of 45 × 45 cm with about 2500–2600 plants per mu. In poor soils, increasing the plant population to about 3000 per mu is advisable. In dibbling, bury the plant up to the neck of the root which is the proper depth of setting. After that it should be sufficiently watered.

    This grass is tolerant of a wide range of soil conditions, but a thick layer of sandy soil with good drainage is considered to be the most suitable. Plants can be cultivated on spare spaces around a pigsty and on slopes of pond dykes. This would facilitato management. Land should be deeply tilled, harrowed, smoothed and levelled before setting the plants. It should also be well manured. It plays where is inconvenient broad ridgor with grcoves crossing each other will enable rain water to be drained off readily in rainy season.

  2. Field management

    Dressing should be done once before the grass turns green in early spring. The amount of pig manure applied is roughly 2500 kg per mu. To the seedlings that are just set, measures should be taken to loosen soil and weed the field in time. After establishment, dress again to invigorate the settings and promote the development of roots. During the growing period, fertilise the soil each time after harvest, and also before overwintering. The last dressing will ensure stout plants to tide over the cold months. When the weather is dry and hot, sprinkling should be done timely while attention ought to be paid to draining in the rainy season. Water logging will cause the root to rot. This grass is quite resistant to pests and no serious case has been noted so far. However, in its seedling stage, cutworm attacks often occur and measures should be taken to control it.

  3. Harvesting

    When this plant begins to bud and flower in early and mid may, harvesting can be done. Cut the stems above the ground, leaving stubbles of about 6 cm to germinate anew. After that, harvesting is done at intervals of about 35 days. Thus, a year gives about 5 or 6 cuttings. In general, one planting would do for 8–10 years. Upon arrival of autumn, this grass will no longer bud and flower. The proper time for harvesting depends on the amount and colour of the foliage. Usually, no more cropping is done towards late October so as to retain the year's final coat of leaves for over-wintering. The crop is highly resistant to cold, and growth ceases only with the coming of frost which makes it gradually wither and die. However, the roots under the soil can even survive severe winter temperature as low as -40°C. In order to make a full use of land, inter-cropping can be done after auturn for other fodder crops.

2. Beans

1) Soybean (Blycine max) (G. soja) (Soja max)

The soybean is an annual plant belonging to the sub-family Papilinaceae of the Leguminousae family, the native plant of China.

The yield of soybean is generally 80–130 kg/mu. Soybean seeds contain 30–40% protein, 20–24% fat and about 30% carbohydrates. Besides these, there are several kinds of minerals and vitamins, and its nutritive value is very high. When ground and fed to fish fry, it forms an excellent food.

From seeding to maturity, the life of a soybean plant undergoes a few growth stages like the germination-seedling stage, the third trueleaf stage. The whole growing period is about 120–140 days. The length of time from germination to blossoming varies with variety. Generally speaking, that for the early ripening varieties is 34–43 days, that for intermediate varieties 40–60 days, that for late varieties 50–60 days and that for very late varieties 63–84 days. They are tolerant to a wide range of soil conditions but soil layers that are thick and rich in calcium and humus with good drainage (pH value 5–8) are more suitable. However, they will not grow in soils where pH value exceeds 9.6 or is below 3.9.

  1. Seeding

    When the seed of soybean absorbs water of 100–150% of its own dry weight, it will commence to germinate if air temperature is 10–20°C, and at the same time, there is sufficient supply of oxygen. Under suitable soil moisture conditions, the seed will absorb enough water within one day. Seedlings will grow rapidly when air temperature averages 20–25°C in the day time and not below 15–17°C at night. Seeding time for spring and summer soybeans is late March to early April and June 1 to 20 respectively. The amount of seeds required for seeding is 6–7.5 kg/mu. Seeds should be selected by winnowing, screening and choosing prior to seeding. The emergence of soybean cotyledons is relatively difficult, and so it is necessary to keep the soil loose. Besides, the germination of soybean requires ample moisture. Before seeding, the soil should be upturned and smoothed to preserve soil moisture and fertilizer. The method of seeding adopted is dibbling. Commonly, plant spacing used is 15 × 18 cm or 18 × 18 cm. One mu may have 15,000–20,000 dibbles, each of which takes 2–3 seeds. After seeding, they are mulched with a thin layer of plant ash or fine soil to facilitate emergence.

  2. Field management

    Fertilizer treatment: For every 50 kg of soybean produced, it is necessary to apply 2.8 kg of nitrogen, 5 kg of phosphoric acid, and 6.5 kg of potassium oxide. At the initial stage when nodules have not yet been formed at the root portion of the seedling or the action of the root nodules are rather weak, growth is slow. In order to raise soybean production, it is necessary to apply an appropriate amount of nitrogenous fertilizer and a large amount of phosphorus and potassium. In addition to applying sufficient base manure, seed-mulching manure is also feasible, i.e., to use a small amount of high quality fertilizer like decomposed barnyard manure, or high quality compost mixed with plant ash, or superphosphate to mulch the seeds seeded. Later on, by judging growth conditions, apply an appropriate amount of ammonium sulphate at a rate of 2.5–5 kg/mu during the seedling stage and 7.5–10 kg/mu during the flowering stage.

    Checking, replanting and thinning for evenness: when soybean seedlings have uniformly emerged, a check should be made. Dibbles without seedling have to be replanted. In order to enable seedlings to grow stoutly and evenly, thinning should be done when a pair of true leaves have appeared.

    Inter-row cultivation for weeding in combination with hilling: As is common, after seedlings are established, shallow hoeing for weeds in conjunction with thinning should be done thrice. From flowering to the swelling up of pods, soya bean plants are in utter need of water. If draught is to continue, serious reduction of yield will result. In places where conditions permit, rational irrigation will increase production to an appreciable extent. At the stage when pods are ripening, pulling all weeds out will better inter-plant ventilation and the penetration of sunlight into the foliage cover, thereby enhancing earlier ripening and ensure a bumper crop. At the same time, the work of prevention of such pests as the soybean aphids and pod borers, and bean hawkmoths, and the weed, dodder Cuscuta (love vine), should not be overlooked.

  3. Harvesting

    The mature stage for spring & summer-sown soybean crops fall on mid or late July, and early or Mid October respectively. When two-thirds of the foliage have turned yellow and fallen and the majority of the stems and pods appear dark brown with seeds separated from the inner walls of the pods, when the beans are already half-dried and quite hard and are of their original colour, and when you're shaking the plant some rattling sound comes from the pods, It can be ascertained that the time of harvesting has come. All attempts should be made to gather in the crop within a week's time. Transport the harvest to the drying yard where it should be turned over and over to be sunned for a few days until it is thoroughly dry, and then separated from the pods on fine weather. After tossing the beans into the air to remove all impurities, and drying, it could be stored when their water content is below 13.5%, while those used as seeds the water content should be below 12% to ensure long storage.

3. Grains

1) Barley

Barley is an annual plant belonging to the genus Hordeum of the Gramineae family.

The yield of barley is about 200–300 kg/mu. Apart from being a food grain, barley is an important material used for brewing boer, producing alcohol and making maltose. Its straw is good for weaving The growing period for barley is about 190 days. Its lowest germination temperature is 1–2°C. The optimum temperature for growth is around 20°C. It bears ears in early and mid April with a milk stage of about 10 days to be normally followed by a wary ripe stage of 6–7 days.

  1. seeding

    Seeding of barley is generally done in late October to mid November at a rate of 15–18 kg of seeds per mu. It can be broadcast or strip drilled. Its root system is mainly distributed within 15–18 cm of the cultivated surface layer. So secondary tillage should be done carefully with the “3-ditch” pattern of drainage. Seeding should be shallow and even. For producing every 50 kg of barley, it is necessary to fertilize the soil with 1.5 kg of nitrogen, 0.62 kg of phosphorus and 1.15 kg of potassium. Base manure to be applied is 6,000–7,500 kg/mu of grassdecomposed pond silt or pigsty manure 2,500–3,000 kg/mu. For the intarmediate soil layer, 15–20 kg of ammonium sulphate and 25 kg of calciua superphosphate per mu should be used with 3,000–4,000 kg of seed-Mulching manure per mu.

  2. Field management

    Early stage field management: If seeding is followed by draught, measures should be taken timely to ensure total emergence of seeds evenly, and fertilizer be applied at the first-leaf stage, using 500 kg of night soil diluted with 3,000–3,500 kg of water per mu, or 10–12.5 kg of ammonium sulphate diluted with water for splashing over the surface. Another way is to use mainly organic manure made up of about 5,000 kg diluted silt mixed with 30–40 kg of dissolved ammonia water per mu, or applying 1,500 kg of pigsty waste and then splash a layer of thin river silt weighting 5,000 kg. Inter-row cultivation may be done 2 to 3 times. Cholraluron may be used for weeding on barley fields.

    Intermediate stage field management: Be prepared for application of fertilizer for reviving of seedling. In general, this is done by applying 7.5–10 kg of ammonium sulphate per mu in early February, or 20 kg of ammonia water dilution or 1,000 kg of night soil for splashing. Ditches have to be cleared to better drainage and prevent dampness. Towards the end of the month, be sure to make a dressing of about 12.5 kg of ammonium sulphate per mu to promote growth and the bearing of ears.

    Late stage management: Be sure to do the work of disease prevention and pest control. Spray 90% trichlorfon in 1:1000 dilution to control army worms; 40% dimethoate emulsion 1:2000–3000 for aphids, and 0.2– -0.3 kg of carbendazol diluted with 75–100 kg of water for red mold and powdery mildew.

  3. Harvesting

    Barley is ripe by mid or late May. Harvesting should be done at the waxy ripe stage.

2) Corn (Zea mays)

Corn is an annual plant belonging to the genus Zea of the Gramineae family. Its nutritive value is very high. The yield is generally 250–300 kg/mu and so it is one of high-yielding crops and a good fodder. Its grain contains 8.5% protein, 4.3% fat and 73% carbohydrates. So 50 kg of corn is equivalent to 67.5 kg of oats, or 60 kg of sorghum or 65 kg of barley in nutrition. The nutritive value of corn stalk is usually more than double that of stalks or stems of other crops. Fresh stems and leaves harvested after the shooting of the phalanxes or before waxy ripe are green and juicy. Their nutritive value is very high. No matter whether they are used as green fodder or silage, they are good substitutes for fine feeds. Therefore, the successful cultivation of corn plays an important role in developing livestock farming.

Corn thrives well in warm climates. The lowest temperature required for its germination is 10–12°C. It is a crop that needs short solar irradiance. In its young seedling stage, the amount of water it requires occupies 22.7% of the total needed for growth; the middle stage of growth calls for 44.5% while the late stage 32.8%. Soil suitable for its cultivation should be rich in organic material and well-drained, or of the sandy loam type. For producing every 50 kg of corn grain, the crop would take up 1.24--1.95 kg of nitrogen, 0.68–0.91 kg of phosphorus, and 1.96–2.07 kg of potassium from the soil. According to the length of its growing period, the varieties of corn to be planted can be classified into:early varieties (80–95 days), intermediate varieties (96–115 days) and late varieties (116–150 days). According to the sowing season, corn varieties are divided into spring corn, summer corn, autumn corn and winter corn.

  1. Seeding

    Before seeding, careful selection of seeds, examination of their germination rate and seed preparation through sunning, immersing and mixing with chemicals should be done in order to achieve the full germination, evenness of growth and get seedlings of vigorous growth. Spring corn can be seeded when soil temperature is above 10–12°C. To enable seedlings to have a longer period of growth, attempts should be made to sow the seeds as early as possible. Summer-and-autumnsown corn should be seeded as soon as the preceding crop is harvested. Seeding is usually done by drilling or dibbling. Seeding rate for drilling is 2.5–4 kg per mu; for dibbling 2–3.5 kg. Seeding depth is 3–5 cm. Seeding density for late varieties is 2,000–3,000 plants per mu, for the intermediate 2,500–4,000 and for the early ones 3,000–5,000. When it's cultivated for fodder (silage or fresh), the density of planting may be heavier by about 20% compared with those just mentioned above. There are many ways of planting corn. Tilling depth can be 21–24 cm, and ample organic manures should be applied before land is tilled. In places where ridge cultivation is practised, special action should be taken to prevent draught and to preserve moisture for the top soil. In water logging or poorly drained areas, bedding cultivation should be adopted.

    Application of base manure serves as principal source of nutrition for plants. Barnyard manure, livestock manure and compost prepared from the decomposition of stems and stalks which are all organic manures rich in nitrogen, phosphorus and potassium, are the best base fertilizer for corn.

  2. Field management

    After the emergence of the seedlings from the soil, thinning should be done timely. Get rid of the weak seedlings and leave the strong ones so as to ensure their evenness and vitality. Quick-acting fertilizers such as night soil, ammonium, sulphate, urea, potassium sulphate and plant ash are applied as top dressing to promote growth during the three stages - the shooting up of stalks, the impregnation of ears and phalanxing.

  3. Harvesting

    After pollination, corn will be fully ripe in about 50–65 days. The higher the air temperature, the faster it will ripen. The leaves on the stem will turn yellow, the wrappers of the corn-cob will dry and wither, and the grains on the cob will look bright when it is fully ripe. It indicates the harvesting time comes.

3. Sweet potatoes (Ipomoea batatas)

Sweet potato is a trailing plant belonging to the Convovulaceae family. The region of origin is tropical America and Caribbean. Its yield is about 1,500– -2,000 kg/mu. The tuber contains 20–27% starch, 2.3% protein, 0.2% fat and also multi-vitamins. Besides its use as food, it is also a fine high-yielding forage crop. Its tubers, vines and all residues after processing can be used as fodder. Its tender and juicy vines and leaves form a good fresh fodder. Its value as a feed is higher than ordinary forage grass. On one hand, sweet potato tubers can be used for feeding pigs and yet on the other hand, pig manure can be used to fertilize pond water. At the same time, its vines and leaves can be cut twice during July and August, yielding 1,000–1,500 kg of fresh vines which can also be served as fresh fish feeds.

From the setting of cuttings to harvesting, the growth period for sweet potato plants is usually 110–160 days. Early tuber-bearing varieties can give a harvest in 80–90 days. The plant likes hot weather but cannot withstand cold.

It will stop growth at a temperature of 15°C and stored tubers will be “frostbitten” even at 9°C. It is a relatively draught resistant crop and will thrive in regions with an annual precipitation of 400 mm.

  1. Seeding and transplanting

    In sweet potato production, most people adopt the tuber-vine-cutting method of propagation. Yield increase is directly proportional to the time the cuttings are set in advance. Spring cuttings should be set from late April to mid May and summer ones in June.

    The density of settings is to be determined by such factors as climate, soil, the amount of fertilizers applied, the characteristics of the sweet potato variety, the length of the growing season and the method of cultivation.

    As the sweet potato is a tuber crop, it needs a deep, loose soil layer for growth. Therefore, land used ought to be ploughed to a depth of 12–15 cm and then banked in ridges for setting the cuttings. To produce every 500 kg of tubers, the vines have to absorb 2 kg of nitrogen, 0.503 kg of phosphorus and 3.1 kg of potassium. The most suitable fertilizer for this crop is a compound fertilizer that contains N.P.K. such as barnyard manures and the compost. The manures that have more potassium like plant ash will give good, conspicuous results in increasing the yield.

  2. Field management

    When roots of sweet potato cuttings are established, a check should be made to have the missing settings replanted. Inter-row cultivation and weeding should be done timely. After dressing and spraying, it is necessary to do tilling and weeding. In principle, inter-row cultivation ought not to damage the root system of the plant. Earth banking is not only of help in preserving soil moisture and preventing the tuber from being exposed, but also in draining water away as the grooves are deepened in the process of ridge banking which is usually done twice during the growth of the vines.

  3. Harvesting

    Harvesting comes when the weather gets cold and frost is approaching; when leaves near the stock have fallen and others turning yellow; when tubers have sufficiently swollen and their water content has reduced. Spring-set crops are harvested at the end of September to early October, while summer-set ones in mid or late October.

4. Melons and Chinese Cabbage

1) Chinese cabbage

Chinese cabbage are biennial vegetables belonging to the genus Brassica of the Cruciferae family. It is the native plant of China.

The nutritive value of Chinese cabbage is very high. According to analysis, the deeper the leaf colour, the higher its nutritive value is. Each 0.5 kilogramme of Chinese cabbage contains 5.5 g of protein, 0.5 g of fat, 10 g of sugar, 2 g of crude fibre, and 4 g of inorganic salt. Besides, there are vitamins, carotenes, and mineral salts. In general, the yield is 1,500– -2,500 kg/mu. It serves as fresh food of high quality for herbivorous fish as well as domestic animals and fowls.

The optimal temperature for the growth of Chinese cabbage is 15–20°C. For seed germination, the optimum temperature is 20–25°C. A proper soil moisture should be maintained. When seedlings are young, nutrition requirements are small. In the middle stage when growth is vigorous, the demand for nutrients increases. Nitrogen is the major one it needs. The soil should be fertile with good moisture retaining properties.

  1. Seeding and transplanting

    Spring seeding: This refers to sowing and transplanting from the beginning of February to the end of May. Chinese cabbage that are directly seeded usually begin cultivation in early February.

    Summer seeding: This refers to sowing and transplanting from early June to the end of August.

    Autumn seeding: This refers to cultivating from early September to the end of October.

    Winter seeding: This refers to cultivating from early November to the end of next January.

    Seed rate: Varieties sown in early spring need 3.5–5 kg of seeds per mu; spring-sown ones usually 1.5–2.5 kg/mu; summer-sown Pakchoi (Brassica chinensis) 2.5–3 kg/mu; summer variety (direct seeding) 0.5–0.75 kg/mu; autumn-sown and transplanted 0.75–1.0 kg/mu; and winter nursery bed-cultivated 2.5–3 kg/mu.

    Method of seeding: Chinese cabbage seeds are sown by broadcast. Thinning, weeding, manuring, spraying and pests control should be done after the emergence of seedlings.

    Field setting: Setting is also known as transplanting. Different cultivation seasons have different requirements on setting. Seedlings for transplantation before August are usually about 25 days old; those transplanted in September, 28–30 days old; those transplanted in October, 32–35 days old; and those for transplantation in November, 35–40 days old.

  2. Field management

    The field management work includes top dressing, sprinkling/watering and disease/insect control.

  3. Harvesting

    The harvesting period of the Chinese cabbage differs a great deal as cultivation methods vary. Young Pakchoi seedlings directly sown in summer can be harvested in 20 days; those cultivated in winter, in 80– –90 days; those transplanted from mid September to the end of the month, in 25–30 days; those transplanted in October, in 40 days; and those transplanted from mid October to early November, in 45 days.

2) Cabbage (Brassica aleracea cv. capitata)

Wild cabbage is a biennial plant belonging to the Cruciferae family. It is the native plant of southern Europe. The variety commonly cultivated in China is the ordinary cabbage. The yield per mu can reach 2,000–4,000 kg. It is rich in nutrition, having proteins, carbohydrates, mineral salts and vitamin C. Besides being edible, it is a very fine fodder for animals.

Wild cabbage, being a biennial just forms the edible globular top in the first year, and it is until the following spring when air temperature is still as low as 2–6°C that it starts to initiate flowering buds and then out to blossom and bear seeds. It adapts itself nicely with good resistance, through the optimum temperature for its growth is 14–20°C. It grows well in fertile soil that can retain moisture effectively with good drainage and easy irrigation. During the stage of formation of the globular top, it needs ample fertilizers and water. Nitrogen claims the largest share of its need though a considerable amount of phosphorus and potassium are also required. Its resistance to disease is good.

  1. Seeding and transplanting

    Cabbage can be planted all the year round. According to harvesting season and cultivation method, it can be divided into three kinds: spring cabbage, summer cabbage and autumn-winter cabbage.

  2. Field management

    Spring grown cabbage usually needs several applications of top dressing before the year ends. Night soil is dressed in 1:2 dilution and the amount to apply is about 1,500 kg/mu, one week after the setting of the seedlings. The second dressing should be given before Jan. 19 to enhance sprouting early in spring. The concentration and amount of manure are the same as the first dressing. The third one is to be applied one month later, and the concentration and amount to dress being 1:1 and 2,000 kg/mu respectively. The fourth dressing depends on the stage of growth, that is, when spring cabbage is forming its globular top in March to early April. The rate of diluted night soil applied is 1,500–2,000 kg/mu to accelerate the growth of the globular top and make it solid. It is necessary to dig drainage grooves in early spring. From the setting of the plants to the closing-up of ridges by their foliage, tilling is conducted in combination with weeding 3–4 times.

    Summer grown cabbage (Brassica broccoli) usually need three dressings within a month. Each dressing calls for 1,500 kg/mu of human feces. The first dressing is given in 1:3 dilution after the set transplants have been established. The second one is dressed 10 days later in 1:1 dilution. Before the formation of the globular top, the third is applied in 2:1 dilution. When the globular top begins to form, no more dressing should be done as it is liable to cause rotting, during the whole process of field growth, chemical fertilizers can also be applied singly like aqueous ammonia in 1:100 dilution 4–5 times at a rate of 25 kg/mu. The soil is generally loosened 2–3 times.

    Autumn grown cabbage generally gets 3–4 dressings, each applying 1,500 kg/mu of night soil but in different concentrations. The first dressing is given 3–4 days after the transplants have been established in 1:3 dilution. Half a month later comes the second in 1:1 dilution. The third is applied before the formation of the globular top in 2:1 dilution.

    The cabbage for over-wintering should not be dressed too heavily in the second and third dressings. In the middle of November, dressing is given to back up globular formation of the top using 2,000 kg/mu in 2:1 dilution.

  3. Harvesting

    Spring grown cabbage are harvested in batches sooner or later from mid April to early June depending on the variety. The yield is 2,500–5,000 kg/mu.

    Summer varieties are seeded in early March and harvested in July-August with yields of 1,500–3,000 kg/mu. Those sown in early May are gathered in August-September with yield of 1,500–2,000 kg/mu. Those seeded in early June are collected in September-October with yield of about 2,300 kg/mu.

3. Squash (C.maschata, Cucurbita maxima, C. melopepo)

The squash is an annual plant belonging to the Cucurbitaceae family. It is the native plant of the tropics.

The squash is a juicy fodder of high yield. It is rich in nutrition containing a lot of carotene as well as vitamin C and glucose. Its stems and leaves can be processed into stalk sugar fodder after drying. Its yield is generally 1,000–2,000 kg/mu.

The optimum temperature for the germination of squash seeds is 25–30°C while the most suitable one for the development of the fruit is 25–27°C. It belongs to the type of crops that need short solar irradiance. It thrives well in a dry, hot environment with a soil moisture of about 50%. A fertile, neutral or slightly acid sandy loam soil is best suited for its growth.

  1. Seeding and transplanting

    Nursery bed seeding period usually falls between mid March and early April. Two kinds of seeding are in general practice: one is bunch planting, the size of planting holes is usually 7.5–9 cm square and 9–12 cm deep. Each hole takes an average of 2–3 seeds after which it is mulched with a layer of nutritive fine soil which ensures them not to be exposed to the air. Spread a thin covering of straw over the bed to serve as shading and to preserve soil moisture, or place a few short bamboo sticks over it and then spread a plastic sheet on them to act as cover for the same effects. Finally, fit up a glass window frame and use mud to seal up the edges of the covering. At night use some straw mats to blanket the whole thing to prevent the loss of heat and accelerate germination.

    The other method is “broadcast” sowing (also known as 2-stage breeding). Over the surface of a dressed bed is spread a layer of plant ash and then cast the seeds evenly on it. After that, use a tiny-hole nozzle sprayer to sprinkle fine droplets over it and then mulch the seeds with a layer of nutritive soil of 2 cm thick. Finally spread a layer of straw over the bed or cover it with a plastic sheet by setting up a glass window for the sheet covering and then seal the nursery bed tight. At night cover it with a straw mat to preserve the heat in it to enhance germination. It's necessary to maintain proper temperature, better ventilation, sufficient sunlight and to control pests in the nursery.

    Setting the transplants: When squash seedlings have grown to a height of 9–12 cm with 2–3 true leaves, they can be transplanted. They are usually set in late April, and intercropping with other vegetable crops.

  2. Field management

    After transplantation, check for missing transplants and reset.

    Dig holes and orientate the plant.

    Hill vines opportunely.

    Control disease and pests.

  3. Harvesting

    Early set squash can be collected 10–15 days after the pistillate flowers have withered. Harvesting in batches at regular intervals commences from the end of July, and large area collection takes place in early and mid August.

5. Aquatic Plants

1) Water peanut or alligator weed (Alternanthera philoxeroides)

The water peanut plant is a perenial plant which is a native plant of Latin America and was introduced into China more than 30 years ago. This plant is a high-yield, easily cultivated aquatic crop and good for both fodder and manure. Surface of lakes, river bends, ditches, and ponds can all be used for float cultivation. It is not difficult to propagate, and relatively easy to over-winter with strong adaptability. The yield of fresh grass can reach 15–25 tons per mu annually - an amount enough to provide 10–15 pigs with silage all the year round. Its stalks and leaves contain 2.49% non-nitrogenous extracts, 2.18% crude protein, 0.18 crude fat, 1.19% of crude fibre, 1.25% ash content, 0.232% calcium and 0.028% phosphorus. It can not only be served either fresh or cooked, but can also be prepared as fermented fodder or dried and ground as fodder for use throughout the year.

Water peanut plants love warm climate, humidity, and sunshine. They also need fertilizer. Although they are not strict about the depth of water on which they thrive, they can grow well in rivers, ditches and ponds which have slow running or stagnant water that is fertile with a depth of 1–1.5 meters. They undergo asexual reproduction through their stalks and vines.

As seedlings can germinate and grow on each and every node, they can propagate very fast.

  1. Time for breeding and propagation

    The growth and reproduction of water peanut plants are very fast. With the exception of the utter heat in summer and the bitter cold in winter, the rest time of the year are fit to make cuttings for transfer and propagation. However, if it is to be introduced into a locality for cultivation from another region, it is best to do so at the beginning of April when the old stalks are starting to germinate or just before they germinate. On the arrival of these introduced cuttings, they should be promptly cast onto the surfaces alloted to the within one or two days with the aim of promoting their early germination for earlier cultivation. Shelter them from wind and sunlight to avoid the risk of being dried. Self-reserved seedlings are best cut for cultivation after new stalks grow to a height of 15–30 cm. Cuttings can float better in this way, thereby, warding off the onslaught of waves.

  2. Method of planting

    Generally, two methods are in practice: Laying ropes and using lattice frames. In places where the flow is little swifter and the water somewhat deeper, the method of laying ropes is adopted to prevent the seedlings from being scattered by the wind. While in stagnant ponds latticed frames are used.

  3. Management

    Fertilizer treatment: In general, water peanut needs no fertilizer. If water is sheer and leaves of seedlings turn yellow at the start or in the process of growing, then it is necessary to give top dressing such as fertile silt mixed with barnyard manure, or to spray diluted nitrogenous fertiliser on time in order to promote growth.

    Weeding: This should be done before planting so as to wipe out all obstacles in growing water peanut. If weeds and moss reappear after cultivation, they ought to be timely wiped out. Moss is generally eradicated manually. If the results are not so good, it is better to spread plant ash or copper sulphate to kill it. This is done in two ways: One is to use 0.2–0.5% copper sulphate solution to kill the moss on them; the other is to crush copper sulphate into small pieces and put them in a small bag hanging on water surfaces densely aggregated by moss. With the gradual dissolution of copper sulphate in surrounding water, moss is killed.

    Pest control: Three-spotted plusia occurs in July to September crawling over and devouring water peanut plants. To control them, use 90% crystalline trichlorfon at a concentration of 0.083 ppm for spraying, after which, 3–5 days have to elapse to allow the chemical to lose its toxicity enough before they can be harvested and fed to livestock. Steps can also be taken to remove a part of them away so that affected erect stalks will bend over and lie on the surface of the water, thereby drowning the pests.

  4. Harvesting

    After planting for 30–40 days with stalks and leaves rearing 20–30 cm above the surface, harvesting can be done, leaving stalks of about 6 cm above water and retaining about 3–4 leaves on them. After that, cuttings can be made every 10 days or so. In July and August, the weather gradually becomes warmer with abundant rainfall. Thus, water is enriched, the growth is fast and so harvesting at shorter intervals is advisable. After every cropping, use a hoe to loosen and separate the seedlings. This will help restore growth through better spacing. Towards the end of October comes the last harvest of the year.

  5. Seedling reservation and over-wintering

    Water peanut plants to be reserved for seeding should be densely cultivated on sunny leeward ponds. Choice should be made of plants whose stalks and leaves look luxuriant, relatively well-seasoned and healthy. Reserves should not be cut for harvest after Frost's Descent. Stalks and leaves of such seedlings should remain 30 cm above the water surface. Thus, when the leaves on the top are frost-hit and wither, they will note: Frost's Descent, 18th solar term, around Oct. 23. naturally fall over and cover up the plants beneath them, thereby, serving as a protective layer which is of help in over-wintering the crop.

2) Water lettuce (Pistia stratiotes)

It is a wild aquatic plant belonging to Araceae family.

The roots of this plant look like a bundle of cotton threads suspended in the water: The stalk is very short and leaves grow in clusters. Each plant has 6–10 leaves arranged in a ring-like fashion. Leaf blades look oval in shape, on both surfaces of which grow velvety hairs. Its flowers are yellow, and the stamens without pedicles grow in symphysis but look protruded, while the pistils are like solitary bulbs of oval with single ovary in which are found several ovules. The fruit is a kind of berry.

Water lettuce plant contains 1.07% crude protein, 0.26% crude fat, and 1.63% carbohydrates. It also contains considerable amount of crude fibre and It can be used as fresh or cooked fodder for pigs. It grows and reproduces very rapidly and the yield is very high, 10–20 tons per mu. At the same time, it has such advantages as less labour, lower cost, no land-use and easy management.

Water lettuce floats on the water and so surfaces of river bends, lakes and ponds, etc. can all be used for propagation. It grows well in places where the water is fertile and stagnant. On running water, its growth is relatively poor. The suitable depth of water for cultivation is 0.7–1.5 m, and the optimum pH value is 6.5–7.5. This crop likes warm weather, and its resistance to cold is poorer than water peanut and water hyacinth, but its endurance to heat is better. Although it can grow in any temperature between 15–40°C, it grows faster when it is 22–35°C. It divides and reproduces the fastest, especially between 30–35°C. If water, fertilizer and sunlight conditions match nicely, each plant can reproduce 50–60 plants within a month. When temperature is above 35°C or below 18°C, it is unable to divide, or just divide a few times. When it is below 10–15°C, it will just maintain its life activities, and when it falls below 5°C, it will perish at once. Its endurance to fertility is very high, and so it demands an ample supply of nitrogenous fertilizer if it is to grow well. If water quality is poor and no fertilizer is applied, it will not thrive well.

  1. Small pond planting in spring

    When air temperature rises above 15°C around mid April, small ponds can be used to plant seed seedlings removed from the nursery beds for preliminary propagation in order to supply sufficient seedlings for extensive planting in summer. When seed seedlings are transferred to ponds be sure that they are getting crowdedly together at one corner of the pond so that they will mutually give support to one another and not move about freely. Every measure has to be taken to prevent filamentous green algae from entangling the seedlings, and to provide such good conditions as fertilizer, air temperature and humidity, and places with still water for their propagation so that general cultivation may commence ahead of season.

  2. Large-scale planting in summer

    When the temperature of the water surface has risen to about 23°C around mid May, the growth and reproduction of water lettuce increases in speed conspicuously. It is necessary to catch hold of this opportunity to expand the cultivation of this crop. The amount of seed seedlings to use on water surface of one mu is 10–20 kg. When planting, it is necessary to use reed stalks, bamboo poles, or tying straw ropes together to form an enclosure to cultivate them inside it so that they may thrive and grow in a colony to speed up reproduction. If the population increase meets with a check, the enclosure should be enlarged gradually to provide more space for growth, and when the seedlings have occupied more than half of the pond surface, the ropes confining them can be removed to let the crop propagate at will. Later on, they can be transferred to other places for cultivation and expansion.

  3. Water surface management

    Fertilizer treatment: Fertilizer is applied 5–7 days after planting. After that, the dressing is done weekly, each time at a rate of 250–300 kg of night soil per mu or pigsty manure diluted 4- to 5-fold to be splashed onto the leaf surface in the evening.

    Prevention and control of weeds: On the initial stage of planting, it is compulsory to eradicate all weeds on the water surface. If filamentous green algae is present, kill it by casting plant ash or spraying 1% lime water or 0.5% copper sulphate.

    Pest control: Use 0.5% 666 powder to spray on the leaves of water lettuce early in the morning when their surface are still wet with dew to control aphids, or use 40% dimethoate emulsion in about 1:2000 dilution for spraying. At the initial stage of the occurrence of yellow wilt, use the Bordeauz mixture of 160- to 200-fold water suspension for spraying to control it. Crop can be harvested for fodder one week after applying chemicals to avoid poisoning of livestock.

    Sprinkling water on leaf surface: In bright summer weather when the day is hot and dry, it is necessary to sprinkle clear water on leaf surfaces 2–3 times at noon to increase humidity and lower air temperature locally, thereby, promoting growth.

  4. Harvesting

    Cropping usually commences from mid or late June. First, divide the crop into several square blocks and then scoop up the plants block by block. The amount to gather depends on growth conditions. Be gentle in making the harvest in order to avoid too much shake-up of the crop. After harvesting, the seedlings should be brush apart so that they are distributed evenly on the water surface to enhance their propogation.

  5. Seedling protection and over-wintering

    From late Oct. to early or mid April, the work of protecting the seedling for over-wintering should not stop until it is entirely frost free. The work is done on the nursery beds. To maintain temperature properly is the prerequisite to the protection of seedlings. Therefore, it is essential to keep the temperature of the wintering nursery above 15°C. In addition, more sunlight and better ventilation will help the crop to overwinter safely.

3) Water hyacinth (Eichhornia crassipes)

It is a perenrial aquatic plant belonging to the Pontederiaceae family. The plant floats on the water, growing out creeping branches from its roots to form new branches. The leaves grow out straight and are either oval or round in shape varying from 2.5–5.0 cm in width. They are smooth and shiny. The petiole bulges out on the lower half like a gall bladder, a spongy interior filled with air. The flower is monopedicle with a sheath in the middle portion and flowers of six petals blossoming on the top in violet and blue. There is a bright yellow spot at the centre of the top petal.

The yield of water hyacinth is very high, reaching 10–16 tons per mu. It is also rich in nutrition. Analysis shows that fresh crops contain 1.9% crude protein, 0.25% crude fat, 1.11% fibre, 2.21% non-nitrogenous extracts. 1.33% ash content and inorganic salts like calcium and phosphorus. Therefore, the planting of water hyacinth is a good way of solving green forage for pigs. This crop likes warmth and humidity and still water or slowly running water. The optimum water depth is 0.3–1 m but the water has to be fertile. Its adaptability is better than water lettuce; especially its endurance to poor fertility is higher. The river bends and ponds that are not fit for planting water lettuce can be used for cultivating spring water hyacinth, and yet produce a considerable amount of forage. Besides this, it is more cold-resistant than water lettuce. As long as temperature remains at 7–10°C. it can safely overwinter.

  1. Planting time

    Water hyacinth is cultivated along the Changjiang River Drainage in early or mid April. When air temperature rises above 13°C and frost is over, the old seedlings that have overwintered start to germinate and sprout. New leaves burst forth with all vigour. This indicates that it is the right time to plant hyacinth.

  2. Method of planting

    Small stagnant ponds of less than 1 mu can be directly seeded with water hyacinth seedlings which may float and grow in it at will, while in large ones or in slightly running water, planting should be done with the help of bamboo frames or by setting up supports and then tying straw ropes to them to enclose an area of the water surface for planting the seedlings within it. When the enclosure is densely populated by them, enlarge it gradually until eventually the supports and ropes are removed. In this way, the crop will not be dispersed by winds and waves, and so it is advantageous to its growth and reproduction. One mu of water surface needs about 4–6 kg of seed seedlings.

  3. Management

    Fertilizer treatment: In fertile ponds, no application of fertilizer is required, but it is necessary to stir the fertile silt at the bottom to enable nutrients to dissolve in the water. If water quality is poor, the plants will be weak and slender, and leaf blades will look yellow. It shows that night soil or animal manure need to be applied to the crop. The dressing is usually done in the vigorous growing season weekly or biweekly.

    Weeding: During the initial stage, the growth of water hyacinth is easily interfered by weeds. So it is necessary to eradicate the aquatic weeds and filamentous green algae. Weeding will cease only when the growth of water hyacinth is vigorous and when seedlings cover up the whole water surface.

    Cropping: When water hyacinth plants are growing luxuriantly and reproducing rapidly after planting for a month or two, harvesting can commence. The amount to gather is about one-fourth of the whole crop or one third at the most. After cropping, it is necessary to brush the seedlings apart for speedy reproduction. In summer, it is possible to gather the harvest once every week, but this interval of cropping depends on the fertility of the water, the growth condition of the crop and air temperature. In Changjing River Drainage, the growth of this plant ceases by the end of October when temperature drops below 10°C and leaves begin to turn yellow. At this moment, seedlings that are of medium size, that look more seasoned and healthy and that are free from diseases and pests are to be chosen for overwintering. The method involves placing a layer of fertile pond silt at the bottom of large vessels or wooden tubs and fill it with water to the 9 cm level. Then put the selected seedlings into it and place the containers in a nursery, the temperature of which is maintained above 7–10°C. The seedlings should be frequently exposed to sunlight and can be placed together with water lettuce seedlings in the same nursery for overwintering.

Fig. 1

Fig. 1. Thermo-electric umbrella for chick nurture

Fig. 2

Fig. 2. Wooden feeding trough

Fig. 3

Fig. 3. Cylindric feeding trough

Fig. 4

Fig. 4. Chain-driven feeding trough

Fig. 5

Fig. 5. A big opening jar with an aluminum plate beneath

Fig. 6

Fig. 6. Chick transportation cage

Fig. 7

Fig. 7. Broiler transportation cage

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