Intermittent slope level ditch
Technique to pave gravel on the sloping lands for soil and water conservation
Method of planting trees on terrace risers
Amorpha fruticosa - a good tree species for soil and water conservation
A good species of herb for soil and water conservation
Method of building level strips of land by contour plowing
Covering crops with colored plastic film for increasing agriculture production
Good way to preserve agro-plastic film
4 Compiled by Wen Chuqiang, Shaanxi Provincial Bureau of Water Resources.
Advantages of the intermittent slope level ditch
Southern China farming technology for soil and water conservation
Shaanxi Province is located in the loess plateau mountain area. Soil erosion is very serious here. With a long history of erosion control practices, the local people have found that the intermittent slope level ditch is very useful for erosion control and land utilization. It has all the advantages of intermittent bench terraces, silting dam (locally called Yudiba), and fish-scale pits. It helps to intercept sediment, store water and at the same time increases fertility.
On slopes below 25°, the ditches are constructed 13 m apart along the contour,. The distance between the ditches is narrowed on slopes more than 25°. A ditch of 2 m width and 30 cm depth is first excavated and disposed on the inner side (upper slope); then on the outer side the earth is excavated to a depth of 1 m and the excavated material is disposed on the lower side for a ridge. The ridge should be 0.7 m higher than the original slope surface with a bottom width of 1 m and top width of 0.5 m. The earth should then be rammed. Finally the excavated surface soil is refilled in to the ditch. The refilling should be 60 cm deep. A fast growing, economical tree should be planted where the earth has been refilled at a distance of 5 m from each other. Grasses and other cash crops can grow under the tree. In each hectare of slope land an estimated 750 m long ditches can be constructed.
Effectively controls soil and water loss
Improve forest and grass growth
Low labor and other costs
An area with 750 m/ha of constructed ditches can hold over 900 m3 soil and water each time. Even a 100 mm rain can not cause any soil and water loss. The slope gradually turned into bench terraces with the natural scouring and yearly land preparation and maintenance.
The refilled surface soil brings the fertility to normal top soil level, stores water and conserves soil. This raises the survival rate and growth rate of trees and grasses.
The constructed ditches are not only favorable for the presently growing crops but also for the preparation of future transformation of slope land into forestland or grassland.
On an average, each hectare of sloping land needs only less than 150 labor days and 75 Yuan (9 U.S. dollars) for tree seedling or grass seeds. Also the technique is very simple for the farmers.
The limitations of above ditches are that they needs lot of labor, consume much land and can reduce productivity in the first 2-3 years.
5 Compiled by Chen Fayang, Nanchang Professional College of Water Resources.
Contour cultivation on terraces
Ditch and ridge tillage
Semi-dry rice farming system
Multiple crop rotation
Minimum tillage and mulching system
Contour strip inter-cropping system
Grassland strip rotation system
Some of the agronomic and cultural practices developed by the people in Southern China are given here.
Contour cultivation on terraces is practiced on a large scale for soil and water conservation. It has the capacity to retard runoff, increase infiltration of rainfall and conserve soil and water.
Ditch tillage for preserving soil fertility
Contour ridge tillage
This is a technology used in mountainous areas of south China. People plough the sloping lands into contour ditches or into ridged farmland. This increases surface roughness to retard and store runoff, which benefits the growth of crops. The main patterns used in south China are given below.
The sloping land is excavated into ditches with width and depth along the contour as required for the row spacing of crops or trees. The top soil is put back with base fertilizer into the ditch.
In this type of tillage a ditch or ridge along sloping land contour is constructed to shorten the slope length and change the direction of runoff flow for the purpose of storing water, preventing scouring and combating drought and soil erosion.
This technology is widely used in the steep and arid sloping land. Pits of needed size are excavated along contour. The excavated top soil is disposed on the upper side of the slope and kept for refilling. More sub-surface soil is excavated and disposed on the lower side of the slope to form a half-circle ridge for storing water and preventing soil erosion. Then, the stored top soil on the upper side is refilled in the excavated pits along with base fertilizers. The excavated pits between upper and lower part are staggered in order to shorten slope runoff line, increase capacity for storing water and enough space for crop growth.
In this system the large paddy fields are changed into ridged and ditched fields to store water in the ditches and transplant rice seedling on the ridges. The advantage of this system is that soil erosion is reduced effectively and the yield of paddy rice increased.
Three crops in a year are grown in south China. It is also called the multiple crop rotation system. For instance, wheat-maize-sweet potato or wheat-yellow bean-sweet potato are grown. It has the advantage of conserving soil and water and increasing crop yield. It makes full use of climatic resources, increases the area for photosynthesis, and prolongs the duration of surface cover.
The characteristic of this system is that the farmland is not ploughed after harvesting the previous crop. Ditches are excavated in rows with fixed spacing for broadcasting. The crop residues between ditches are retained and the previous crop straws or leaves or green manure are used as mulch to cover the newly planted crop. This system has the advantages of reducing soil erosion, reducing loss of organic matter and increasing crop yield.
This system is suitable for sloping lands in south China especially with slopes below 25°.
Grassland strips in rotation with crops can effectively control soil erosion, intercept runoff, increase infiltration of soil, improve water quality, and increase crop yield on the sloping lands. The nitrogen fixing grassland rotated with crops will improve soil fertility and structure.
6 Compiled by Mr. Yang Guoqiang of the Jr. of Soil and water conservation, Henan, Zhengzhou, China.
Gravel-cover farming is a non-tillage technology used for a long time by people of Gansu Province. Gansu Province is located in the semi-arid and arid region with low rainfall and lack of water resources for irrigation. This is a typical rainfed farming system.
In this technique a certain thickness of gravel is paved on the surface soil of the sloping land to store water, reduce evaporation, preserve fertility and reduce soil temperature, sanitation and soil loss.
By this technique, the requirements of water for crop growth can be basically met even under semi-arid and arid climatic conditions without irrigation. Since, the rainfall is generally concentrated in July, August and September, agriculture production is not guaranteed without irrigation. However, by paving gravel in a scattered manner on the surface of sloping lands, soil and water are preserved which can assure a harvest, increase crop yields, increase infiltration, reduce evaporation, temperature and salinization and prevent erosion. The example below illustrates the technique.
The sloping land is first ploughed once and the soil raked after the fall season. Then 75, 000 kg of organic matter for melon production as well as 150 kg of urea and 300 kg of ammonium calcium in each hectare are applied as base fertilizer. Pits are dug in rows along contour according to the row spacing of melon. The pits should be marked so that the gravel can be put around. Then between rows, some vegetables such as pepper or eggplant can be inter-cropped. Finally, a layer of gravel in 5 cm thickness can be paved on the remaining sloping land. The pits can be used for growing melon during the right season. After the harvest of melon, the second crop, for instance, maize or bean can be grown without tillage.
The gravel-covered farmland can be paved once and used for 15 to 40 years without tillage.
7 Compiled by Mr. Zhao Jingyong of the Jr. of Soil and water Conservation, China.
Tree species, which are suitable for planting by inserting them on terrace risers, are used. Strong 1-3 year old seedlings with thickness of 0.5-2.0 cm should be selected and cut into strips of 20-30 cm length. A 3 cm diameter, 60 cm long sharp wood is used to make hole on the terrace risers with a spacing of (0.2m-0.50m) × (0.5m-1.0m). The selected tree stripes are then inserted and the whole is filled back with wet soil.
The terrace riser plantation stabilizes terraces and generates income from trees but is limited by rainfall conditions.
This species is found in reasons with 1,000 m AMSL. It is widely distributed in northeast China, north China, Guangdong, Yuannan and Guangxi Provinces. It has a well developed root system, is resistant to drought, and requires cold and wet conditions to grow and can survive on saline and infertile soils, seriously eroded gullies in both dry and humid climates. It is of high economic value as it is used for weaving, fodder, fuel wood, manure etc. It retards runoff and conserves soil.
Buffalogourd (Cucurbita foetidissima) is a kind of perennial herb of the gourd family with perennial roots. It can survive 30-40 years. The plant promises high oil bearing herbal fruits from the very first year to the end and tuber crop underground. It is therefore a kind of economic plant with multiple applications, high adaptability, readily cultivated on barren mountains and floodplains, which are otherwise not arable. An annual intensive farming and fallow cycle is used. Bringing the plant to mountainous areas in north
China, which is extremely dry and sparsely vegetated, may be rewarding in conservation of soil and water, while at the same time increasing the income of local people by the sale of herb.
8 Compiled by Yui Peicheng and Li Yunsheng, Agriculture Research Institute, Chifeng, Inner Mongolia.
Sloping lands can be changed in level stripes by contour plowing in about 5 year period. The ridges formed by this method in between two strips can be further reinforced by planting bushes, fodder grass or medicinal plants on them. This adds to more economic benefits.
For Inner Mongolia region to develop level strips in the sloping lands below 10° contour plow the lands. On the lower side, the height can increase by 20-24 cm and on the higher side the height can decrease by 20-24 cm. The slope becomes gradual after plowing several times. Experience shows that a 7 m wide belt needs to be contour ploughed 3-4 times. A 10 m level land needs to be ploughed 10 times.
Crops like rice seedling and carrot grow faster if covered by a red plastic film. Red color strengthens the absorption capacity of the leaves and makes the seedling grow healthy which in turn improves the harvest.
If a yellow plastic film is used to cover bean, lettuce, celery and cucumber, they will grow well and increase the yield by 50-100%. Farmers can get good harvest and prolong the marketing supply period to get economic benefit.
If the temperature gradient of the green house is to be adjusted, silver colored film should be used.
There are 3 indigenous methods to preserve and save agro-plastic film
1. Put the clean plastic film in a plastic bag and bind the mouth of the bag and keep in a cool and damp place. This way the film can be preserved for 2 years.
2. Put the plastic film in a big jar with a weight on it, then add water to the jar until the film is submerged and cover it. This way the film can be preserved for 4 years.
3. Put the clean plastic film in a plastic bag and store it in a 30 cm deep hollow or a cellar. This way the film can be preserved for 3 years.