Bibliography
Short communications
N.K. Awadhwal and D.F. Yule
Dr Awadhwal is Agricultural Engineer, Resource Management Program, International Crops Research Institute for the Semi-Arid Tropics (ICRISAT), Po Patancheru, Andhra Pradesh 502 324, India. The address of Dr Yule, former principal sod scientist with ICRISAT is Queensland Department of Primary Industries PO Box 6014, Rockhampton, 4702 Queensland, Australia.
A range of implements have been developed at ICRISAT for farmers in the semi-arid tropics. They include: Agribar II, used for various tillage operations and which can be fitted with a four-row planter, and simple T-bar bullock-drawn implements for making broadbeds, applying fertilizer, sowing and interrow cultivation; three different models of crust-breaker, covering one row, two rows and a metre-wide strip, to enhance the emergence of seedlings through the soil crust; a twin spinning-disc knapsack-sprayer for low-growing crops; a groundnut digger for hard soil, with chisel points to assist penetration; and a donkey-drawn cultivator-cum-seeder for sowing pearl millet and sorghum in hills and for interrow weeding on light-textured soils.
The objective of developing these agricultural implements has been to enhance the efficiency of farm inputs and operations while paying special attention to the better use of human resources and animal traction, a major source of power in the semi-arid tropics. The broadbed-and-furrow (BBF) system has been successfully tested to increase crop production in the semi-arid tropics (Virmani, Willey and Reddy, 1981). Farmers normally do not have access to implements suitable for making broadbeds and furrows, nor for subsequent operations. Wheeled tool carriers are ideal for this purpose (Awadhwal, Takenaga and Bansal, 1987) but are too expensive for many farmers. A range of simple bullock-drawn implements was developed to enable farmers to form a BBF system easily and to carry out subsequent field operations. Tools have also been developed to facilitate specific tasks such as breaking soil crusts to improve seedling emergence, spraying chemicals on short crops (for example, groundout and chickpea), and digging groundnut in hard soil where blade-type diggers cannot penetrate to the desired depth. A donkey-drawn, low-cost implement suitable for farmers in the African semi-arid tropics was also developed for sowing and speedy weeding operations on light-textured soils.
AGRIBAR-II
This is an improved version of the Agribar. It is lighter, its tool bar is easier to lift and it can be fitted with a four-row mechanical planter. It can be fitted with a plough for primary tillage and with a blade harrow or duckfoot sweeps for preparation of seed-beds. For shaping broadbeds, ridgers and a chain are used. A wide range of crops (groundnut, chickpea, pigeonpea, maize, sorghum, pearl millet and safflower) can be sown at desired spacing if appropriate seed-metering plates are used with the planter (Fig. 1). Fertilizer can be applied in a band, either separately or during planting, with the help of a low-cost hand-metering device. Interrow cultivation can be carried out with duckfoot sweeps and blade harrows. A 15 cm plough, pulled by a pair of medium-sized bullocks (300 -kg each) would cover about 0.2 ha in a six-hour day. However, a 150 cm cultivator would cover about 2 ha in a day.
T-BAR BULLOCK-DRAWN IMPLEMENTS
The central component common to these implements is a T-bar made from either iron or wood. Standard C-clamps are used to attach implements to the iron T-bar, whereas specially designed clamps are used for attaching tools to the wooden T-bar. A range of operations can be carried out using the implements described below.
Broadbed former. Two ridgers are attached to the T-bar with adjustable spacing up to 1.5 m. The ridgers make two 30 cm parallel furrows on each side of a broadbed. A chain is attached behind the ridgers to smooth the top of the broadbed (Fig. 2).
Broadbed former with fertilizer attachment. Four furrow openers and a wooden divider bowl for manual metering of fertilizer are attached to the T-bar of the broadbed former. This enables broadbeds and rows to be made and fertilizer to be applied all in one operation (Fig. 3).
Planter. A four-row planter, developed for groundnut, is mounted on the T-bar along with four furrow openers and a pair of wheels to control the depth of seed placement and facilitate transport of the implement. Press wheels are attached to the furrow openers to compact the seeded rows (Fig. 4). However, for sowing in dry soil a chain can be used in place of press wheels to cover the sown rows. A low-cost hand metering device can be attached to the T-bar in place of the planter for sowing small-seeded crops such as sorghum and pearl millet. However, use of the hand metering device is not recommended for sowing large-seeded crops such as groundnut and maize.
Interrow weeding attachment. Three duckfoot sweeps are attached to the T-bar of the broadbed former and used for interrow weeding. The sweeps cultivate the interrow zone in the crop while the ridgers remove weeds from the furrows and deepen them (Fig. 5).
These implements can be operated using a pair of medium-sized bullocks (300 kg each). Field tests indicate that the average field capacity of each implement is about 0.25 ha per hour and the draught required is in the range of 50 to 70 kg.
CRUST-BREAKER
The poor emergence of seedlings through a soil crust is common in sandy and loamy soils of the arid and semiarid regions. Soil crust must be wetted frequently or mechanically broken to promote the emergence of seedlings. Breaking the crust with a hand-tool such as a sickle can require 200 work hours per hectare (Awadhwal, 1988).
A manually operated single-row crust-breaker with tandem rollers was developed to break soil crusts over seeded rows. It covers a 15 cm strip and is suitable for crust-breaking operations on ridges and on flat land. A manually operated crust-breaker was also developed to cover two rows in one operation. It consists of two inclined roller units. Spacing between the rollers could be adjusted to match the row spacings. Multiple units of either the inclined or tandem roller crust-breakers can be attached to a tool bar pulled by a pair of oxen or a small tractor (Awadhwal and Thierstein, 1983). An animal-drawn crust-breaker with a pair of inclined rollers covering a metre-wide strip has also been developed (Fig. 6). It can cover 1 ha in about three hours. In field tests these implements broke the crust completely, damaged less than 1 percent of the crop seedlings and enhanced the emergence of pearl millet and sorghum seedlings to levels achievable under non-crusted conditions.
SPINNING-DISC KNAPSACK-SPRAYER
A twin spinning-disc knapsack-sprayer for short crops such as groundnut, chickpea and mung bean combines features of the conventional knapsack-sprayer and the hand-held spinning-disc ULV applicator (Fig. 7). It consists of a 10 1 chemical tank fitted to a tubular frame. Two spinning-disc applicators, placed on a boom, are energized by a 6 V rechargeable battery, mounted under the chemical tank. The sprayer is carried on the back of the operator and the position of the boom can be adjusted to suit various crop heights. The empty sprayer weighs approximately 9 kg.
Field trials conducted for the application of pesticides on groundout, chickpea and mung bean indicated that the spinning-disc knapsack-sprayer performed as well as the conventional knapsack-sprayer. It covered a 3 m swath, required only 151 of water and about 90 minutes to spray 1 ha, whereas the conventional knapsack-sprayer required more than 4001 of water and 20 work hours to spray the same area (Awadhwal et al., 1990a).
The sprayer is designed to allow the operator to walk ahead of the spray, which reduces the risk of the operator's exposure to chemicals compared with a portable single spinning-disc sprayer. The risk of exposure can be further reduced if a polythene sheet is suspended from the sprayer frame or is worn as an apron to protect the legs of the operator. In addition, the operator must follow the rules for safe handling of agricultural chemicals, including the wearing of protective clothing, such as a face mask and gloves, when handling and mixing the concentrated pesticides. Spraying should be done only when there is little wind, and the operator should walk in such a way that the wind blows at an angle of at least 30° across his path (Awadhwal and Takenaga, 1989).
Donkey-drawn cultivator - Cultivateur tiré par un âne - Cultivador tirado por un asno
GROUNDNUT DIGGER
Groundnut grown in hard soil is not easy to harvest manually and the existing lifting implements, mainly blade types, cannot penetrate to the desired depth and do not work satisfactorily. For these reasons, a new type of digger was developed. The digger bottom has two shares inclined toward each other at 120°, and there are chisel points for penetration into hard soil (Fig. 8). A single digger attached to a draw-pole can be pulled by a pair of bullocks and two or more diggers can be pulled by a tractor. A single digger covers a 60 cm strip or two rows and has an average field capacity of about 0.04 ha per hour. It requires about 100 kg pull. Field tests showed that in a dry and hard Alfisol, where a blade digger failed to penetrate to the desired depth and left more than 25 percent of pods in the soil, the new digger worked well. The harvesting losses were about 5 percent, comparable to losses incurred during manual lifting of groundnut in moist soil (Awadhwal and Smith, 1989).
DONKEY-DRAWN CULTIVATOR-CUM-SEEDER
A low-cost cultivator-cum-seeder, to be pulled by a donkey, was designed and made in Mali. Its construction is simple and it can be made with local materials. It consists of a wooden mainframe on which three duckfoot tines or the seeder attachment (furrow-openers or seed-hopper) and a gauge wheel are attached with the help of specially designed clamps. The position of the duckfoot tines or furrow-openers and the wheel can be adjusted with respect to the frame, which helps in controlling the depth of cultivation or seeding and facilitates transport of the implement. It can be hitched to a donkey with the harness used for donkey carts (Awadhwal et al., 1990b).
The seeder attachment consists of a seed-hopper and gravity-fed seed-metering device of the stationary-opening type. The size of the metering hole controls the seeding rate and can be selected according to the size and quality of seed. A shutter is provided at the bottom of the hopper to halt the dropping of seeds when desired. A manually operated agitator is also provided in the seed-box to maintain a steady flow of seeds through the metering device. The furrow-openers have a trap and release mechanism that keeps the bottom end of the furrow opener closed. Seeds dropped from the hopper pass through plastic tubes and accumulate in the furrow-opener. Actuation of the release mechanism allows the seeds to fall in hills. The actuator is a lever attached to the gauge wheel and operates twice for each complete turn of the wheel.
The donkey-drawn cultivator was tested for interrow weeding in pearl millet and maize crops. Its draught requirement on a sandy soil was about 32 kg for a 45 cm strip and its field capacity was about 0.1 ha per hour. The two-row seeder was successfully tested for sowing pearl millet and sorghum in hills. The average spacing between two consecutive hills in each row was 42 cm and the number of seeds per hill was 15 and five for pearl millet and sorghum, respectively. Spacing between rows is adjustable up to 90 cm.
CONCLUSIONS
Agribar II is a simple, lightweight and versatile tool carrier with wheels that can perform all the field operations required to adopt improved crop production practices in the semi-arid tropics.
The T-bar implements constitute a simple end affordable option for farmers adopting the BBF system and the improved cultural crop production practices that accompany it.
The spinning-disc knapsack-sprayer requires less water, labour and time for spraying than other conventional equipment and is especially suited to low-growing crops. The groundnut digger allows successful harvesting in difficult and hard-soil conditions where existing blade implements fail, while the donkey-drawn cultivator-cum-seeder is a simple and low-cost implement which is suitable for light soils and can perform fast and timely seeding and weeding operations, thereby helping to increase crop production in the African semi-arid tropics.
An important consideration is that the design of these implements is simple so they can be constructed in small workshops with locally available materials.
Awadhwal, N.K. 1988. Development of an animal-drawn inclined roller crust breaker. Indian J. Agric. Sci., 58(2): 87-90.
Awadhwal, N.K., Ranga Rao, G.V., Wightman, J.A., McDonald, D. & Takenaga, T. 1990a. A comparison of hand-held pesticide sprayers for the control of groundnut pests in India. Trop. Pest Manage. (in press).
Awadhwal, N.K., Shetty, S.V.R., Niangado, O. & Traore, M.B. 1990b. Development and testing of a donkey-drawn cultivator-cum-seeder. Agric. Mechanization in Asia, Africa and Lat. Amer. (in press)
Awadhwal, N.K. & Smith, G.D. 1989. New implements for crop production in the semi-arid tropics. Inf: Bull. No. 27. Patancheru, India, ICRISAT.
Awadhwal, N.K. & Takenaga, T. 1989. Development of a twin spinning-disc sprayer. J. of Agric. Eng. (ISAE), 26: 207-210.
Awadhwal, N.K., Takenaga, T. & Bansal, R.K. 1987. Development of improved agricultural implements at ICRISAT. Agric. Mechanization in Asia, Africa and Lat. Amer., 18(3): 21-25.
Awadhwal, N.K. & Thierstein, G.E. 1983. Development of a rolling type soil-crust breaker. Agric. Mechanization in Asia, Africa and Lat. Amer., 14(4): 31-34.
Virmani, S.M., Willey, R.W. & Reddy, M.S. 1981. Problems, prospects, and technology for increasing cereal and pulse production from deep black soils. In Improving the management of India's deep black soils, p. 21-36. Patancheru, India, ICRISAT.
