SATrends Issue 35                                                                                                                   October 2003

  • Why donít they use fertilizer?
  • Grey to green - literally
  • Eye in the sky
  • Baselines surveys in Tanzania
  • 1. Why donít they use fertilizer?

    For many years, yields from smallholder African agriculture have been falling. Soils were nutrient-poor to begin with, and have been further depleted by continuous cereal cropping. The solution? Use fertilizers to replace lost nutrients. But few smallholders use fertilizer, especially in drought-prone areas - precisely those areas where the soils are most heavily depleted.

    Why are farmers reluctant to use fertilizer? Several explanations are frequently reported: too expensive, not easily available, not available in convenient pack sizes... However, another school of thought says farmers, consciously or otherwise, examine rates of return on their investments. They are not investing in soil fertility simply because they have better investment options.

    Consider fertilizer use in terms of risks and returns. In areas with high, reliable rainfall, purchasing a few bags of ammonium nitrate will almost always yield a profit. But in a drought-prone area, itís much riskier - if the rains fail the crop will fail too, even if fertilizer is used. So the farmer loses not only his crop but his fertilizer investment.

    Pigeonpea intercropped with maize

    ICRISAT economists evaluated the risk-return tradeoffs for several different soil fertility technologies in Zimbabwe. These included cereal-legume rotations, intercrops, manure and fertilizer at various dosages and combinations, as well as various types of manure treatment. Field experiments were conducted for two seasons at three pilot sites jointly by the national research and extension Services, ICRISAT, CIMMYT, the Tropical Soil Biology and Fertility (TSBF) Programme, and most important, the farmers themselves.

    Interestingly, the numbers depend not only on rainfall and economic status but also on gender. Male- and female-headed households show significant differences in fertilizer use. So do two types of female-headed households, the de facto (husband away, works in town) and de jure (no husband - widows, divorcees).

    For each group in each area, the most appropriate investment strategies were identified. For example, for a male-headed household with access to labor and draft animals in a low-rainfall area, the most profitable technologies are: maize with 9 kg/ha of nitrogen applied, maize with kraal manure plus 18 kg/ha nitrogen, maize-groundnut rotation, and maize-cowpea rotation. For de facto female-headed households with fewer natural resource endowments but better access to cash from the husbandís remittances, the best option was maize with kraal manure plus 18 kg N/ha.

    In general, for the poorest families, the best options to improve soil fertility were legume rotations and intercrops. Legumes improve soil fertility, and provide a high-protein diet supplement that substantially improves family nutrition. Perhaps most important, they are valuable cash crops, widely traded in most communities.

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    2. Grey to green - literally

    Rajasthan in western India. Images that come to mind are those of camels stretching their legs over desert sand, hot, dry and rocky land, thirsty underfed livestock, and villagers wearing brilliant colors to offset their drab surroundings. This is just imagination one might argue, but it takes even more imagination to picture this landscape with green meadows, shady trees, and cool spots where the Nilgai (blue bull) rests. Such a place is evolving as we speak, thanks to the efforts of ICRISAT and a consortium of partners (Sir Dorabji Tata Trust, the NGO Bharatiya Agro Industries Foundation, the Government of Rajasthan, various agencies within the Indian Council of Agricultural Research, and the National Remote Sensing Agency), who have converted hard, rocky, stony, unyielding land into useful pastures.

    Before rehabilitation

    The consortium and people from nearby villages took an area of 18 hectares of common village land in the district of Bundi in eastern Rajasthan, and using soil and water conservation measures such as continuous contour trenches, 200 staggered trenches, 293 mini-percolation tanks, and six gully plugs, brought it to a level hospitable to useful plants. They planted 25,000 Jatropha curcas and Pongamia pinnata trees (in time the mature seeds of these trees will produce diesel supplements), Stylosanthes grass and local Dhaman grass to hold the mud bunds together, Glyricidia trees to improve soil nitrogen, and commercially viable plants such as neem, Ziziphus, and Acacia for income generation in this area.

    The Green Island taking shape

    The project started in June 2002 and will run for five years (the pictures are therefore of very young plants). Contrasted with the nearby denuded common village land, this 'Green Island' will provide the valuable fodder for cattle and regular income to the Panchayat (local village government).

    The benefits of the active participation by the community and the willing support from the Rajasthan Government and other consortium partners were evident at the recently-held ICRISAT Farmers Day in that part of the country, where the rehabilitated common ground was a big showpiece. The project is also being effected in a nearby 5 ha plot of land, and the partners expect to spread this technology to more and more degraded areas in and around the State by the end of the project term.

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    3. Eye in the sky

    You can't afford a satellite to take pictures of your farm? Try flying a kite. It may sound crazy, but this is exactly what ICRISAT scientists in Niamey, Niger, are doing - and it works!

    Following a May 2001 visit to INRACI, an educational institute specializing in electronics and cinema in Brussels, ICRISAT scientists Philippe Delfosse and Bruno Gerard, both Belgians, presented their purchase department with a wish list for additional electronic equipment for improved aerial photography. The system was developed by Olivier Hendricks under the supervision of Jean Morren, with a former ICRISAT scientist, Charles Bielders (now at the University of Louvain) and Delfosse as promoters, and Gerard acts as advisor. Funds for the project were provided by the Peanut Clump Virus (PCV) Project, which is funded by the Belgium government. Says Delfosse, 'The system is simply amazing!'

    Hereís how it works. A digital camera is fixed to a balloon or a kite along with video equipment, and sent up to an altitude of about 1000 m. The equipment includes a GPS and a full remote control system to orientate the camera. Altogether the kit weighs less than 2 kg.

    The operator on the ground views the image on a 14-inch color monitor. A read-out on the screen shows the status of the battery, the number of shots taken, the exposure and the aperture. On the remote control board, a small LCD displays either the altitude and position or the status of the batteries of the video sender. The same remote operates the servos that orient the camera and turn the video sender on or off.

    A birdís perspective of a farmerís groundnut field featuring large peanut clump virus patches) and millet fields (low millet population).]

    The scientists spent around $2500 for everything - not too much for a research tool that provides high-resolution images of the area being photographed. Results are immediate, and the quality of the digital photography is 5 million pixels per inch!

    Olivier came to Sadorť to fine-tune the system on the ground. He brought the electronics and Delfosse built most of the frame. Scientists evaluated the system in Maradi, a town 500 km east of Niamey, for a week, and for two days in Fakara, one of our benchmark sites 50 km east of Niamey. An immediate use is to estimate losses to peanut clump virus in this area.

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    4. Baselines surveys in Tanzania

    Tanzania, one of ICRISATís four target countries in southern Africa, is a large country with substantial semi-arid areas and increasing poverty and hunger in many regions. ICRISAT and its partners are working to boost smallholder agriculture there by testing and promoting new technologies that can improve productivity and incomes.

    In most development work the first step is to establish a baseline. This serves two functions. First, it establishes the starting point, so that future progress can be measured. Second, it helps better understand the local farming system, identify the key problems, and tailor the research agenda accordingly.

    ICRISAT economists recently completed a baseline survey in Tanzania. Four districts were covered: Dodoma Rural, Kondoa, Singida Rural and Babati. The first three lie in the dry Central Plateau, where sorghum and pearl millet are the dominant crops. Babati, in the Arusha region of northern Tanzania, is the countryís most important pigeonpea area.

    The farming system is fairly diverse: sorghum, pearl millet, maize, plus a variety of legumes (pigeonpea, groundnut, cowpea, beans), and a few cash crops like sunflower and sesame. ICRISAT recently introduced a new sorghum/pigeonpea intercropping system, which is steadily growing more popular. First, the research team held informal discussions with farmers on cropping systems, resource requirements, constraints, and so on. This information was supplemented through interviews with scientists, extension officers and rural traders. This was followed by a formal survey covering a wide range of issues.

    Farmer and surveyor

    The survey found that farmers were generally aware of new technologies. For example, 80% of the farmers surveyed were aware of improved sorghum varieties, over 80% were aware of the new sorghum-pigeonpea intercropping system, and 67% knew that fertilizer application could improve yields. But thereís a big difference between being aware of a new technology and actually adopting it. Only 50% of farmers grew improved sorghum varieties, 40% had planted a sorghum-pigeonpea intercrop, and less than 8% had ever used fertilizer!

    Why is adoption so poor? The survey found many reasons, but the most important was lack of information. Almost every farmer who had not adopted the intercropping technology cited lack of information - he had heard about the new system, but didnít know too much about it and wasnít confident enough to try it. Various reasons were cited for non-adoption of other technologies (lack of seed, cost of fertilizer, too much labor).

    This information is priceless. With a clearer understanding of both agro-ecological and socioeconomic factors, ICRISAT and its partners can improve R&D targeting, making new technologies more relevant and more valuable to Tanzaniaís smallholder farmers.

    For more information contact