Integrated Soil Water and Nutrient Management Activities in the SADC/ICRISAT Sorghum and Millet Improvement Program

Introduction

There is a crisis in the communal farming areas of Zimbabwe. Nutrient resources in both the cropped areas and the surrounding common property resources are steadily declining (Soil fertility management strategies and practices by smallholder farmers in the semi-arid areas of Zimbabwe. Mapfumo P, and Giller E. 1999. In Press). Nutrients are being lost from the cropped areas, and the grazing and forest areas, through non-sustainable utilization practices and soil erosion. The declining nutrient status means decreasing productive capacity. When combined with an expanding population in these areas, the problem leads to a cycle of deepening poverty. If the trend goes un-checked it may also lead quickly to an ecological disaster, with the potential productivity of the communal areas being completely depleted. Intensive efforts to reverse the trend of declining nutrient status are highly justified, if not imperative.

At the same time, it is clear that farm production levels in the communal areas can be greatly increased, with known technology, and in sustainable ways. On-farm trials by ICRISAT and the Department of Research and Specialist Services (DR&SS) in semi-arid areas of Zimbabwe indicate that grain yields can be increased by 100–200%, simply by using good crop production methods (the right crop varieties, small amounts of fertilizers, timely weeding, etc.). The main difficulty lies in determining how smallholder farmers can actually apply more productive and sustainable systems in ways that are practical, feasible, and profitable within their existing socio-economic and biophysical environment.

To improve their productivity, farmers need knowledge and technology options. But they also need access to input markets, and perhaps most importantly, they need access to reliable output markets. Access to markets provides both the incentives and the rewards for increasing productivity. And the income generated from the scale of farm products is essential for eliminating poverty.

ICRISAT and the SADC/ICRISAT Sorghum and Millet Improvement Program (SMIP) are working with a wide range of public and private sector partners in Zimbabwe and Tanzania to address these issues.

The SADC/ICRISAT SMIP is a SADC regional program that has been funded by the USAID, BMZ/GTZ and the Canadian CIDA, and is being implemented by ICRISAT. The program began in 1984, and initially focused on crop improvement for sorghum and millets. While the program has been very successful in the development of improved varieties (almost 50 improved varieties of sorghum and/or pearl millet have been released by national programs participating in SMIP during the life of the program), the research focus has been changing over time. The fourth and final phase of SMIP began in 1998 and continues to September 2003. For this phase of the program, the focus is on:

• Seed systems to ensure that smallholder farmers have access to seed of improved sorghum and pearl millet varieties;
• Improving productivity, to capitalize on the productive potential of the new varieties, and increase household food security and incomes (while protecting the environment);
• Improved markets for sorghum and pearl millet, as an incentive for increasing productivity and to increase incomes; and
• Regional networking, to ensure that all stakeholders in the region have access to knowledge and information gained through the activities of SMIP.

The work of SMIP is concentrated in four countries in this phase (Botswana, Mozambique, Tanzania, and Zimbabwe). Partners in SMIP activities include the national programs (research, extension, and other government departments), Universities, non-governmental organizations (NGOs), and the private sector. In some cases, bilateral donor aid programs provide supplemental support for the activities of national-level partners, and other international organizations are involved (e.g., the FAO).

The goals and objectives of SMIP are virtually the same as those of ICRISAT. The broad knowledge base, on-going research efforts, and germplasm resources of ICRISAT have contributed, and continue to contribute, directly to the success of the program.

 

Increasing Productivity

The work being done by ICRISAT and SMIP in increasing productivity is the subject of this report. While the work on increasing productivity is considered here alone, in reality it is linked directly with the other efforts in seed systems and improving output markets.

The objectives of this work are to increase the productivity and incomes of smallholder farmers, and to protect the environment. The focus is on integrated soil water and nutrient management (ISWNM). The soil nutrient status is extremely important for the reasons presented in the introduction. Improved soil water management is important because the lack of moisture is so often a limitation to crop productivity in the semi-arid areas, and because if not managed well, erosion can also contribute to major nutrient losses and environmental degradation. In a more positive light, it is known that improved management of these two key resources holds tremendous potential for increasing productivity and incomes at the farm level.

The Program

For both ICRISAT and SMIP, the program targets both the identification/adaptation of improved management options, and the pilot testing of approaches to facilitate adoption of better management systems by smallholder farmers. For the latter, the links with input supply and output-marketing efforts are crucial. Research is being conducted in both Tanzania and Zimbabwe. National research and extension systems are key partners. A range of other interested stakeholders are also involved.

In both countries, work on increasing productivity began with in-depth literature reviews on soil fertility and soil water management research, examination of technology options currently considered to be effective, levels of adoption of recommended practices, and farmer's current production systems in the semi-arid areas. Baseline surveys of farmers' current practices and production constraints were implemented in target research areas. Information generated in the ICRISAT crop growth simulation program helped to guide the choice of input levels to be examined. In addition, discussions were held with research, extension, and NGO personnel, and farmers, to identify technology options that appeared to be practical and effective, and which were of interest to farmers.

In Zimbabwe, interaction with target communities was initiated in the 1998/99 cropping season, and a systematic on-farm, farmer participatory research (FPR) process was launched in the 1999/00-cropping season. The purpose of this process was to test and adapt the range of soil fertility and soil water management options that had been identified in the earlier stages of the program. Technology options that prove successful are to be fed into a subsequent pilot program will attempt to facilitate broad adoption in target areas. Two representative target districts, Tsholotsho and Gwanda South, were selected.

In developing the FPR program within communities, initial village level meetings were held to introduce and discuss the program with community leaders and members. Interested farmers then volunteered to participate. Additional meetings were held with groups of volunteer farmers, to discuss the technology options and methods for conducting the trials. Farmers' input was sought and incorporated in the program as far as possible. The majority of farmers who volunteered to participate were women.

A series of trials were implemented. These included two trial types: Researcher managed trials (RM) and farmer managed trials (FM). The RM trials were designed by researchers to address topics of particular interest to research, and to provide good quantitative data on specific questions. Researchers supervised all field operations, and provided all necessary inputs. Researchers also supervised all data collection activities. For the FM trials, farmers individually selected the technology options they wished to evaluate. For the different options being tested, agreement was reached among farmers on the trial designs and the systems for applying the experimental variables. Farmers individually selected the levels they would apply for all non-experimental variables, and conducted all field operations themselves. Farmers also maintained records of their field operations. Researchers did assist farmers in the harvest data collection. The main cereal crops were sorghum and pearl millet, and the main legume crops were groundnuts, cowpeas, and Bambara groundnuts.

Prior to harvest, field days were held in the two communities where the FPR program was being implemented. Participating farmers identified trials that they felt exemplified the most important lessons emerging from the trials program (some of these were RM trials, and others were FM trials). The farmers implementing the trials then presented their work to visiting community members. 100 to 150 farmers attended field days from the local communities.

After harvest, farmers conducted a joint evaluation of all technology options, by scoring and ranking the various treatments, within trials, according to their own evaluation criteria.

Technology options evaluated in the FPR program in 1999/00 included:

• Modified Tied Ridging, in combination with fertility improvement treatments (modified tied ridging involved using a plough to make furrows between crop rows, and “tying” the furrows with soil every meter or two to trap rain water in the field. The operation was implemented in place of the first weeding);
• The use of farmyard manure (FYM), and combining minimal amounts of FYM and inorganic nitrogen;
• Management systems to improve the quality of FYM;
• The use of legume rotations to improve soil fertility; and
• Seed priming (this is the practice of soaking the seed overnight in water, before planting. The purpose is to improve the rate of emergence. Stand establishment is a common problem in the semi-arid areas).

Rainfall in the 1999/00 season was approximately 100% above normal in the two target research areas in Zimbabwe. This was also the first year of the trials program. Results therefore should be interpreted with caution. None-the-less, there were several results that were of interest. Highlights of these include:

• No yield benefits would be expected from water conservation measures in this year of abundant rainfall. While the modified tied ridging did not show yield benefits, farmers found it easy and practical to use. Researchers observed that system appeared to slow water movement in the field and help in reducing erosion. The system looked promising for use in drier years.
• On an “exchange visit” to see on-farm research being conducted in other semi-arid areas of the country, participating farmers became very interested in a water conservation system known as “dead-level contours and infiltration pits”. A total of about 5 farmers spontaneously started testing these systems in their own fields. This system will be included as an option for testing in the coming season.
• Grain yield response to FYM was limited in this first year of application. However, improved management of FYM (in this case, heaping and covering the manure in July, prior to application at planting) significantly improved the grain yield response. This appeared to be related to an increase in the amount of available nitrate in the FYM, as a result of the treatment.
• There was a significant difference in grain yield response to different FYM types. Goat manure gave significantly higher yields than cattle manure, at the 7% level of probability, across manure management systems. In these trials, goat manure also had higher initial levels of N.
• On average, there was a significant response to the application of limited amounts of mineral nitrogen (9 and 18 kg ha-1 N applied as ammonium nitrate). That was not unexpected in this year of good rainfall.
• In end of year assessments, farmers concluded that goat manure was more “powerful” than cattle manure. In one location, they also concluded that farmers without cash at the start of the season should apply FYM. If they had cash, they would get more immediate benefits from applying small amounts of N. However, if resources permitted, the best option was to apply both FYM and N.
• Farmers consistently indicated that seed priming did increase the rate of emergence in both cereal and legume crops (cowpeas and Bambara–it was now tried on groundnuts). While it did not show a yield benefit in this wet year, farmers felt that seed priming was a low-cost and practical option that would be useful in drier years.

The FPR program initiated in this past season will be continued in 2000/01. The purpose will be to obtain a more through evaluation of the options, and compare responses in what is likely to be a drier year.

In addition, a “Farmer Field School” program will be implemented together with extension personnel and other partner institutions. This will be done in the two current research locations as well as a third target area (Zvishavane). The objective of the Farmer Field Schools will be to provide farmers with an understanding of the basic principles of integrated soil water and nutrient management. Relevant technology options will also be presented. Participating farmers will be encouraged to experiment with the management of their available resources, based on an understanding of underlying principles. A greater understanding of the principles of integrated soil water and nutrient management is expected to enhance farmers' ability to make rational management decisions in response to changes in their biophysical and socio-economic environment, and to make them less dependent on receiving specific technical recommendations from external sources. In the same target areas, collaborative efforts with NGOs and the private sector will be undertaken, to simultaneously improve farmers' access to input and output markets. The combined program of Farmer Field Schools and improved input and output markets is the initial phase of the pilot program to facilitate adoption of improved management practices.

In Tanzania, background research and discussions with farmers and extension personnel led to the initiation of a preliminary on-farm FPR program in the 1990/00 season. In the first year, this relatively small program focused on the testing of improved, adapted pigeonpea varieties for the semi-arid areas, and evaluation of sorghum and pigeonpea production systems (both intercropping and sole cropping). The work was led by national research program scientists in the districts of Dodoma Rural and same.

The initial focus on pigeonpea and sorghum production systems was due to the fact that pigeonpea has good potential for improving and maintaining soil fertility, and also has very good market potential in Tanzania. Pigeonpea varieties adapted to the semi-arid areas have recently been identified, but are not yet available to farmers. The FPR program in Tanzania this past season included research on:

• Evaluation of pigeonpea varieties for the semi-arid areas;
• Evaluation of sorghum/pigeonpea intercropping systems;
• Community level processing and utilization systems for sorghum and pigeonpea; and
• Limited research on the use of small amounts of FYM and Urea.

The FPR program in Tanzania in 1999/00 included both RM and FM trial types. The season was very delayed, due to the late on-set of the rains. It was also a very dry year, with rainfall averaging between 20 and 25% of normal in the two target districts. Yields were very low, and a number of trials were lost to the drought. Though harvest and data analysis were very late, some preliminary results are currently available, and some useful observations could be made during the season. Highlights include the following:

• The pigeonpea varieties 0020 and 0040 proved to be very drought tolerant, with a good number of trials surviving. Grain yields of up to 500 kg ha-1 were obtained, in spite of the drought.
• A sorghum/pigeonpea intercropping system seems to be feasible in these areas, with the introduction of the new medium-duration pigeonpea varieties and improved, medium-to-early maturing sorghum (in this case, variety Pato). When planted at the same time in an intercropping system, flowering of pigeonpea varieties 00200 and 0040 started during the late grain filling stage of the sorghum.
• In Same district, sorghum survived much more frequently than maize this season, to the extent that sorghum grain was being stolen from the trial fields, and the fields had to be harvested early. This reinforced the value of sorghum as a food-security crop in this drought-prone area.
• Lastly, the application of both farmyard manure (FYM) and Urea appeared to have a positive effect on crop growth and production, even in this dry year. The effect of FYM was particularly noticeable. Yield results are still being analyzed.

In the coming season, this work will be continued, and expanded to include options for in-field soil water conservation. Planning of approaches for facilitating the broad adoption of sorghum/pigeonpea production systems and other improved soil fertility and soil water management systems has also been initiated.

 

For further details you may contact:

Dr GM Heinrich
Technology Transfer,
Bulawayo, Zimbabwe.