International Cooperation
Foreword
Highlights of the Year
ICARDA's Research Portfolio
Research Support Services
Appendices

ICARDA's Research Portfolio
Theme 2. Production Systems Management
  Project 2.2. Agronomic Management of Cropping Systems for Sustainable Production
 in Dry Areas
    
 

ICARDA has continued to address the key issues of fertilizer use, soil fertility, and soil degradation. The Center's partnership with the private sector representative IMPHOS has both considerably increased the knowledge base related to on-farm P use in WANA and provided a wide range of outputs, such as publications and conferences. Research into appropriate tillage systems has also continued, identifying and testing conservation tillage methods that conserve soil fertility, limit degradation, and benefit the environment by reducing erosion and encouraging carbon sequestration.

ICARDA's partnership with the private
sector: the phosphate fertilizer industry

Soil fertility constraints and fertilizer use in the WANA region have been a major focus of ICARDA's research since its inception. In the mid-1980s, such activities were organized, in collaboration with the region's national programs, under the umbrella of the Soil Test Calibration Network. Though the project was mainly supported by the United Nations Development Program (UNDP), financial assistance to some countries (Morocco, Turkey, Tunisia, Lebanon and Syria) was provided by the World Phosphate Institute (IMPHOS), based in Casablanca, Morocco. This initial support proved to be invaluable for the national programs, especially in conducting on-farm trials.
     IMPHOS is a non-profitmaking organization that represents a group of the world's leading producers of phosphate rock (Morocco, Tunisia, Jordan, Senegal, Algeria, Togo and South Africa). Its primary mandate is to collect and disseminate scientific information regarding the rationale for, and sustainable use of P rock and fertilizers. IMPHOS has both agronomic and technical divisions. Its scientific activities are monitored by a scientific advisory committee composed of scientists eminent in the areas of agronomy, soil science, and the environment. A major part of its mandate is to financially support various fertilizer-related technical projects in developing countries, as well as conferences and publications.
     Within a collaborative phosphate fertilizer project involving ICARDA (1997-2002), IMPHOS provided financial assistance to several of ICARDA's national partners (in Morocco, Jordan, Sudan, Yemen, Pakistan and Turkey) for applied P research. Examples of such programs include the following: the assessment of P-fertilizer use in relation to indigenous and introduced forage legumes, assessments of the interactions between P use and soil mycorrhizae, surveys of the spatial distribution of P forms in soils, field evaluation of N and P fertilizers, plant analyses for P, and nutrient budgeting. Assistance was also provided to support an M.S. graduate student. The project has already produced scientific publications and presentations, including two poster presentations at the American Society of Agronomy's meetings in 2001 and 2002, and journal articles.
     Proceedings of two technical conferences funded by IMPHOS and ICARDA ('Accomplishments and Future Challenges in Dryland Soil Fertility Research in the Mediterranean Area,' held in 1995 and published in 1997, and, 'Plant Nutrient Management under Pressurized Irrigation Systems in the Mediterranean Region,' held in 1999 and published in 2000) have been published jointly. A joint ICARDA-IMPHOS fertilizer guide for extension agents is now being prepared, and will be published in English, Arabic and French.
     The ICARDA-IMPHOS project is an example of successful collaboration between an international research organization and a private sector organization which share a common objective-the promotion of agricultural output and food security in developing countries, in conjunction with the environmentally safe use of fertilizer.

Conservation tillage as an alternative to conventional deep tillage in the cropping systems of CWANA

Over the past few decades, CWANA's dryland farming systems have become more intensive. However, in many areas, arable lands are experiencing alarming rates of degradation, either due to inappropriate soil and crop management or the impact of drought and/or erosion. Tractor use has spread to much of the region in the last 40 years, and it is now common practice to plow to a depth of 20-30 cm every year, using a disc or moldboard plow-plows designed for use in more humid and


Conservation tillage practice in Central Asia, Kazakstan.

temperate areas. Harrows or tyned implements are also used to prepare the seedbed. Regional scientists and farmers give various reasons for such deep plowing, including: the need to break up the cultivated layer, increased water and soil conservation (by preventing runoff), and weed control (through the deep burial of weed seeds).
     Unfortunately, deep tillage is not sustainable in the CWANA region. ICARDA's research has shown that it causes the breakdown and loss of soil organic matter (SOM), and so increases loss of soil C in the form of CO2-a greenhouse gas. These losses contribute to the reduction in yields that farmers are experiencing, to a reduction in soil fertility, and to soil erosion, water pollution and the greenhouse effect.

     Therefore, ICARDA has been investigating the potential for alternative 'conservation tillage' practices (i.e. 'minimum tillage' and 'no-till' systems) to increase the sustainability of arable farming in CWANA. No-till systems involve drilling seeds directly into the ground; minimum tillage involves shallow cultivation, using tyned implements which disrupt the soil to a depth of only 10 cm (once or twice before planting), or direct planting using a tyned implement combined with a drill box. Both practices minimize soil disturbance and ensure the presence of a residue cover-an important consideration in


No-till direct drill equipment for sustainable management of soil.
WANA. Conservation tillage, particularly no-till direct drilling, considerably reduces C losses (relative to conventional tillage) by reducing C mineralization rates, because the soil is less disturbed and experiences little or no exposure to radiation. By contrast, in conventional deep tillage, moldboard plows turn over the deeper soil layers, bring them to the surface, and so expose a larger surface area to radiation. Indeed, five times more C is lost to the atmosphere under conventional tillage than under no-till practices. With careful management of the soil, as reported in the literature, the potential sequestration of C per year may reach 0.1-0.2 Mg/ha for irrigated cropland and 0.05-0.10 Mg/ha for both rainfed cropland and rangeland. This has the potential to mitigate the greenhouse effect. Thus, ICARDA, in collaboration with NARS, has conducted trials in six countries, to compare conservation tillage with conventional tillage systems, within the crop-rotation systems commonly used by farmers.
     Results of trials in southern Kazakstan showed that, at a depth of 0-30 cm, the SOM content of moderately washed-out soils fell from 1.37% to 1.30% in 10 years under conventional deep plowing. However, at the same depth in soil undergoing conservation tillage, SOM content remained the same, while conservation tillage, combined with NP fertilization and straw residue or manure application, increased SOM content to 1.5% during the same period. In Jordan, Morocco, Syria and Turkey, similar results have been obtained from trials in continuous cropping systems. In Syria in particular, the no-till system increased SOM content by about 0.5% in the top 10 cm of the soil.
     This has important implications, as high SOM levels lead to improved soil structure, increased water infiltration, and also increased soil water-holding capacity and water-use efficiency in crop production-valuable in the drought-prone areas of CWANA. Soils with higher SOM contents are also more fertile, having greater nutrient cycling and storage capacities, as well as greater biological activity and diversity. Thus, conservation tillage can both reduce the need for fertilizer inputs and increase farmers' yields sustainably; it can also reduce soil erosion.
     Conservation tillage is also more energy-efficient than conventional deep plowing systems, offering savings of up to 12-18 liters of gasoline/ha. This also reduces farmers' input costs and improves their productivity, and can result in lower consumer food costs if appropriate policies are implemented.
     From a practical point of view, the tools needed for the minimum tillage system are readily available to farmers in CWANA. However, for the no-till system, suitable drills would have to be manufactured locally. Further collaboration with NARS is planned with regard to no-till drill design and agronomic practices that can be used in conjunction with conservation tillage.
     To realize the potential of conservation tillage, further socioeconomic studies are planned to document how land users are adapting their production systems to changing conditions where access to, and availability of, inputs are restricted. These studies will include analysis of short- and long-term profitability, as well as of constraints to adoption and the effects of various sociological factors. ICARDA also plans to analyze current and future policy scenarios, in order to provide policy makers with the information necessary for policy development and implementation.
     In 2002, CIMMYT and ICARDA conducted a symposium on 'Conservation Agriculture' at the Annual Meeting of the Agronomy Society of America. ICARDA scientists presented their findings on conservation tillage and direct sowing, illustrating the potential of these systems to improve crop production while safeguarding the local and global environment. To further its aim of promoting conservation tillage in the CWANA region, in 2002 ICARDA also contributed to a proposal for funding , initiated by CIRAD-France, for worldwide comprehensive conservation agriculture.