Previous Page Table of Contents Next Page

Abstracts of papers submitted during the conference, by topic

Topic 1 - Causes and consequences of soil moisture scarcity

How I would advise a farmer to use conservation-agriculture (CA) cropping; the principles of CA discussed

Many different "tillage systems" might be included under the general terminology of conservation agriculture (CA), such as "stubble-mulch tillage", "ridge tillage", and "minimum tillage". However, these systems all utilize annual or multiple broadcast tillage, i.e. complete tillage over the entire field surface area. Moreover, the word "tillage" in the terms indicates that considerable soil disturbance is part of those systems. To accomplish the goals of CA, let us dismiss broadcast tillage systems from the discussion of CA.

Country: The United States of America
Author: J.E. Morrison

Causes and consequences of soil moisture scarcity - addressing the principles to control the outcomes

Soil moisture scarcity is a major limiting factor to primary productivity and biomass production, and to many ecological processes and outcomes that determine the nature of human livelihood systems and habitat. Its crucial role in the cycle of nutrients, energy and trophic chains is highlighted by the need to understand clearly the universal principles that cause water scarcity in a given geographic location, against the background of a larger-scale water balance at the ecosystem or watershed scale, and the technical, economic, social and even political circumstances involved in soil moisture scarcity.

This paper discusses a theoretical framework outlining the fundamental principles that cause soil moisture scarcity and its many agricultural and environmental consequences. It then attempts to provide empirical and experimental evidence and data that illustrate the workings of the principles in practical experiences.

Author: R. Ponce-Hernandez

No till in rainfed agriculture in Western Africa: perspectives and challenges

No-till agriculture is promising in Western Africa. Rainfed agriculture is the rule, and water is scarce. The first rains fall on a bare soil, prone to runoff. No-till techniques have been shown to limit runoff in a striking way. Nevertheless, their application to the cropping systems is not an easy task. No-till agriculture is based mainly on protecting the soil surface with crop residues throughout the year, and on external mineral inputs. In Western Africa, crop biomass is scarce and used almost completely for livestock feeding in the dry season. External mineral input is also scarce, and crop production relies heavily on soil organic matter mineralization. Thus, even if no-till techniques seem promising in Western Africa, they also face great challenges, and scientific research needs to be undertaken in close collaboration with farmers.

Country: Mali
Author: B. Rapidel

Factors affecting soil moisture availability on sudano-sahelian coversands

Soil moisture availability is a critical factor for agriculture in the Sahel. Most soils in this region are very sandy, but they show large differences in production potentials, which are related to surface-sealing tendencies. The differences in surface crusting derive from the formation history of these coversands and they have a significant impact on water infiltration and seedling emergence. Application of crop residues enhances water infiltration. However, the amount of crop residues produced is low and the residues also have other economic uses. Empirical evidence from the Niger suggests that a high proportion of sodium and magnesium at the exchange complex increase crusting. Therefore, in the absence of sufficient crop residues, the application of calcium and potassium can be an alternative technology for improving moisture availability to crops. It is suggested that this approach be verified experimentally within a framework that would allow upscaling of local research findings to much larger areas.

Country: Niger
Author: R.L. Voortman

Understanding the process of soil erosion and water infiltration

Soil erosion is caused by non-infiltrated water that runs off a field. The process of soil erosion and water infiltration into the soil is often not well understood by farmers, or by extension workers and scientists. Pictures showing the impact of a raindrop on a bare soil surface and information explaining the mechanisms of water infiltration into the soil go back to the 1940s. Despite scientific and empirical evidence explaining these processes, many people still think that the soil has to be loosened by tillage in order to increase water infiltration and reduce runoff.

Besides increasing water infiltration and controlling erosion, soil cover has a major impact in: reducing soil temperature; reducing evaporation; increasing available water for plants; enhancing soil life and biological activity; and contributing to reduced soil compaction and soil crusting as well as having positive effects on soil chemical, physical and biological properties. All this is advantageous for the farmer and leads to higher productivity. Furthermore, permanent cover systems are essential to achieving long-term agricultural sustainability.

Author: R. Derpsch

Use of compost as an alternative to synthetic fertilizers for crop production and agricultural sustainability for the island of Guam

A major problem of agricultural soils in the tropical region of the Pacific is the low organic matter content. Composted organic material is being applied on agricultural fields as an amendment to provide nutrients and also to enhance the organic matter content and improve the physical and chemical properties of the cultivated soils. Composted organic material contains essential nutrients for plant growth, especially nitrogen and phosphorous. Land application of composted material as a fertilizer source not only provides essential nutrients to plants, it also improves soil quality and disposes of wastes effectively.

In our soil programme at the University of Guam, we are evaluating the use of organic material as an alternative to synthetic fertilizers. Our goal is to develop management strategies and use available resources for improving crop production while conserving resources and preserving environmental quality. Our case-study project is designed to improve soil fertility status by using composted organic wastes and assessing how nitrogen and other essential nutrients contribute to long-term soil fertility and crop productivity without the application of synthetic fertilizers. In our pilot project, compost is produced from wood chips from grinded typhoon debris mixed with animal manure, fish feed, shredded paper and other organic wastes. Mature compost is then applied on the field at the rate of: 0, 5, 10 and 20 tonnes/ha as a soil amendment on the eroded cobbly soils of southern Guam. Corn is planted and monitored for growth performance and yield. The effect of land application of composted material on the soil organic matter content and other properties such as the soil quality indices are being evaluated in this pilot study.

Country: Guam - The United States of America
Authors: M.H. Golabi, M.J. Denney and C. Iyekar

The evolution of soil structural repair under zero till, controlled traffic, and permanent-bed farming

Soil structural degradation is widespread in cropping lands and efforts to restore deteriorated soil structure very often fail, largely as a result of tillage and traffic effects. Significant reductions in biological activity in the soil environment occur where random traffic is practised, limiting the regenerative capacity of Vertosols. This study assessed the changes in soil structure after random field-wheeling was replaced with zero-till permanent-bed controlled traffic farming (CTF) through four cropping seasons. The rate and depth of soil amelioration by natural processes was assessed by changes in soil water retention characteristics, macroporosity and bulk density.

At time zero, there was no evidence of the characteristic slickensides found in well-structured Vertosols. Soil moisture characteristics indicated that the available water capacity (AWC) was 10.2 mm per 10 cm depth of soil. Amelioration of the soil matrix increased AWC to 15.4 mm per 10 cm depth of soil. Macropore density improved from very marginal conditions by 50 percent at a depth of 100 mm and by 27 percent at a depth of 400 mm. Bulk density at 1.40 g/cm3 was typical for a degraded Vertosol at time zero. However, values improved significantly to 1.25 g/cm3 at a depth of 100 mm, with deeper zones improving to 1.30 g/cm3.

Significant gains in production can be made by CTF, by expansion of the unimpeded rootzone, through increased water percolation, air-filled porosity, pore size redistribution and AWC. Therefore, as a result of these soil physical changes, it follows that weed control, seed-bed preparation and planting should require less power, there should also be an improved timeliness of operations, and there could also be significant implications for soil opening devices and engagement tools

Country: Australia
Authors: A.D. McHugh, J.N. Tullberg and D.M. Freebairn

Rainfall effects on rainfed crop yields and water use

One of the most limiting factors to rainfed crop yields in dryland conditions in northern China is a large rainfall variation in time and amount, which influences water availability and crop-yield stability. This paper provides an analysis of site-rainfall variation effects on rainfed crop yields and water use according to data from past and ongoing dryland farming research projects in northern China. The water use for both wheat and corn has good linear correlations with growing season rainfall. Wheatyieldsaresensitivetotheamountofannualrainfall,whereascornyieldsareheat yields are sensitive to the amount of annual rainfall, whereas corn yields are sensitive to the critical time of water supply (especially April, June and July rainfall). Therefore, appropriate conservation-tillage practices (ones that can increase seasonal rainwater infiltration and water storage, or reduce surface runoff and evaporation, and further enable a supply of more available water for critical water use by crops) could be developed based on yield-rainfall relations.

Country: China
Authors: X.B. Wang, D.X. Cai, U.D. Perdok, W.B. Hoogmoed and O. Oenema

Dryland agriculture and conservation technologies for improving soil moisture for crop production in semi-arid Kenya

Dryland agriculture is practised where there is water stress and seasonal agricultural drought owing to low water supply (low rainfall, high runoff-water losses and high evaporation). In dryland agriculture, emphasis is on conservation of soil water for crop production. Typical characteristics of dryland areas include: low total rainfall with at least one pronounced dry season; highly variable and unreliable rainfall during the normal rainy season with temporal (year to year, month to month) variations in rainfall amount and distribution; increase in persistence of agricultural drought with decreasing rainfall; potential evapotranspiration exceeding rainfall for at least seven months of the year; and very high-intensity rainstorms of short duration that often lead to high surface runoff and soil erosion. Thus, limited soil water supply and a serious erosion potential are the two most common characteristics in all dryland areas.

Conventional tillage operations using the ox-drawn mould-board plough resulted in the development of plough pans below a maximum ploughing depth of 10 cm. In addition, there was the natural subsurface hardpan that is attributed to clay eluviation in the Bt horizon. Breaking of subsurface hardpans calls for conservation-tillage techniques that improve the depth of tillage to 25-30 cm and, thus, enhance soil moisture storage in the soil. Deep or shallow tillage could be recommended on the basis of seasonal soil conditions as influenced by rainfall characteristics.

Country: Keny
Author: E.K. Biamah

Topic 2 - Creating drought-resistant soil - Technologies and impacts of improved soil moisture management at field level

Inappropriate narrow technological-based approach on soil moisture management for the poor farmers in the Sahel

Contrary to what is often asserted, valid solutions to improve soil moisture management are rarely available. Proposed solutions are generally not appropriate and have caused numerous projects to fail because they are essentially based on a technological approach. The establishment of sustainable solutions to improve soil moisture management requires a global knowledge of the farming systems as well as farmer participation and respect for traditional knowledge.

Region: Sahe
Author: M. Ferry

Vegetable production using raised permanent beds

Under conventional practices, vegetables are grown on the flat or on ridges on freshly cultivated soil. In the tropics and subtropics, where it is possible to obtain two or more crops per year, constant soil cultivation leads to rapid depletion of organic matter and, under mechanized conditions, the creation of hardpans or plough plans, resulting in soil infertility and predisposing the soil to erosion. Moreover, pedestrian traffic causes further soil compaction and the spread of disease by footwear. Under rainfed or overhead sprinkler and drip irrigation, there is a strong case for growing vegetables on raised permanent beds, which can be constructed manually or mechanically using a ridger. The permanent-bed system for vegetable production represents a minimum input system that fosters soil fertility over time. The converse is true for conventional tillage practices, viz. reducing levels of soil organic matter and increasing applications of inorganic fertilizers and pesticides with declining soil fertility.

Author: F. Scanlan

Think like a root. Land husbandry and the conservation of water and soil: a précis

Land is definable within a five-dimensional matrix. Husbandry of land is concerned with improving and sustaining its ongoing capacities to yield plant materials and water, as well as other satisfactions. The self-recuperating capacity of soil - particularly with respect to re-formation of porous soil architecture - depends on favouring ongoing transformative activities of soil micro- and meso-organisms. Effective and sustained conservation of water and soil is best achievable primarily by biological means. Conservation-effective actions within preferred land-use systems are more significant than only conservation-specific works on the soil surface. Relevant knowledge and understanding of dynamics at the microscale are needed in order to inform planning and actions at the macroscale. Therefore, it is necessary to think like a root, think like a soil microbe, and think like a river in order to work out what conditions within a landscape need to be achieved simultaneously in order to sustain its capacities to continue yielding both plants and water.

Author: T.F. Shaxson

No till can improve soil functioning and water economy

The no-till system is very effective for increasing soil water infiltration, and for reducing evaporation from soil and reducing water runoff. The water availability for crops is increased, offering the opportunity to improve general soil functioning and crop performance.

The principles are equally useful for both rainfed and irrigated cropping conditions. Under rainfed conditions, no till contributes greatly to minimizing the yield impacts of water-stress periods, so enabling higher and less variable crop yields. Under irrigated conditions, no till can contribute significantly to reducing the amount of water needed to develop a given crop. These beneficial characteristics of no till are associated with other important positive impacts. Among them, the reduction in water runoff and the consequent reduction in (or avoidance of) soil erosion is a relevant one. Moreover, the crop residues covering the topsoil create a favourable environment for a significant increase in biological activity, which further improves the soil and general agro-ecosystem functioning.

Country: Argentina
Author: R. Peiretti

Conservation farming - a strategy for improved agricultural and water productivity among smallholder farmers in drought-prone environments

Water is a primary limiting factor for crop growth in semi-arid and dry subhumid savannah agro-ecosystems. However, this is not necessarily because of low seasonal rainfall but rather a poor distribution of rainfall and large losses of water in the on-farm crop-water balance. Conservation farming, which aims at maximizing rainfall infiltration, waterholding capacity and crop-water uptake capacity, is an effective in situ water-harvesting strategy for smallholder farmers in drought- and dry-spell-prone savannahs. This paper presents on-farm farmer-driven trials on tractor-based, animal-drawn and manually based conservation farming systems. As shown from trials in semi-arid regions of Madagascar, Sudan and United Republic of Tanzania, yield differences between conservation farming and conventional ploughing were significant and largest in the driest years - an indication of the water-harvesting effect. The largest yield increase was realized when water harvesting through conservation farming was combined with soil fertility management, resulting in an average yield increase exceeding 200 percent compared with current local practices. Rainwater productivity increased substantially from 3 800 m3/tonne required for the conventionally ploughed system compared with an average of 1 500 m3/tonne for maize under conservation farming. The paper further discusses the challenges of achieving wider adoption of conservation farming practices, and the wider advantages in terms of labour saving, which is particularly important in the region because of the HIV-AIDs pandemic.

Country: Madagascar, Sudan, and the United Republic of Tanzania
Authors: J. Rockström and K. Steiner

Improving rainwater productivity in the north of the united republic of Tanzania

Crop failures caused by prolonged dry spells have become more frequent in southeast Africa in the last decade. However, although farmers complain of a lack of rainfall, a substantial part of rainwater is lost as a result of soil degradation caused by inappropriate land management. Soil compaction is a widespread phenomenon that impedes water infiltration and deep rooting of crops. Break compaction layers by subsoiling and preventing recompaction by conservation tillage and deep-rooting cover crops can increase rainwater productivity significantly and prevent crop failure in dry years.

Country: The United Republic of Tanzania
Authors: K. Steiner and W. Marik

Think like a root: the land husbandry context for the conservation of water and soil

Land is definable within a five-dimensional matrix. Husbandry of land is concerned with improving and sustaining its ongoing capacities to yield plant materials and water, as well as other satisfactions. The self-recuperating capacity of soil - particularly with respect to re-formation of porous soil architecture - depends on favouring ongoing transformative activities of soil micro- and meso-organisms. Effective and sustained conservation of water and soil is best achievable primarily by biological means. Conservation-effective actions within preferred land-use systems are more significant than only conservation-specific works on the soil surface. Relevant knowledge and understanding of dynamics at the microscale are needed in order to inform planning and actions at the macroscale. Therefore, it is necessary to think like a root, think like a soil microbe, and think like a river in order to work out what conditions within a landscape need to be achieved simultaneously in order to sustain its capacities to continue yielding both plants and water.

Author: T.F. Shaxson

An ecological background to concepts of land husbandry

Land is the basic resource of a nation. To provide for all of his needs, man must use land for many purposes. He needs land to produce food, fibre, timber and water, for urban and industrial purposes, for transport by roads, railways and airports, for the extraction of minerals and building materials, for distributing power by transmission lines and pipelines and for the safe disposal of wastes. But he also needs land for nonproductive purposes: for recreation and enjoyment; and land in its natural state to serve as reference areas and as habitat for the vast array of species of plants and animals, a great repository of genetic material that could be of value in the future. The most important requirement at present is for everybody to be made to understand that soil conservation is more than erosion control and that it is not just an agricultural problem. Soil conservation is really a matter of applying the appropriate uses to different kinds of land.

Author: R.G. Downes

Principles of good land husbandry: achieving conservation of land's productive potentials

The concept of 'husbandry' is widely understood when applied to crops and animals in the sense of 'looking after them'. As a concept signifying active understanding, management and improvement, it is equally applicable to land. In the case of land, a primary concern is to maintain its productive capabilities and to avoid their degradation. Land degradation may result from decline in biological, chemical or physical attributes of the soil, such as decline in organic activity, water logging, acidification, loss of porosity, and/or the loss of soil particles, nutrients and runoff. Across a varied area of land, achieving conservation requires that husbandry should be so adjusted to each homogeneous sub-area that any rate of degradation is effectively minimized, and that no one part 'wears out' or becomes unproductive more quickly than any other. In a given situation, suggestions for improvements in land husbandry should be developed together with rural people, using their knowledge, awareness of problems, analysis, insights, capacities, skills, goals, aspirations, enthusiasms and priorities.

Country: The United Kingdom
Authors: T.F. Shaxson, M.G. Douglas and R.G. Downes

Wind erosion and its impact on soil carbon and moisture scarcity

This review discusses the duststorm-related soil erosion and its impact on soil carbon losses and moisture scarcity in northern China. Heavily affected areas show a loss of nutrients, organic carbon and field water capacity of soils. Compared with non-degraded soil, the carbon content in degraded soils has declined by 66 percent, and field water capacity by about 50 percent. Field studies suggest that soil losses by wind erosion can be reduced by up to 79 percent when farmers change from conventional tillage methods to no till. Thus, shifting to no-till or reduced-tillage systems is an effective practice for protecting soil and soil nutrients. Our study indicates that soil conservation measures along with improved soil fertility management measures should be promoted in dryland farming areas of northern China.

Country: China
Authors: X.B. Wang, D.X. Cai, O. Oenema, U.D. Perdok, and W.B. Hoogmoed

Topic 3 - Environmental consequences of drought-resistant soil and improved soil moisture management

Managing the water balance - how farmers determine green and blue water flows in the save basin in Zimbabwe

Water security is a principal concern for the twenty-first century. The productivity of rainfed farming in sub-Saharan Africa (SSA) is far below its potential, yet rainfed agriculture will remain the dominant system for decades to come.

In semi-arid and subhumid regions in SSA, rainfed agriculture uses only 15-30 percent of the rainwater for crop production. High losses are caused by runoff, low infiltration during high-intensity rains, poor crop-rooting conditions, past and present soil erosion, and evaporation losses from soil and canopy, in particular during pre-planting and early crop stages. In addition, runoff causes damaging flash floods, erosion and water turbidity, and without storage devices downstream, a substantial volume of water runs out of the catchments.

Country: Zimbabwe
Authors: S. Kauffman and G. van Lynden

Situation of drought in Bosnia and Herzegovina

This paper analyses the general situation in Bosnia and Herzegovina and that regarding: drought (through soil water budgeting); the land (referential lowland or flat zones in the river valleys, karstic fields, and hilly, mountain and upland zones); irrigation; and antidrought measures for drought mitigation.

Country: Bosnia and Herzegovina
Authors: H. Custovic, M. Vlahinic and E. Alagic

The great role of seabuckthorn in eco-environmental construction in northern China

Seabuckthorn is called a pioneer in soil and water conservation and poor-environment improvement because of its high capability of resistance to drought and poor soil condition and strong shooting and nitrogen fixing. It must be a high-potential plant for development in rural and mountain areas with its great economic value.

Country: China
Author: Chinese National Administration Center for Seabuckthorn Development

No-fallow farming

Summer fallow is believed to be an obligatory part of dryland farming systems in many parts of the world. The reasons for summer fallow include moisture conservation, weed control, and pest and disease management. Economic considerations are also important. However, in practice, summer fallow is contributing greatly to soil degradation through soil erosion both by wind and water. Studies conducted from 1983 to 2003 in northern Kazakhstan indicated that there are opportunities to farm successfully in dryland agriculture without summer fallow while increasing grain production and sustainability of farming. In western Siberia adjacent to northern Kazakhstan, one farmer has been farming 28 000 ha successfully without summer fallow for more than ten years. This article reports on research and practice in no-fallow dryland agriculture.

Country: Kazakhstan
Author: M. Suleimenov

Topic 4 - Adequate tools and technologies to support efficient soil moisture management

Adequate tools and technologies to support soil moisture management

Soil moisture measurement is critical for managing water resources in an efficient manner. This applies to both irrigated and rainfed cropping systems. Water is increasingly becoming the most limiting resource needed to meet the food and fibre needs of a growing and more affluent population. The feel and appearance method and the soil probe method for measuring plant-available soil moisture are quick, low cost, and suitable for many situations. Although they are not as accurate as some other methods, the information they provide can be extremely useful. The first decisions that must be made in choosing a method are to determine what the information is going to be used for and how accurate the information must be before its usefulness is muted. Neither the feel and appearance nor the soil probe method would be an acceptable method for conducting a water-balance research study, but both of them can be very helpful for producers and consultants making decisions about when and what crops to grow and for assessing the probabilities of producing economic crop yields.

Author: B.A. Stewart

Models of conservation agriculture - conclusions and implications

Models can improve our understanding of the behaviour of complex systems such as all the aspects involved in conservation agriculture. The conference background paper on modelling of conservation agriculture may have some shortcomings, but the results are appealing and problematic. They confirm experimental evidence from West Africa that sufficient crop residues can be produced under humid conditions, but their application has no yield effect, while under drier conditions, the effects are considerable, but it is difficult to produce sufficient quantities. Massive adoption of residue application under humid conditions apparently derives from savings on labour costs. Under different environmental conditions, different kinds of farmers may thus decide to go or not to go for residue application for entirely different and perfectly rational reasons. This calls for the development of a coherent analytical framework on the conditions for and potential benefits of conservation agriculture.

Author: R.L. Voortman

Environmental conditions, the need to understand operating mechanisms and the possible role of mycorrhizae

This paper emphasizes the need to understand the operating mechanisms of how natural conditions and land and crop management affect water and nutrient availability, and, ultimately, crop yield. Such effects have to be related to the environmental conditions in which they occur. It is observed that some soils have a natural tendency towards accumulation of organic matter while others do not. This appears to be related to soil chemistry as determined by parent material. The paper suggests investigating which soil chemical factors determine the natural tendency for organic matter accumulation and whether such effects can be provoked by fertilizer application. It is further observed that the conference does not pay attention to the role of mycorrhizae, which in most, if not all, ecosystems play a crucial role in the supply of water and nutrients to crops, and also increase organic matter and improve soil structure.

Author: R.L. Voortman

The simple and low-cost method for soil moisture monitoring

The first step in choosing the method for soil moisture monitoring is a question: why do we need this information? Usually, we need this information in irrigation practice in searching for the answer as to when and how much water to apply. It is possible to find the answer by soil moisture measurement. There are a lot of methods for soil moisture measurement, e.g.: gravimetric, tensiometric, gypsum-porous blocks, electrical resistance method, and neutron probes. All of these methods need trained people to apply them and they are not acceptable to small farmers. Some of them are very expensive and need laboratory measurements on the terrain. In addition, the results obtained by these methods are not exact; they are just approximations.

Country: Bosnia and Herzegovina
Authors: M. Vlahinic and H. Custovic

Using models for optimizing soil moisture management strategies

Farmers and extension services are interested in or are actively experimenting with new crop options, including conservation agriculture methods, direct seeding, minimum-tillage methods, and crop-residue management. In order to develop cropping systems that are well suited to the environmental conditions, the agronomic performance of the envisaged systems needs to be understood. Given the large number of potential options and the desire to develop viable cropping systems as rapidly as possible, we suggest investigating options using crop modelling as virtual field research experimentation.

Authors: F. Maraux, E. Scopel and A. Findeling

Topic 5 - Conditions for adoption of drought-proofing practices by farmers

Soil moisture conservation under conservation agriculture

Soil moisture management and enhanced soil organic matter are implicit in the new farming systems called conservation agriculture (CA). CA is not "business as usual", but rather it is based on achieving a balance of agricultural, economic and environmental benefits. Experience in many countries has shown that CA, where practised correctly, is effective in mitigating the impacts of droughts even in difficult years by conserving soil moisture and providing some minimal levels of production. CA systems are more sustainable than conventional agriculture because of the focus on producing healthy soils.

Authors: J. Dumanski and R. Peiretti

Indigenous technology - a basis for soil and water conservation research

Runoff farming and water harvesting are practices that aim at concentrating rainfall water and they favour local crop growth through more effective use of rainwater. However, they are restricted to specific conditions for their effectiveness in improving water-use efficiency.

Most of the runoff water is harvested either in embankment or dug-out reservoirs in the Shiwaliks region of the Himalayan ecosystem. However, while importance is given to diversion of rain-runoff water in these reservoirs, nothing is done about the unabated soil erosion in the catchment areas. The result is a buildup of sediment concentration in the runoff water, which results in siltation of these reservoirs, thereby making them useless within a couple of years.

Country: India
Author: S.S. Kukal

Problems associated with the adoption of rainwater-harvesting technology for increased agricultural production in southwest Nigeria

Agricultural production in the West Africa subregion has decreased drastically in the past decade, whereas its population has increased significantly. The importance of agriculture to the national economy has recently led to a growing awareness about problems at various levels of agricultural production and practices. One of the issues is management of the resource base (the soil and water) and the development of appropriate technology to meet the challenges of intensive agriculture. Most agricultural activities in southwest Nigeria depend solely on direct rainfall. Consequently, when rain fails or falters, it usually results in a serious shortage of plant-available water with severe negative effects on crop and livestock production.

This paper discusses and highlights basic problems linked to the adoption of "technologies" at various levels between researcher and farmer via the extension delivery agents. It also examines some of the problems related to the adoption of rainwater-harvesting technologies by farm households in southwest Nigeria in which various physical, environmental, cultural, social and institutional factors play an important role. The findings show that rainwater harvesting for crop production has not received adequate support from research and extension services. Therefore, there is the need to bridge the gap between appropriate rainwater-harvesting technologies and the existing soil water conservation knowledge, attitude and practices of the farmers.

Country: Nigeria
Authors: D.A. Okunade and K.O. Adekalu

Nutrients, water and conditions for technology adoption in West Africa

It has been argued that, in the drier parts of West Africa, soil fertility rather than moisture availability is the main constraint on agricultural production. This contribution shows that the soils are very poor indeed, but also presents data on interannual as well as within-year very local yield variations caused by differences in moisture supply (implying a need for precision agriculture). Our work shows that nutrients can substitute for water, and vice versa. Yield-function analysis suggests that technologies can be developed that improve both nutrient and moisture supply. The combination of small doses of fertilizer at lower drought-risk levels is likely to be attractive to cash-constrained and risk-averse farmers (a win-win situation). Last, we bring forward some general issues related to technology adoption. The implications are that a profound change in the research and extension system is required.

Author: R.L. Voortman

Food security and economic development in sub-saharan Africa - investment in soils or in irrigation?

Rainfed or irrigated agriculture? In sub-Saharan Africa (SSA), 4.5-6.0 million ha are irrigated while the harvested area under rainfed cropping is 150 million ha. Potentially, 40 million ha can be irrigated, and hundreds of millions of hectares can be made available for rainfed agriculture. Through soil improvement, cereal yields in SSA could increase from the present 1 000 kg/ha to an average of 5 000 kg/ha; through irrigation, while rice production levels of 2 000 kg/ha/year could increase to an average of 10 000 kg/ha/year.

It is an intriguing question why government and donor investments concentrate almost exclusively on irrigated agriculture.

Region: sub-Saharan Africa
Authors: H. Breman, M. Wopereis, A. Maatman, D. Hellums, N. Chien and W. Bowen

African soils step-motherly served by nature, governments and donors (strategies to improve fertilizer use efficiency in west Africa)

The integrated soil fertility management (ISFM) is the integrated use of inorganic fertilizers and soil amendments (levels and quality of organic matter, sources of phosphorus and/or lime). These amendments improve the soil organic matter status, increase the accessibility of phosphorus, buffer acidic soils, and improve the capacity of soil to retain plant nutrients and moisture against leaching. Among the amendments, sources of organic matter are the most critical, followed by phosphorus. On acid soils, the use of phosphate rock may serve a double goal - decreasing acidity and adding phosphorus over an extended period of several years -, if not, lime is also required. The ISFM approach is more than technology. It refers to a participatory process that includes on-farm development, validation and extension of intensified production systems that sustain productivity over time.

Authors: Henk Breman, Arno Maatman and Marco Wopereis

International certification standards for no-till / zero-till - A framework for discussion

Certification systems are already going on in a number of areas in the resource provider industry. We have forestry certification programs like SFI 2002-2004 (Sustainable Forestry Initiative System and ISO 14001 (Environmental Management System standard). Livestock and cropping systems are entering the fray from many angles, each hoping to attach a label or certification to their practices. "Organics" and "natural food" suppliers have been forced to define just what they mean by these terms and have had to develop standards and certification procedures for meeting the standards. Many international leaders in the conservation tillage field keep surfacing the idea of moving to a certification process for no-Till / zero-till farmers. What we are talking about is basically a quality assurance program that might seek the potential goal of insuring cropping system management processes is environmentally sustainable and economically viable.

Country: United States of America
Author: Dick Wittman

Previous Page Top of Page Next Page