Intensification of conservation agriculture systems for increased livestock feed and maize production in Zimbabwe

Livestock and crops are key components of mixed farming systems and are a source of household food and income. However, mixed farming systems face livestock feed shortages and low soil productivity challenges. Conservation agriculture (CA) systems based on minimum soil disturbance, crop residue retention and crop rotations offer an opportunity to grow both fodder and food crops on the available land to improve productivity and crop output per-unit area. A four-year experiment involving maize monocropping as control treatment and four relay or intercropping treatments with different legume and fodder crops was set up on contrasting soils in Zimbabwe. Lablab was superior in biomass production compared with radish on both soil types. On the clay soil, continuous maize, sole lablab, sole radish, maize/lablab relay and radish/common beans relay treatments produced similar biomass when soil moisture was adequate. When soil moisture was limiting, lablab produced more biomass than continuous maize, radish, maize/lablab relay and radish/beans relay treatments on clay soil. On sandy soils, lablab produced more biomass than continuous maize, radish, maize/lablab relay and radish/beans relay treatments. Leguminous and non-leguminous fodder crops can be grown successfully in CA systems that are being promoted in the mixed crop/livestock farming systems of southern Africa.     

Feasibility of conservation agriculture in the Amu Darya River Lowlands,Central Asia

Human-driven land degradation threatens economic and environmental sustainability of irrigated agricultural production such as in Central Asia. Many current challenges can be eased by implementing Conservation Agriculture (CA), with however unknown financial consequences under the predominating irrigated conditions. We applied the linear programming to compare costs and benefits of four CA production systems, which are cotton-based rotation systems including (i) cotton-cotton and (ii) cotton-wheat-maize rotations under conventional tillage (CT), as well as (iii) cotton-cover crop-cotton, and (iv) cotton-wheat-maize rotations with mulch cover (crop residue retaining) and both rotations under permanent-bed planting (PB) with minimum tillage. All systems were subjected to six levels of land quality and a series of crop pricing schemes. Data were extracted from empirical research on CA in Uzbekistan, complemented with data on input and output prices from surveys. The findings underpinned the financial advantages of more diversified cropping systems (cotton-wheat-maize) over the crop monoculture (cotton-cotton-based system). Crop cultivation on marginal land was unprofitable under CT. In contrast, crop production under PB could generate profits even on croplands with a lower productivity level considered. It is argued that PB with crop residue retaining and applied in cotton-wheat-maize rotation shows most promise for improving crop yields and income.     

Strategies for sustainable intensification in East African highlands: labor use and input efficiency

Strategies for poverty alleviation and sustainable natural resource management usually focus on land use options for improving yields. Increasing the returns to critical factors requires possibilities for input substitution. Inadequate timing of input applications or nonavailability of complementary factors can seriously hinder this substitution. Such constraints particularly apply in less‐favored areas where soil organic matter content is too low for enabling efficient nutrient uptake and soil structure limits water infiltration and moisture retention. This article focuses attention on the importance of labor for crop management activities and input applications that enhance input efficiency in highland area cropping systems of Northern Ethiopia. Given the inherent complementarities between labor and nutrient supply during critical phases of the plant growth process, input efficiency strongly depends on labor use. We present a semiparametric bioeconomic modeling approach to analyze the available options for improving input efficiency in agricultural production. Input response equations are used that consider the returns per unit of land and labor as a function of specific combinations of material inputs and management practices. Critical trade‐offs may arise when opportunity costs for labor are considered or when complementary factors appear as binding constraints. The model enables assessment of feasible pathways for enhancing sustainable intensification and poverty alleviation in typical settings of the East African highland region.     

The estimation of agricultural policy effects on soil erosion—An application for the bio-economic model MODAM

As agricultural policies affect land use, they have effects on the amount of soil erosion in agricultural regions through changes of the economic conditions of agricultural production. Prices of inputs and outputs, regulations and incentives can change, forcing or encouraging farmers to adopt new crop rotations. This paper shows how a bio-economic model can be used to describe and estimate the effects of policies on agricultural production and the risk of soil erosion at the example of a region in North-Eastern Germany. The model uses both an assessment tool that is based on a fuzzy-logic approach for the estimation of soil erosion risk of cropping practices, and a linear programming model, that simulates farmers’ economic behaviour under the assumption of gross margin maximisation being the main goal of farmers’ actions.The analysed policy options were both a targeted and an untargeted incentive programme for reduced tillage, and a restriction option where high erosive crops are not allowed on high erodible field types. The results show that policy changes can have an impact on soil erosion. Furthermore, soil conservation policies are shown to have different levels of efficiency in terms of reduced soil erosion related to the costs of the policy. In the case of this study, a restriction option was more efficient than the incentive options. The results of such simulations can serve as a decision support for the development of soil conservation policies and help to foresee the effects of general changes of agricultural policies.     

From Microlevel Decisions to Landscape Changes: An Assessment of Agricultural Conservation Policies

The growth in conservation programs has created a need for modeling frameworks capable of measuring microlevel behavioral responses and macrolevel landscape changes. This paper presents an empirical model that predicts farmers' production practices and the resulting levels of agricultural runoffs at more than 42,000 agricultural sites in the upper-Mississippi river basin under alternative conservation policies. Results suggest that payments for conservation tillage and crop rotations increase the use of these conservation practices. However, the acreage response is inelastic and the programs are not likely to be cost effective on their own for addressing hypoxia problem in the Gulf of Mexico.     

Soil and cropping system research in semi-arid West Africa as related to the potential for conservation agriculture

Semi-arid West Africa faces challenges to increase sorghum and pearl millet production to meet food needs for a growing human population while increasing soil carbon (C), nutrient levels, and water holding capacity that are documented benefits of conservation agriculture. This review focuses on the wealth of research on cropping systems, tillage, crop residue, nutrient, and weed management as related to conservation agriculture. It also identifies needs for multidisciplinary, integrative research to assist the transition from current production systems to conservation agriculture. Crop residue use as livestock feed, or fuel are major constraints to adoption of conservation agriculture, which could be reduced by wood production in agroforestry systems, alternate energy sources, and increased forage supply. Crop residue and grain yields are related, thus improved crop, soil, water, nutrient, and weed management to increase grain yield would also increase the supply of crop residue with potential for ‘left over’ crop residue being available for soil mulching. Incorporating indigenous shrubs and/or cover crops could also increase crop residue supply. Species diversity can be increased through crop rotation, agroforestry, cover crops, and intercrops. Higher grain and stover yields and increased profit potential for resource-poor farmers in West Africa will be required before wide-scale adoption of conservation agriculture will be possible.     

Conservation agriculture practices adopted in southern Brazil

The adoption of conservation agriculture (CA) practices are essential for soil and water conservation. In CA, farmers must adopt no-tillage (NT) with crop rotation to maintain a permanent soil cover. In Brazil, mainly in the South region, for CA to be more efficient, practices such as contour farming and agricultural terraces should also be adopted. Thus, the objective of this study is to determine the extent to which NT has been adopted with crop rotation and others soil and water conservation practices. Data from the Agricultural Census in Paraná State, southern Brazil, were used. For the data analysis, the relationship between the level of adoption of NT and the use of crop rotation, contour farming and agricultural terraces was analyzed. A factor and cluster analysis were performed to distinguish regions in terms of soil and water conservation practices. The results show good overall soil and water conservation practices, although heterogeneity has been observed in the adoption practices between regions. Adoption of NT is high in almost all the studied regions. The conservation practice most widely used with NT is contour farming, whereas the least used is agricultural terraces. Conservation practices for runoff control are being neglected by farmers.     

Soil and Moisture Management in Mali: A Case Study Analysis for West Africa

In order for farmers to accept improved soil and water management practices, new technologies must be appropriate to the specific site conditions found in the farm setting and be consistent with farmers' objectives and available resources. A whole-farm modeling analysis of this problem is described. Preliminary estimates of the benefits of increased soil moisture conservation for representative low-resource farmers in Mali are presented. If farmers could improve rainfall infiltration from currently low rates of about 40% up to 60%, and use small amounts of chemical fertilizers, disposable income could increase two to four times depending on rainfall. Income could be increased another 50% if the infiltration rate was raised to 80%. Food grain production could increase 60 to 90% with improved moisture conservation and fertilizer use.     

Adoption of climate‐smart practices and its impact on farm performance and risk exposure among smallholder farmers in Ghana

Increased climate variability during the last four decades has made the agricultural environment in many developing countries more uncertain, resulting in increasing exposure to risk when producing crops. In this study, we use recent farm‐level data from Ghana to examine the drivers of individual and joint adoption of crop choice and soil and water conservation practices, and how adoption of these practices impacts on farm performance (crop revenue) and exposure to risks (skewness of crop yield). We employ a multinomial endogenous switching regression model to account for selectivity bias due to both observable and unobservable factors. The empirical results reveal that farmers’ adoption of crop choice and soil and water conservation leads to higher crop revenues and reduced riskiness in crop production, with the largest impact on crop revenues coming from joint adoption. The findings also show that education of the household head, access to extension and weather information influence the likelihood of adopting these practices. Thus, enhancing extension services and access to climate information and irrigation can reduce gaps in adoption of soil and water conservation and crop choice, considered as climate‐smart practices that will eventually improve crop revenues and reduce farmers’ exposure to climate‐related production risks.     

Soil,water and crop management alternatives in rainfed agriculture in the Sahel: an economic analysis

Most agriculture in the Sahel Region is carried out under rainfed conditions where low and uncertain soil moisture levels limit productivity. Improved soil, water and crop management practices are required to reverse the steady decline in per capita food production and sustain output over the long term. Several technological innovations and related farm management practices are evaluated in a case study of a typical farm in Mali. Through use of a soil-water balance model and a whole-farm economic model an optimal mix of these measures is identified. Compared to a base case where no modern inputs are utilized, the combination of animal traction (oxen team), low levels of NPK fertilizer, tied-ridges, traditional long-season food grain crops and early planting was most effective: food grain output was 35% higher than with the traditional base case; soil erosion was reduced by 72%; and even with residual future soil erosion damage capitalized into current income, net farm income was larger by a factor of almost 45.     

Adoption of conservation agriculture in Europe: Lessons of the KASSA project

According to KASSA findings, conservation agriculture is less adopted in Europe compared to other adopting regions and, reduced tillage is more common than no-tillage and cover crops. Currently, it is not popularised and it is less researched. The lack of knowledge on conservation agriculture systems and their management and, the absence of dynamic and effective innovation systems make it difficult and socio-economically risky for European farmers to give up ploughing which is a paradigm rooted in their cultural backgrounds. In Norway and Germany the adoption of conservation agriculture has been encouraged and subsidised in order to mitigate soil erosion. In the other European countries the adoption process seems mainly driven by farmers and, the major driving force has been the cost reduction in machinery, fuel and labour saving. Soil and water conservation concerns did not appear as main drivers in the European farmers’ decision to shift or not to conservation agriculture.The shift of European farmers to conservation agriculture is being achieved through a step-by-step attitude, large scale farms are the most adopters. This adoption trend may grow in the future. Indeed, the need to improve farms’ competitiveness, the market globalization and the steady increase of fuel cost will likely contribute to arouse European farmers’ interest in conservation agriculture as it slashes significantly the production costs.Conservation agriculture is not equally suitable for all the European agroecosystems. The need of soil and water conservation in Europe requires anticipating the ongoing process in order to improve its ecological and socio-economic sustainability. Priority would be to define which regions in Europe are the most suitable for conservation agriculture taking into account climate and soil constraints, length of growing period, water availability and quality, erosion hazards and farming conditions. Policy favouring the use of soil cover and profitable crop rotations as management strategies for weed, pest and diseases control will certainly allow developing and disseminating efficient and acceptable conservation agriculture systems.     

Red clover (Trifolium pratense) in conservation agriculture: a compelling case for increased adoption

The rapidly growing population will soon require a near doubling of food production. This increase must be achieved in a manner that maintains environmental integrity, preserves public health and resolves food access and distribution equalities. The use of forage legumes in arable rotations can make significant and multidimensional contributions to this sustainable intensification and this paper reviews the potential contribution of red clover (Trifolium pratense L.), with particular reference to sustainable cereal production in conservation agriculture systems. The use of red clover as a tool in soil fertility-building and the multiple benefits to the cropping system in which it is used is described. The benefits discussed include atmospheric nitrogen fixation, soil conservation, structural soil improvements and a suite of agroecosystem services including increased soil microbial activity, the phytoremediation of polluted soils and the provision of food for pollinators. Reported allelopathic weed suppression by red clover cover crops and the role of modern plant breeding in creating new varieties that further enhance system sustainability is also discussed. Finally, as economic considerations will always impact on adoption rates, the profitability of red clover rotations in terms of silage value and yield benefits is taken into account.     

农牧交错地带种植业中的降水利用--以内蒙古伊金霍洛旗为例

农牧交错地带在我国农业生产中占有十分重要的地位,而水资源又是该地区农业发展瓶颈。以内蒙古伊金堆洛旗为例,对农牧交错地带种植业中自然降水资源的利用进行了分析,认为由于降水不合宜,地力不足,盲目开垦和水分利用率低,存在着粮豆单产严重依赖降水且产量不高的问题,并从作物,水,地力等方面提出了对策。     

Does crop insurance influence agrochemical uses under current Chinese situations? A case study in the Manasi watershed,Xinjiang

Government subsidy to crop insurance has been advocated as a policy alternative to support growth of agricultural production and farmers' income in China since the country joined the WTO. However, cautions have been raised as the crop insurance program may impact the environment negatively. This study tries to explore farmers' behaviors with regard to agrochemical use with household data applied to a simultaneous equation system consisting of disaggregated input models. It is found that decisions on fertilizer, pesticides, and agro‐film applications do have different impacts on crop insurance participation, and are influenced by the latter in different ways. It is also implied that encouraging farmers' participation in crop insurance under current low‐premium and low‐indemnity terms does not have a significantly negative impact on the environment.     

Effects of agricultural land consolidation on soil conservation service in the Hilly Region of Southeast China – Implications for land management

Land consolidation has a long history, and it has currently become one of the most extensive and well-organized human activities in China. Agricultural land consolidation (ALC) will change land use patterns, vegetation coverage, as well as the physical and chemical properties of soil through a series of engineering and biological measures that in turn affect the soil conservation service of ecosystems. This paper analyzes the effects of ALC on soil conservation service in the Hilly Region of Southeast China based on the Revised Universal Soil Loss Equation (RUSLE). The main results were as follows: (1) ALC improved the soil conservation service of cultivated land; (2) variations in the soil conservation service were strongly related to rainfall, slope, area of newly converted cultivated land, earth volume of land leveling, earth volume of topsoil stripping and backfilling, reconstructed farm roads, newly built production roads, length of new irrigation systems, newly built drainage systems, number of new dams, and newly built revetments; (3) the newly established multiple regression models used in this paper could describe the relationship between the soil conservation service and significant impact factors. This study will help researchers to better understand the interactions between land management and ecosystem service provisioning as well as provide a scientific basis for policymakers as they put forward new land management policies.     

Gender and conservation agriculture in East and Southern Africa: towards a research agenda

It is remarkable that despite wide-ranging, in-depth studies over many years, almost no conservation agriculture (CA) studies consider gender and gender relations as a potential explanatory factor for (low) adoption rates. This is important because CA demands new ways of working with the farm system. Implementation will inevitably involve a reallocation of men's and women's resources as well as having an impact upon their ability to realize their gender interests. With respect to intra-household decision-making and the distribution of benefits, CA interventions have implications for labour requirements and labour allocation, investment decisions with respect to mechanization and herbicide use, crop choice, and residue management. CA practice may impact upon the ability of households to source a wide variety of crops, wild plants, and insects and small animals for household nutrition. Gender biases in extension service design can sideline women. This paper examines the limited research to date on the interactions between CA interventions and gender in East and Southern Africa, and, based on the gaps observed, sets out a research agenda. It argues that attention to gender in CA is particularly timely given the increasing interest in CA as a means of adapting to climate change.     

The Economic Value of Soil Quality under Alternative Management in the Canadian Prairies

This paper describes a dynamic simulation model that integrates environmental and economic components of agricultural crop production systems to predict changes in soil quality and the concomitant impact on economic returns. The model is used to simulate crop yield, soil quality and economic performance of a conventional crop rotation and several alternative crop rotations in two contrasting environments in western Canada over a 50-year period. This information is used to quantify the impact of the crop rotations on soil organic carbon (SOC) and the economic value of on-site SOC changes. The estimated value of these impacts range from $0.20/t to $2.10/t of SOC/ha/yr.     

Reorienting paradoxical land use policies towards coherence: A self-adaptive ensemble learning geo-simulation of tea expansion under different scenarios in subtropical China

The expansion of cash crops has raised contradicting interests between two bureaucratic bodies (the economy-oriented one that advocates cash crop production and the conservation-oriented one that focuses on natural resources protection) in many places around the world. Recent past has saw growing efforts on the theoretical linkages between cash crop production and conservation, but the solutions to the cash cropping −related land use conflicts remain as violent controversy. Using a geo-simulation approach, this paper models the tea expansion under different policy scenarios and evaluates the effectiveness of these policies in Anji County (China), as a contribution to the scientific basis for formulating sustainable cash cropping practices and alternative land use policies. In particular, a new self-adaptive cellular automaton model based on ensemble learning (EL-CA) is developed and three policy scenarios (economy-over-conservation (EOC), conversion-over-economy (COE), and economy-balance-conservation (EBC)) are set to predict the tea expansion patterns in 2025. Results show that the EL-CA model significantly outperforms the traditional CA models based on empirical statistics. We find that the tea expansion under the EOC scenario is much more intensive than that under the COE and EBC scenarios. The most outstanding ecological consequence of tea expansion is the occupation of forests. Employing an equivalent coefficient approach, we further quantify the trade-offs between economic incomes (from tea expansion) and ecological loss (due to ecosystem service value (ESV) declines) under the three policy scenarios. In the EOC scenario, the loss in ESV far exceeds the benefit of tea expansion. Net change of ESV is higher than that of economic return under the COE. The economic benefit is approximately equal to the ecological loss in the EBC scenario. The EBC should be a socially preferred scenario, since it leads to sustainable tea expansion and minimal ecological impacts. Though the EBC scenario is a desirable choice, how to enforce these policies is an important consideration. Given the complexity in the Chinese policy context, we finally propose several possible measures to promote the coherence of paradoxical policies involving the allocation of land for cash crop cultivation.     

Estimating the joint effect of multiple soil conservation practices: A case study of smallholder farmers in the Lake Naivasha basin,Kenya

The current study seeks to assess the private benefits associated with multiple soil conservation practices (MSCPs) by estimating the marginal value of crop production that can be attributed to such practices. In areas where land degradation associated with soil erosion causes serious agri-environmental challenges such as loss of soil fertility, siltation and eutrophication, a multiple approach to soil conservation is neccessary. However, notwithstanding efforts to encourage adoption of such practices, their uptake remains generally low. Analysing the effect of MSCPs on crop productivity is one of the ways through which the incentives for soil conservation can be explored. To achieve the stated objective, the current study applied propensity score matching and exogenous switching regression techniques to cross-sectional data collected from a random sample of farm households located in Lake Naivasha basin, Kenya. Results indicate that there is a significant positive effect of implementing multiple soil conservation practices on crop productivity. However, we note that whether the additional benefits will cover the opportunity costs associated with the implementation of these practices will depend on farm specific attributes such as slope and the soil conservation effort. In cases where marginal benefits are not substantial to cover opportunity costs for implementation of soil conservation practices, intrinsic or external incentives could be necessary. Policy interventions could focus on offering technical assistance to farmers in selecting soil conservation practices that are best suited to their local condition.     

A meta-analysis of intercropping in Africa: impacts on crop yield,farmer income,and integrated pest management effects

Poverty and hunger in Africa are prevalent and will increase in absolute terms with population growth and continued land degradation. Therefore, there is a need for sustainable agricultural strategies, such as conservation agriculture (CA) and integrated pest management (IPM). Among CA practices, intercropping holds the promise of providing benefits to smallholders through increased crop yields and income as well as improved resource use. We review intercropping’s effects on crop yield, income, and output of IPM practices in Africa. On average, intercropping increases crop yields by 23% and gross income by 172 USD/ha, but effects vary significantly depending on management practices and agro-ecological factors. There was no evidence that yields and gross income for intercropping treatments increase when leguminous intercropping combinations, minimum/reduced tillage, pesticides, or fertilizers were utilized. Dual use of herbicides and intercropping practices garnered 1442 USD/ha more in gross income and yielded 1422 kg/ha more compared to those in conventionally managed fields, signifying the positive influence supplemental inputs can have on intercropping’s effects. Although IPM practices increased yields by 20%, on average, IPM systems integrated with intercropping yielded 24% less than IPM systems that did not. This meta-analysis indicates that intercropping is an advantageous sustainable agricultural practice, but that its effective implementation would depend on considering other factors such as adequate control of competing vegetation. There is a clear need for more scientific studies which examine intercropping’s role in complex sustainable agricultural systems, in order to understand its effects in differential environmental and socioeconomic situations and to optimize the practice’s transfer and benefits.