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.     

基于主成分分析的山西省农业循环经济发展水平评价研究

[目的]农业循环经济是我国农业可持续发展的必由之路,对农业循环经济发展水平的评价是该领域研究的关键。[方法]构建包含社会、经济和生态效益的农业循环经济评价指标体系的基础上,运用主成分分析法结合线性回归方程对山西省2001~2016年农业循环经济发展水平进行评价和分析。[结果](1)山西省农业循环经济发展水平的评价因素可归纳为生产资料集约水平、资源修复水平和土地集约水平3方面。(2)山西省农业循环经济在2001~2016年总体呈现上升趋势;并分为两个发展阶段,2001~2009年农业循环经济发展低水平阶段和2010~2016年农业循环经济发展上升阶段。(3)2010年之后山西省转变传统农业发展方式、实现农业循环经济取得一定成效,生产资料集约水平是促使山西省农业循环经济发展提升的主要动力。[结论]山西省转变传统农业发展方式,提升农业循环经济发展水平,使农业走可持续发展道路注重生产资料的集约是关键,可以从控制化肥、农药、农膜投入量,提升其有效利用系数等方面入手;其次要提升资源修复水平,利用秸秆还田的形式增加废弃物利用率,增加水土流失治理面积;并提高土地利用率。     

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.     

Fostering integrated land and water management approaches: Evaluating the water footprint of a Mediterranean basin under different agricultural land use scenarios

In the Genil River Basin (southern Spain), agriculture is the greatest pressure on freshwater demand. Furthermore, water degradation caused by soil erosion is becoming a key environmental concern. This study aims to assess the water-related impacts of agriculture combining the use of an ecohydrological model (SWAT) with a spatiotemporal water footprint assessment to evaluate the current status of streamflow (blue water), soil water (green water) and the assimilability of sediments by streamflow (grey water footprint). The Common Agricultural Policy (CAP) requires farmers to adopt certain agricultural practices that are beneficial for the environment. Such practices could affect the conditions of available land and water resources. Because of the importance of applying the best land management practices for the maintenance of sustainable water resources, the study also infers probable water availability and water pollution level changes under different post-2013 CAP scenarios. The Genil streamflow is highly regulated, and, as a result, it is hard to discern significant changes (p < 0.05) under the proposed scenarios. However, there is a shift with afforestation measures from unproductive (i.e., direct soil evaporation) to productive water (i.e., evapotranspired water from agricultural and natural areas, excluding non-growing periods) consumption. The probability of annual evapotranspiration from natural areas being greater in afforestation scenarios than in the baseline scenario is 0.70 to 0.88, whereas the likelihood of soil water evaporation being lower is 0.60. Evapotranspiration in natural areas increases by about 521% from September to May under afforestation measures compared with the baseline scenario, whereas soil water evaporation decreases by 30% in winter. The grey water footprint and water pollution level decrease by 19% and 9%, respectively, with the highest streamflow conditions under afforestation as opposed to current conditions. However, water pollution levels of suspended solids greater than 1 indicate that the river flow is not capable of assimilating the existing sediment loads. Since land use changes and agricultural practices have a major impact on water resources, the post-2013 CAP reform can provide environmental benefits for water allocation and mitigation of water pollution. However, further efforts are required to better align the policy goals of the CAP and the Water Framework Directive.     

基于生态系统服务改进的中国各地农业生态效率研究

[目的]为提高全国农业资源利用率,推动建立资源节约型与环境友好型的可持续"两型农业",对中国农业生态效率展开研究发现,农田生态系统服务是农业生产的重要产出,但在当前生态效率研究中未得到充分体现。文章通过量化农田生态系统服务价值,有利于权衡农产品供需关系,更好以农田生态系统给人类社会带来的福利为目标来开展农业生产。[方法]文章将生态系统服务价值作为期望产出之一,将全国划分为东部地区、东北地区、中部地区和西部地区的4个农业效率研究区域。运用非期望产出数据包络分析方法,计算2014年中国30个省(市、自治区)的农业生态效率,并分析其主要影响因素。[结果](1)中国农业生态效率整体水平良好,平均值为0.945,在空间上表现为东部东北西部中部的空间分布格局。(2)影响全国农业生态效率的关键因素为土地投入、机械投入、化肥投入和水资源投入。农业生态系统服务指标与农业生态效率呈正向相关。土地、农药、劳动力、机械、水资源、化肥、农膜和能源投入、农业产值及碳排放均与之呈负向相关。其中农药投入是最为显著的抑制因子,控制农药投入是提升全国农业效率核心因素。(3)中国农业生态效率空间分异格局是多层影响因素叠加而成,中国农业生态效率损失的原因主要在于资源要素消耗的过量与农业碳排放过多。[结论]中国农业生态效率整体上发展较好,但各省市的农业生态效率水平存在较大差异,仍有上升的空间。从投入产出冗余角度来看,目前中国农业生态效率损失的原因主要在于资源要素消耗的过量与农业碳排放过多。在发展中着重加大区域对农业土地的开发投入、推广机械科学技术、减少化肥等污染物投入与提高水资源的利用效率,发展用水技术,保障农业的可持续发展。     

Conditions for the adoption of agro-ecological farming practices: a holistic framework illustrated with the case of almond farming in Andalusia

Agricultural landscapes offer unique habitats for many species. Because agriculture is a major land use worldwide, changes in farming practices can have major repercussions for biodiversity. Particularly in Western Europe, ongoing intensification and scale enlargement but also land abandonment and poor agricultural practices leading to land degradation form a major threat to agrobiodiversity. Agro-ecological farming practices are suggested as an alternative way of farming in order to conserve and enhance biodiversity. Yet knowledge about what factors explain farmers’ adoption of agro-ecological farming practices is fragmented and incomplete. In this paper, we offer a holistic framework that specifies these factors and how they are interconnected. The framework is illustrated and refined by means of a case study analysis of almond farming in Andalusia. The chosen case represents a specific localized farming practice that currently negatively impacts biodiversity but for which agro-ecology forms an attractive alternative regarding biodiversity. The case study demonstrates that our framework offers a useful tool to systematically identify the different factors that affect agro-ecological farming adoption, interlinkages between factors and particularly the more structural barriers to agro-ecology.     

Land management for erosion prevention: A case study for a Turkish nature reserve

As a result of landslides and soil erosion, a substantial amount of soil has been lost in Turkey. Particularly, fertile lands have long been faced with the threat of erosion, largely as a result of traditional (unplanned) land use practices. This threat is more evident in the Black Sea Region with its rough topography and rainy climate. The basic reason for this threat is the lack of organization in land use planning and control. Although proposals, in the context of this requirement, are included in national development plans, they have not been implemented. Accordingly, in this study research based on spatial data evaluation was carried out for Sera Lake located in Akcaabat, Trabzon, Turkey. For this purpose, temporal area, depth and volume changes of the lake were determined by utilizing topographic maps, aerial photographs and hydrographical measurements. To evaluate determined changes in the size of the lake and to produce suggestions to legislators for required sustainable land management activities, information on land use/cover types, land ownership and climate in the vicinity of the lake was utilized. As a result, it was determined that the area, depth and volume of the lake were significantly decreased during the last decades, as a consequence of erosion mainly caused by traditional land use practices; thus, the lake is threatened with the danger of extinction due to erosion. Precautions required for the alleviation of erosion and other adverse environmental effects which largely seem to be caused by harsh physical properties (caused basically by topography) of the region were discussed. In support of the information inherent to the region, traditional arable land use was logically determined as the basic non-natural factor (which is directly prone to erosion) to be rearranged in the context of sustainable land management. In this context, beyond nationwide actions (national agricultural policy and Soil Protection and Land Use Law), which may provide the required land management tools in the long term, it is proposed that planning and accordingly land management activities specific to the study area (Sera Valley) should immediately be commenced in close collaboration with the related public (owners or farmers). However, behaviours of different types of land users (engaged in commercial, subsistence and semi-subsistence farming) and also high number of owners and/or farmers (caused by small pieces of land parcels owned/used in shares) make the desired collaboration almost impossible. This socio-economical problem may be solved by further developing the current land registry and cadastre system in terms of customary land use rights, land use/cover changes and updating procedures.     

2023年土地科学研究重点进展评述及2024年展望 ——土地工程与信息技术分报告

研究目的：归纳分析2023年国内外土地工程与信息技术领域的研究进展,展望研究趋势。研究方法：文献分析法。研究结果：国内研究主要集中在土地综合开发模式与运行机制、全域土地综合整治的潜力机制及路径、碳中和背景下的土地复垦与生态修复、土壤—植物—微生物模式下的复垦土壤重构、国土空间生态修复差异化分区与格局构建、土地信息智能化监测技术与信息提取方法、数字化国土空间规划技术、基于GIS的土地管理技术。国外研究主要集中在农业用地土地整理模式、基于土壤改良的矿区土地复垦、土壤—植物—微生物协同修复作用机制、基于社会经济和生态指标的生态修复、土地信息监测与预测技术、基于人工智能的土地规划技术、土地管理系统优化技术。研究结论：2023年土地工程与信息技术在全域土地综合整治、土地复垦与土壤重构、国土空间生态修复、土地信息监测与管理技术等方面取得了一定进展。结合当前科技需求,2024年及未来重点关注山水林田湖草沙一体化保护和系统治理、全域土地综合整治和国土空间生态保护修复、碳中和目标下的矿区土地复垦、乡村振兴背景下的土地集约利用和低效用地治理、土地信息可视化技术和土地信息智能化处理技术。     

Implications of CAP reform for land management and runoff control in England and Wales

WTO negotiations, as well as problems associated with intensive agriculture, such as overproduction, dependency on high levels of subsidies, diffuse pollution, soil degradation and loss of wildlife, have led to a reconsideration of agricultural policies in Europe. In April 2005, the new common agricultural policy (CAP)-reform came into force in the United Kingdom, decoupling financial support to farmers from agricultural production. Farm income support payments are now linked to compliance with standards (cross-compliance rules) which protect the environment, animal health and welfare. In the light of these policy changes, semi-structured interviews were carried out with 36 farmers in five catchments in the UK to explore interrelationships between CAP-reform, agricultural land management and runoff-related problems. Results from three catchments are specifically highlighted because of their relevance for soil policy.The CAP-reform appears to facilitate and accelerate changes in the agricultural sector that were already happening. It is likely that upland livestock farms will extensify further, which will reduce environmental burdens such as diffuse pollution, soil compaction and runoff. The uptake of agri-environment schemes by individual farmers has increased since the CAP-reform. However, additional impacts are limited as there is a tendency among participants to enter these schemes based on existing features and practices.Although most farmers interviewed for this study appear to recognise the need to reduce soil erosion and diffuse pollution, they are less convinced they should be held responsible for controlling storm-water runoff from farmland that might contribute to flooding downstream. However, there are opportunities to achieve several objectives simultaneously, including improved soil management, runoff control and reduced pollution. Lessons can be learned from farmers’ opinions about CAP-reform, from successful interventions that aimed to reduce soil erosion and diffuse pollution, and also from failures. Recommendations are made for improvements to the current agri-environment schemes and to promote land management practices with less environmental burden.     

Measuring soil quality dynamics A role for economists, and implications for economic analysis

Measuring soil quality is extremely difficult, yet it has clear economic importance. In particular, there is a great deal of empirical interest in the dynamics of soil quality evolution when land managers respond to policies and other incentives. Yet current methodologies for measuring changes in agricultural land quality are largely static and rely heavily either on incomplete measures such as proxy variables, or ad hoc indexes of selected soil characteristics. Moreover, much empirical work relies on static econometric techniques or simulation models. In this paper, we develop a means to infer soil quality changes from input and output data using a dynamic production function model. Using data from field experiments, we estimate the model in a way that allows the recovery of a dynamic measure of soil quality whose evolution depends on variations in management practices. Our methodology and findings will help provide firmer empirical foundations for analyses of the economic implications of land degradation and the soil quality implications of agricultural policies.     

Food Insecurity,Soil Degradation and Agricultural Markets in West Africa: Why Current Policy Approaches Fail

The agricultural sector in West Africa is not at present capable of meeting the growing demand for food for its population and of reversing unfavourable trends in soil degradation. We argue that integrated soil management is an essential condition for sustainable agricultural development in the many regions in West Africa where population pressure forces an intensification of land use. Such an approach combines improved soil-moisture storage measures, and the use of organic and inorganic fertilizers and soil amendments. The synergetic effects which could result from this combination are indispensable for achieving the productivity increases needed to cope with the pressure of population. Current (neo-liberal and ecological-participationist) policy approaches are unable to realize the transition towards integrated soil management technologies. The time lags involved in learning to use new technologies, in the adaptation of technologies to local circumstances, and in reaping the benefits of soil fertility investments call for (at least temporary) support of agricultural incomes.     

Determinants and impact of sustainable land management (SLM) investments: A systems evaluation in the Blue Nile Basin,Ethiopia

Ongoing debate over water management along the Blue Nile and land degradation in Ethiopia emphasizes the need for efficiency gains in agricultural production through sustainable land management (SLM). However, previous SLM studies overlook the tradeoffs involved in maintaining SLM investments over time. We address this limitation by combining a household survey that evaluates the economic impacts of SLM investments and maintenance, with a hydrological model that explores location‐specific infrastructure effects. We then use a multi‐market model to evaluate the impacts of alternative SLM investments on agricultural production, prices, and incomes over time. Analysis suggests SLM investments must be maintained for at least seven years to show significant increases in value of production, and that terraces on moderate and steep slopes are most effective in increasing agricultural yields. However, the benefits of terracing do not outweigh the cost of foregone off‐farm labor opportunities, nor compensate for lower agricultural prices from increased supply. Thus, SLM investments must be paired with other input and infrastructure investments, as well as subsidies for initial labor costs, in order to incentivize adoption and long‐term SLM maintenance.     

A comparative multidimensional evaluation of conservation agriculture systems: A case study from a Mediterranean area of Southern Italy

To avoid the current paradoxes of the global agro-food system it is necessary to define and implement a viable agricultural sustainable model, combining satisfaction of food needs and land preservation. A possible solution can be found in a holistic production system consistent with a sustainable development model, designed to satisfy diverse “local” economies. The conservation agriculture (CA) could be a part of this model, as it includes a set of best practices available to preserve agrarian soil and its biodiversity. Briefly, we cover the CA background in Europe followed by the evaluation of its impact in terms of private/public interest, using the sustainability’s metric.To test the viability of a model based on CA in “local conditions”, we compare economic performance of different conservation practices (i.e. minimum and no tillage) to that of conventional agriculture in a typical Mediterranean environment – Collina Materana – in Southern Italy (Basilicata region). Our findings suggest that: i) CA can actually be a viable alternative to conventional systems; ii) in Mediterranean agricultural areas CA has yield advantages especially during dry years, when conservation techniques increase water supply to crops; iii) public support is needed to direct farming choices in fact without financial incentives these practices would be not widely accepted and diffused; iv) European policy makers have to recognized the positive benefits of CA and pay them as ecosystem services in the framework of Good Agricultural Environmental Conditions and the present CAP subsidies.     

农田污染对粮食生产的影响研究——以四川为例

作为农业生产的根本,农田质量对于粮食生产而言至关重要,因此农田污染的相关防治已经成为我国农业可持续发展、农产品安全以及我国生态环境保护的重要措施。目前我国农田污染主要特征为农田污染物成分复杂,农田污染程度不断扩大。同时由于农田污染导致土壤肥力下降进而导致相关农作物的产量以及品质不断下降。文章以四川省为例,探究农田污染对粮食生产的影响,结果发现,目前四川省农田污染主要来源于农药化肥的不合理使用,水体以及土壤受工业废水污染严重,畜牧业废弃物污染等。农田污染导致可耕种土地面积不断减少,粮食生产受到严重影响。基于此,该文针对四川省农田污染现状提出农田污染综合立体防控策略,并在此基础上通过合理规划农业生产,减少农药化肥使用量,提高生物防治在病虫害防治当中的比例等措施减少农田污染对粮食生产的影响,以期为我国农田保护以及粮食生产提供一定的理论以及政策依据。     

Impact and implications of price policy and land degradation on agricultural growth in developing countries

In many developing countries, a high proportion of the population resides and works in rural areas. Agriculture is the dominant sector in rural areas and has the greatest concentration of poverty: landless workers, small tenant farmers, and small farm owners. Thus, any development strategy that is directed towards increasing employment and alleviating a country's hunger must concentrate on sustainable agricultural growth. Historically, economic development in most countries has been based on exploitation of natural resources, particularly land resources. Soil erosion and land degradation have been serious worldwide. Due to reasons such as high population pressure on land and limited fossil energy supplies, land degradation is generally more serious in the developing world. Empirical studies show that soil erosion and degradation of agricultural land not only decrease the land productivity but they can also result in major downstream or off-site damage which may be several times that of on-site damage. In promoting industrialization, governments of many developing countries adopt a package of price and other policies that reduce agricultural production incentives and encourage a flow of resources out of agriculture. Increasing evidence shows that these policies cause a substantial efficiency or social welfare loss, and a great loss in foreign exchange earnings. In addition, a World Bank study on the effect of price distortions on economic growth rates concluded that neither rich resource endowments, nor a high stage of economic development, nor privatization are able to make up the adverse effects caused by high price distortions. This analysis is primarily concerned with identifying the factors that determine the agricultural production growth rate and in testing the effects these factors have on agricultural growth in developing countries. Specifically, this study involves statistical estimation of an aggregate agricultural growth function based on cross-country data for 28 developing countries. Special attention is devoted to land degradation and agricultural pricing policy, and to the policy implications resulting from the effects these variables have on agricultural and food production growth. The overall results of this study show that price distortions in the economy and land degradation had statistically significant negative impacts while the change in arable and permanent land was positively related to the growth of agricultural production and food production in 28 developing countries from 1971 to 1980. These results emphasize the importance of ‘getting prices right’ and implementation of sustainable land and water management practices if future growth in food and agricultural output is to be realized and sustained in developing countries.     

面向SDGs的土地可持续利用目标、挑战与应对策略

研究目的:基于联合国2030可持续发展目标(SDGs),分析土地可持续利用的目标以及中国所面临的形势与挑战,并提出应对策略,为可持续发展的实现提供路径支持。研究方法:文献研究法。研究结果:土地利用是人类、土地单元和土地利用方式三者相互影响与制约的过程,会深刻影响2030年可持续发展目标的实现;在17个SDGs中,有7个目标与土地利用相关,可归纳为高效和集约利用土地、保护和改善土地生态环境、被社会所接受三大目标,以及提高农用土地生产能力、促进工业土地集约与转型利用、建设安全和包容城镇、防治土地污染、恢复生态系统和防治土地退化、消除贫困和实现土地产权安全7项具体目标;面对SDGs的土地持续利用目标,中国在耕地保护、工业用地转型升级、土地污染治理、土地生态修复等方面还面临诸多挑战。研究结论:为推进面向SDGs的土地可持续利用,需要构建本土化监测指标体系,自然资源相关规划与政策的制定要反映土地可持续利用的目标,以土地制度改革助推土地可持续利用,重视土地科技创新,并加强利益相关群体的参与和合作。     

Changes in Brazil’s Forest Code can erode the potential of riparian buffers to supply watershed services

In Brazil, the Forest Code requires landholders to maintain fixed-width buffers of native vegetation along watercourses – legally called Areas of Permanent Preservation (APPs). In 2012, agricultural activities started to be partially allowed in APPs, but only if best management practices on soil and water conservation are adopted and if a narrow buffer strip with native vegetation is restored adjacently to the watercourse. In this paper, we present a modeling framework to investigate the capacity of legal compliant APPs to supply watershed services (erosion control and stream bank stabilization) in a 2,200 ha watershed in São Paulo State, Brazil. Our results suggest that the narrower the riparian buffer the lower the control of soil erosion dynamic within APPs, and that riparian buffers smaller than 8 m can act as a source of sediments to streams. The adoption of best management practices can contribute to controlling soil erosion within APPs but the presence of native forests in the first 15 m is necessary to guarantee equivalent protection to streams when compared to APPs completely covered by forests. Moreover, we observed that forest restoration within APPs helped to reduce the average soil loss of the watershed by only 20 %, compared to a reduction of 55 % when best practices are implemented in all watershed agricultural areas. We conclude that (i) the reduced requirements for APP restoration may contribute to stream sedimentation, which will likely affect the supply of watershed services by stream ecosystems; (ii) the implementation of best management practices in APPs will not have the same effect as native forests to reduce stream sedimentation; and (iii) the adoption of best management practices in all agricultural production areas – and not only within APPs as required by law – is the best strategy to promote the supply of watershed services to society.     

Adoption of agricultural land management technologies by smallholder farmers in the Jos Plateau,Nigeria

Against a background of growing concern about the adverse effects of agricultural land degradation due to accelerated soil erosion, nutrient depletion and high population pressure, farmers in the Jos Plateau, Nigeria have adopted biological and structural land management practices, though the degree of adoption of such practices varies from one farm household to another. This study, based on a survey of 150 farm households, employed a stepwise multiple linear regression model to analyse the factors significantly influencing the adoption of land management technologies. The results of the analysis revealed four variables, namely, extension service, agricultural labour force, accelerated soil erosion and out-migration, explaining nearly 90% of the variation in the range of land management technologies adopted. The first three of these variables have positive influences on adoption. Extension service appeared to be the strongest, impacting on skills in the agricultural labour force. Policy recommendations are made in line with the findings of the analysis.     

基于DEA模型的山东省农地利用经济效益分析

山东省农地面积较广,利用类型丰富,农地的合理利用对推进山东省农业经济发展及土地资源的可持续发展具有重要意义。文章阐述了山东省农地利用状况,从自然因素、土地投入、农业土地利用结构、农业从业人员素质、农产品市场意识及经营手段等方面探讨影响农地利用经济效益的因素,通过构建DEA模型,对农地利用经济效益进行应用分析,并提出加大农业用地投入和建设、优化农业用地结构和规模、强化市场经营意识和管理等提高山东省农地利用经济效益的对策建议,以期为山东省土地合理规划利用提供理论依据。