Deprived land-use intensification in shifting cultivation: the population pressure hypothesis revisited

This article provides a theoretical framework, based on optimal control theory, to analyze farm households' land‐use intensification decisions in forest‐based shifting cultivation (slash‐and‐burn) agroecosystems. The main results from the analysis generally coincide with the “Population Pressure Hypothesis” (PPH) as an important driver of soil degradation due to the so‐called “fallow crisis” or “deprived land‐use intensification” in shifting cultivation. However, the model also shows, from a supply perspective, that such a vicious circle of lower yields and greater forest land clearing may be avoided when the production elasticity of on‐farm labor outweighs the elasticity of substitution between farm labor and soil fertility. Furthermore, using data from shifting cultivating households from Yucatán, Mexico, we calibrate the effect of changes in population density. The numerical analysis suggests that by contrast to better‐off households, when population density increases, poorer shifting cultivating households' optimal labor allocation strategy is to further extensify land use by clearing more forest in the village common property land, or ejido land.     

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.     

Resource degradation and adoption of land conservation technologies in the Ethiopian Highlands: A case study in Andit Tid,North Shewa

This paper reports results from a study of resource degradation and conservation behavior of peasant households in a degraded part of the Ethiopian highlands. Peasant households' choice of conservation technologies is modeled as a two-stage process: recognition of the erosion problem, and adoption and level of use of control practices. An ordinal logit model is used to explain parcel-level perception of the threat of the erosion problem and the extent of use of conservation practices. Results show the importance of perception of the threat of soil erosion, household, land and farm characteristics; perception of technology-specific attributes, and land quality differentials in shaping conservation decisions of peasants. Furthermore, where poverty is widespread and appropriate support policies are lacking, results indicate that population pressure per se is unable to encourage sustainable land use. The challenge of breaking the poverty-environment trap and initiating sustainable intensification thus require policy incentives and technologies that confer short-term benefits to the poor while conserving the resource base.     

Determinants of farmers' indigenous soil and water conservation investments in semi-arid India

This paper investigates the determinants of farmers' indigenous soil and water conservation investments in the semi-arid tropics of India. A simple theoretical model is used to develop hypotheses about the determinants of investment under alternative factor market conditions, and these are tested using data on conservation investment from three villages. We find that conservation investment is significantly lower on leased land in two of the study villages and lower on plots that are subject to sales restrictions in one village, suggesting the potential for land market reforms to increase conservation investment. In one village, households with more adult males, more farm servants, and less land invest more in conservation, as predicted by Ihe model of imperfect labor markets; and households with more debt and off - farm income invest more, consistent with the model of imperfect credit markets. Evidence that conservation investment is affected by factor market imperfections is weaker in the other villages, where investments are much larger, suggesting transaction costs as the source of the differences between villages. Other factors that have a significant effect on investment include the farmer's education and caste, characteristics of the plot (size, slope, irrigation status, and quality ranking) and the presence of existing land investments. The results suggest the importance of accounting for differences across communities and households in factor market and agroelimatic conditions in designing programs to promote investments in soil and water conservation.     

Strategies to increase agricultural productivity and reduce land degradation: evidence from Uganda

This paper estimates a structural econometric model of household decisions regarding income strategies, participation in programs and organisations, crop choices, land management, and labour use, and their implications for agricultural production and soil erosion; based upon a survey of over 450 households and their farm plots in Uganda. Many factors have context-specific impacts and involve trade-offs between increasing production and reducing land degradation. Government agricultural extension and training programs contribute to higher value of crop production in the lowlands, but to soil erosion in the highlands. By contrast, non-governmental organization (NGO) programs focusing on agriculture and environment help to reduce erosion, but have less favourable impacts on production in the lowlands. Education increases household incomes, but also reduces crop production in the lowlands. Poverty has mixed impacts on agricultural production, depending on the nature of poverty: smaller farms obtain higher crop production per hectare, while households with fewer livestock have lower crop production. Population pressure contributes to agricultural intensification, but also to erosion in the densely populated highlands. Several household income strategies contribute to increased value of crop production, without significant impacts on soil erosion. We find little evidence of impact of access to markets, roads and credit, land tenure or title on agricultural intensification and crop production and land degradation. In general, the results imply that the strategies to increase agricultural production and reduce land degradation must be location-specific, and that there are few 'win-win' opportunities to simultaneously increase production and reduce land degradation.     

Production efficiency of Chinese agriculture: evidence from rural household survey data

A shadow-price profit frontier model is developed to examine production efficiency of Chinese rural households in farming operations. The model incorporates price distortions resulting from imperfect market conditions and socioeconomic and institutional constraints, but retains the advantages of stochastic frontier properties. The shadow prices are derived through a generalized profit function estimation. The shadow-price profit frontier is then estimated and an efficiency index based on the estimated profit frontier is computed and decomposed to household characteristics. Empirical results using data from China's Rural Household Survey for 1991 reject the neoclassical profit maximization hypothesis based on market prices in favor of the general model with price distortions. Farmers' resource endowment and education influence their response to the market restrictions, thus alter their performance in terms of efficiency. The estimated efficiency index ranges from 6% to 93% with a sample average of 62%. Households' educational level, family size and per capita net income are positively related to production efficiency. Households living in mountain areas or with family members employed by the government or state industries are relatively inefficient. Reducing market intervention, allowing right of use of farm land to be transferred among households, encouraging migration of excess farm labor, and promoting farmers' education will improve rural households' efficiency in agricultural production.     

Population pressure and soil quality in Sub-Saharan Africa: Panel evidence from Kenya

Population pressure on farmlands can have two opposing effects on soil quality. It can negatively affect soil quality due to more frequent and intensive use of farmlands, but also can induce transition of farming methods towards more intensive farming in which more fertilizer and improved seeds are used in order to make smaller farmlands more productive. In Sub-Saharan Africa, the net effect is likely to be negative given the region’s current low fertilizer use. Recent studies, however, show evidence of agricultural intensification in regions with high population pressure. It is important to analyze the extent and speed of soil degradation and its relationship with population pressure. Nonetheless, empirical studies on this topic are almost non-existent, partly because soil quality is shaped over a long time horizon, and quality panel data on this issue are rare. We use unique panel data for rural households containing soil quality information from Kenya to elucidate the effect of population pressure on soil quality. We find that population pressure reduces soil quality and also induces agricultural intensification. This suggests that although farmers are trying to mitigate the negative effect of population pressure on soil quality, the rate of soil degradation is outpacing that of intensification.     

村级尺度耕地产能空间分异及其影响因子分析

[目的]通过探究耕地产能空间分异规律与影响因子,识别地区粮食生产关键制约因素,提升高标准基本农田建设的针对性和建设效果。[方法]采用空间自相关模型刻画了村级尺度耕地产能空间分异规律,对比分析了线性回归模型和地理加权回归模型在耕地产能影响因子识别的效果,并依此划分产能提升类型区。[结果](1)海伦市耕地产能呈现中西部高北部偏低的态势,且具有较强的空间自相关特征。(2)海伦市耕地产能与黑土层厚度、出现障碍层深度、耕作距离、田块状况和质地等变量显著相关,且均呈正相关,但在空间上表现出不同程度的异质性。(3)基于地理加权回归模型的耕地产能影响因子,提出了产能保持区、耕作条件改良区、质地改良区、障碍层改良区和保护性耕作区5类耕地产能提升类型区。[结论]文章所采用的基于村级尺度耕地产能及其空间分异因素模型相关研究,能够较好揭示村级耕地产能空间分布特点、空间自相关性特征及影响因子分布特征,基于此所划分的耕地产能提升类型区较已有研究对耕地分类管理具有更精准的支撑作用。     

The future of olive groves on sloping land and ex-ante assessment of cross compliance for erosion control

Under the past Common Agricultural Policy (CAP) olive oil subsidy regime, farmers were eligible for subsidies on the basis of the amount of olive oil they produced. This led to an intensification of production, particularly on flat land, and had in most cases negative environmental effects, such as more soil erosion on sloping land and more pollution. With the decoupling of agricultural support under the newly established rules of the CAP, formalised in 2005, cross compliance measures have become obligatory.In this paper an ex-ante assessment is made of the application of cross compliance for soil erosion control (natural cover crops and terrace maintenance) in hilly and mountainous olive groves in Trás-os-Montes in Portugal. A linear programming model was developed to assess the various socio-economic and environmental effects of four different development scenarios for olive groves. The scenarios were developed on the basis of changing market prices, wage rates and subsidies; their effects included shifts towards intensification, abandonment and organic farming. Simulations considering a minimum return to labour constraint showed very high levels of abandonment, particularly in combination with cross compliance obligations. However, even without this minimum return to labour constraint, abandonment would reach more than 20% in three out of the four scenarios. The model showed that cross compliance obligations could be quite effective in reducing erosion, but that they would depress income in all scenarios as a result of higher abandonment and lower percentage shifts towards intensive systems.     

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.     

Testing the orthodoxies of land degradation policy in Swaziland

This paper explores Swaziland's National Action Programme (NAP) to combat desertification; the country's main strategy for implementing the United Nations Convention to Combat Desertification (UNCCD). It considers whether this policy tackles real problems supported by micro-level scientific evidence and local experiences, or whether it further reinforces popular orthodoxies about land degradation. Data from one case study chiefdom in Swaziland are used to test two key orthodoxies identified within the country's NAP: (1) the presentation of degradation as a neo-Malthusian problem resulting from population pressure and (2) the assumption that the poor are responsible for degradation of their environment, in particular, the over-use of forest areas and the degradation of soils. It is found that diverse rural livelihoods inherently deliver patches of degradation at the micro-level but it is not necessarily population pressure or poor people that cause the degradation. Households with varying assets simultaneously degrade and conserve different parts of the land resource through pursuing different livelihood activities. The data indicate that while the NAP focuses on mythical problems grounded in the orthodoxies, policy attention is directed away from the more serious land degradation issues affecting rural livelihoods. The findings of this study provide a more nuanced understanding of the gaps between land degradation policy, local conservation practice and environmental and livelihood outcomes, and suggest that policymakers need to evaluate more critically the outdated and simplistic degradation orthodoxies on which much current policy is based. Stronger links need to be made between scientific and policymaking communities, while more credence should be given to land users’ own knowledges, perspectives, concepts and categories surrounding issues of soil conservation and degradation. It is suggested that steps need to be taken towards the development of broadly applicable benchmarks and indicators that bring together local and scientific knowledges across levels. Without this, popularised orthodoxies will continue to provide a basis for inappropriate land policy.     

河南省耕地压力指数动态分析与预测

文章通过2004~2013年河南省耕地压力指数的直观数据,分析了2003年以来河南省耕地面积、粮食播种面积、粮食产量及常住人口的动态变化情况,发现河南省2003~2012年耕地压力指数与最小人均耕地面积变化趋势呈现出相同的波动状态,即先呈下降趋势,后在较小的波动中趋于稳定,表明2003~2012年间河南省无明显耕地压力,粮食产量足以满足人口需求。同时,文章利用灰色系统理论与线性回归分析等工具对影响河南省耕地压力指数的粮食单产、实际人均耕地面积等因素的变化进行了GM(1,1)模型的构建、修正及线性回归方程的建立,测算出以后若干年河南省耕地压力指数。研究表明,未来10年河南省耕地压力指数远小于1,耕地供应能力可以满足粮食生产需求。在肥力改善,耕地巨大生产能力得以保持的基础上,优化农业种植结构,退耕还林还草,改善农业生态,甚至开发休闲农业等,都将成为可能。     

Policy, technology, and management strategies for achieving sustainable agricultural intensification

Considerable agreement exists among researchers, development practitioners, and policymakers regarding the goals of sustainable agricultural intensification (SAI). They include: achieving agricultural productivity growth, household food security, and improved rural livelihoods and employment, while simultaneously mitigating environmental degradation. However, the multiplicity of these objectives, as well as the choice of approaches to achieving them and the site‐ and context‐specificity of specific technological and institutional interventions, assures that the research and policy challenges to achieving SAI will remain considerable. This article summarizes the contributions of the articles in this Special Issue in four areas of the literature. First, labor market constraints, the labor intensity of specific agricultural technologies and practices, and labor's substitutability, or complementarity, with other inputs are shown to widely influence their viability and related input efficiencies. Second, the articles identify specific tradeoffs and synergistic relationships that arise in the attainment of these multiple goals stemming from technologies, management practices, and policies introduced under specific agroclimatic, market, and institutional conditions. Third, these papers contribute to the literature on agricultural technology adoption by furnishing additional empirical evidence on the determinants and effects of investment behavior and adoption of specific technologies and management practices. Finally, the articles in this Special Issue emphasize that there is no single policy nor technological, management, or institutional innovation that unambiguously promotes SAI. Preferred policies must be contextualized and sensitive to initial biophysical, market, and institutional conditions.     

济宁市农村综合空心化影响因素与机制研究

[目的]基于济宁农村调研获得的66个村庄数据及501份村民现实生活状态问卷,以空心化在人口、土地、产业三方面特征为依据,构建农村综合空心化测度的指标体系,定量与定性结合研究综合空心化的影响因素与机制。[方法]文章运用熵值法计算村庄综合空心化指数,采用因子分析法和逐步回归分析方法,提取综合空心化的显著影响因素,归纳综合空心化的影响机制。[结果]济宁市农村空心化的区域差异明显,综合空心化差异低于人口和土地空心化区域差异,但高于产业空心化区域差异;经济发展、村庄规模、设施水平、土地收益等是济宁市农村发展的关键因子,其中人口劳动活力、村庄土地收益、人口土地规模是农村综合空心化的显著影响因素;特定发展阶段使农村人口劳动活力变低,受制度约束村庄土地规模相对上升;产业与就业向城镇、开发区集聚导致村庄土地收益降低,设施服务相对落后加剧人口劳动活力降低;农户的收入水平、受教育程度越高,返村意愿越弱,但其恋土情结又使宅基地退出滞缓,最终导致人口劳动活力降低,村庄土地规模相对上升。[结论]综合空心化是乡村人地关系地域系统各要素相互作用的结果。治理农村空心化,首先,要承认乡村人口减少和老龄化加剧有其必然性;其次,发挥乡村多功能价值,围绕农村一二三产融合发展,壮大特色乡村产业;第三,深化土地产权制度改革,使村民获得的权益由部分实现到充分实现。     

Farm productivity in Rwanda: effects of farm size,erosion, and soil conservation investments

This paper examines the effects of farm size, soil erosion, and soil conservation investments on land and labor productivity and allocative efficiency in Rwanda. There were several key results. First, there is a strong inverse relationship between farm size and land productivity, and the opposite for labor productivity. For smaller farms, there is evidence of allocative inefficiency in use of land and labor, probably due to factor market access constraints. Second, farms with greater investment in soil conservation have much better land productivity than average. Those with very eroded soils do much worse than average. Smaller farms are not more eroded than larger farms, but have twice the soil conservation investments. Third, land productivity benefits substantially from perennial cash crops, and the gains to shifting to cash crops are highest for those with low erosion and high use of fertilizer and organic matter. Program and policy effort to encourage and enable farmers to make soil conservation investments, to use fertilizer and organic matter, and to participate in cash cropping of perennials will have big payoffs in productivity. Land markets that allow smaller farmers to buy land could also increase aggregate productivity.     

Determinants of cropland abandonment at the parcel,household and village levels in mountain areas of China: A multi-level analysis

Cropland abandonment accompanying economic development has been observed worldwide. China has experienced a large amount of land abandonment in recent years. However, the reasons for it are not entirely clear. Although abandonment decisions are made by individual households, the underlying conditions reflect processes operating at multiple levels. Therefore, we aimed to detect the influences on land abandonment at the parcel, household and village levels. We developed and employed a multi-level statistical model using farm household survey data and geographical maps of Wulong County. Our model revealed that of the variance in occurrence of land parcel abandonment, 7% and 13% can be explained at the household and village levels, respectively, while the remnant 80% can be explained at the land parcel features itself. We found that land abandonment is more prone to occur on parcels that are on steep slopes, have poor quality soil, or are remote from the laborers’ residences. Households with less agricultural labor per unit land area showed a high probability of land abandonment. We also found a nonlinear influence of labor age on land abandonment, with households comprising middle-aged laborers having a low land abandonment probability. Parcels in villages with high elevation, far from the county administrative center or with low prevalence of leased land are inclined to abandonment. We also found, surprisingly, that the household proportion of males among its agricultural laborers did not significantly influence the occurrence of land abandonment at the parcel level, probably due to the male agricultural laborers being overwhelmingly old (average age greater than 56 years). To alleviate land abandonment, we suggest improving land tenure and transfer security to ensure stable access to the land rental market, and also improving infrastructure in remote regions.     

Mechanization in land preparation and agricultural intensification: The case of rice farming in the Cote d'Ivoire

It is critically important to intensify farming systems in sub-Saharan Africa by disseminating improved agronomic practices and increasing the application of modern inputs. One of the region's problems is that proper land preparation is difficult due to the scarcity of draft animals and the underdevelopment of the tractor rental market. Our analysis of rice production in the Cote d'Ivoire reveals that farmers who use tractors in land preparation more intensively apply fertilizer and use more labor to carefully implement proper agronomic practices, thereby raising productivity. Thus, the diffusion of tractors appears to be key to the intensification of rice farming systems in sub-Saharan Africa.     

农地流转对农户土地利用行为及效果影响探究

在农地流转的影响下,农户的土地利用结构、土地投入、土地利用效率发生了改变。通过对现有文献的总结,全面探析农地流转行为对农户土地利用行为及效果的影响,以期阐明国内外学者现有研究的不足及未来的主要研究方向。对文献的梳理得出:农地流转中,"非农化"及"非粮化"倾向明显,且土地流转市场、土地利用比较收益、政府引导是三大主要驱动力;随着农地规模的扩大,单位面积劳动投入减少,劳动产出率提高;农地流转对农地投入及农业生产效率产生何种影响,国内外学者仍存在分歧,这主要是由于现有研究不够系统深入,未考虑土地流转市场、地权稳定性、农户类型、流转方式、流转用途等因素的作用。要充分发挥农地流转对农民收入的促进作用,政府应从完善土地流转市场,提高地权稳定性出发,但如何避免流转农地"非粮化"以确保国家粮食安全仍是一个亟待解决的问题,这也是未来的一个主要研究方向。     

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.     

金口河区土地资源优化配置

合理利用有限的土地资源是实现区域可持续发展的重要内容。本文以乐山市金口河区为例,在土地利用现状和存在问题分析的基础上,应用线性规划法,根据土地总面积、人口总量、宏观计划和生态保护等约束条件,建立了土地利用结构优化模型,并对其优化结果进行了分析。研究表明:运用线性规划模型来配置土地资源,能够有效提高分析的科学性与合理性,减少不必要的人为干扰,为当地新一轮土地利用总体规划修编提供科学依据。