Impacts of the Hutan Kamasyarakatan Social Forestry Program in the Sumberjaya watershed, West Lampung District of Sumatra, Indonesia:

"This paper investigates the impacts of a social forestry program in Indonesia, Hutan Kamasyarakatan (HKm), based on analysis of a survey of 640 HKm and comparable non-HKm plots in the Sumberjaya watershed of southern Sumatra, and of the households operating those plots. The HKm program provides groups of farmers with secure-tenure permits to continue farming on state Protection Forest land and in exchange for protecting remaining natural forestland, planting multistrata agroforests, and using recommended soil and water conservation (SWC) measures on their coffee plantations. Using farmers' perceptions, econometric techniques, and propensity score matching, we investigated the impacts of the HKm program on perceived land tenure security, land purchase prices, farmers' investments in tree planting and SWC measures, and plot-level profits. A significant fraction of HKm group members are not aware of the program or fully aware of its requirements. Although farmers who are aware of the program perceive its strong effects on tenure security and land values, we found insignificant impacts on the actual purchase prices of plots. Nevertheless, our survey revealed that the HKm program has contributed to increased planting of timber and multipurpose trees. We did not find significant impacts on investments in SWC measures or on soil fertility management practices. HKm has had mixed impacts on profits, with timber trees reducing profitability because timber harvesting is not allowed and multipurpose nontimber trees contributing to increased profits. The policy implications of these findings are also discussed in the paper." from Author's AbstractRewards for environmental services, Land tenure contracts, Social forestry, Impact assessment, Land management,

Perturbative Gadgets at Arbitrary Orders

Adiabatic quantum algorithms are often most easily formulated using many-body interactions. However, experimentally available interactions are generally two-body. In 2004, Kempe, Kitaev, and Regev introduced perturbative gadgets, by which arbitrary three-body effective interactions can be obtained using Hamiltonians consisting only of two-body interactions. These three-body effective interactions arise from the third order in perturbation theory. Since their introduction, perturbative gadgets have become a standard tool in the theory of quantum computation. Here we construct generalized gadgets so that one can directly obtain arbitrary k-body effective interactions from two-body Hamiltonians. These effective interactions arise from the kth order in perturbation theory.Comment: Corrected an error: U dagger vs. U invers

Heterogeneous treatment effects of integrated soil fertility management on crop productivity: Evidence from Nigeria

This study compares the impacts of integrated soil fertility management (ISFM) on crop production with use of either mineral fertilizer or organic manure alone. We also investigate the conditions under which .ISFM technology has greater beneficial effects on yields and the factors constraining its uptake. To answer these questions, the study uses a cross-sectional, plot-level data set collected in Nigeria by the International Food Policy Research Institute and the World Bank in 2009. Using both quasi experimental matching estimators and multivariate regression approaches, it finds that overall ISFM has robustly significant positive effects on crop production. The study also finds that ISFM positively affects crop production on plots with customary tenure, sandy soils, and clay soils—conditions that are normally perceived to be less favorable for crop production. The results also show ISFM to be more effective on plots with mild erosion or no erosion. On the constraints, we find that households with limited livestock, equipment, labor, and land are less likely to use ISFM technology, and the extension services currently do not seem to be disseminating ISFM. This evidence provides strong support for efforts to promote ISFM in Nigeria and in other regions with comparable conditions, but adequate attention must be paid to the biophysical conditions of the plots and the household's access to labor endowments, livestock, equipment, and tenure conditions if this technology is to be scaled up and more widely used in Sub-Saharan Africa.Crop production, Integrated soil fertility management, matching estimators,

An econometric investigation of impacts of sustainable land management practices on soil carbon and yield risk: A potential for climate change mitigation

We investigate the impacts of sustainable land management practices on soil carbon stocks and also impacts of soil carbon on the mean and variance of crop production using econometric tools. Using a cross-sectional plot-level dataset collected from three agroecological zones of Uganda with soil carbon measured at a depth of 0 to 15 centimeters, our results have robustly shown that irrigation, fertilizers, improved fallow, crop residues, mulching, and trash lines are positively and significantly associated with higher soil carbon, corroborating results from agronomic experiments. However, we found crop rotation associated with lower soil carbon, which has also been observed in some agronomic experiments. Soil carbon has shown a significant nonlinear effect on crop production with the threshold occurring at 29.96 milligrams of carbon per hectare, above which farmers start to see significant positive effects on crop production. Furthermore, we found soil carbon to be associated with lower variance of crop production; hence, soil carbon is an indicator of crop yield loss risk (soil carbon has a risk-reducing effect). These empirical results have demonstrated strong evidence for developing countries of the potential of sustainable land management practices to enhance carbon sequestration and also the potential of soil carbon to reduce production risk. The results have implications for the role that soil carbon can play in adaptation to climate change and provision of ecosystem services.Land management, Climate change, soil carbon, Production risk, Carbon sequestration, Just and Pope stochastic production function,

Impacts of the Hutan Kamasyarakatan (HKm) Social Forestry Program in the Sumberjaya Watershed, West Lampung District of Sumatra

This paper assesses the economic impacts of the Hutan Kamasyarakatan (HKm) social forestry program in the Sumberjaya watershed in West Lampung District of Sumatra, Indonesia, which began in 2001 to provide farmer groups permits to use already deforested state Protection Forest (PF) land in exchange for protecting remaining forests, planting timber and agro-forestry trees in their coffee plantations, and using soil and water conservation measures. The study is based on analysis of a survey conducted in 2005 for 640 plots in the watershed, selected using a stratified random sample of land of different tenure categories, and their operator households, and surveys of communities with PF land and HKm groups in the watershed. We find that HKm permit holders are poorer on average than owners of private land, but have comparable wealth to users of other eligible PF land who have not applied or received HKm permits, and users of National Park (NP) land, which is not eligible for HKm. Compared to eligible non-participants, households with a HKm permit by 2005 have greater education, are more involved in producer organizations, and have better access to markets, roads and technical assistance. Many communities and households are not aware of the program or its requirements, including some of those in HKm groups. Program participants and applicants perceive that it substantially increases tenure security, land values, land investments and incomes. Econometric analysis and propensity score matching methods using the survey data provide only limited support for these perceptions, showing that the program had statistically insignificant impacts on land purchase values, soil and water conservation investments, soil fertility management practices, and profits. The program did significantly increase planting of timber and multi-purpose agroforestry trees, but these have offsetting impacts on profits, with multi-purpose trees contributing to higher profits and timber trees causing lower profits because timber harvesting is not allowed. These findings indicate that the program has potentially important pro-poor benefits, though realization of these benefits is limited by potential beneficiaries lack of access to necessary human and social capital, markets and technical assistance; lack of awareness about the program; and program restrictions that require planting of timber trees but prohibit timber harvesting.Resource /Energy Economics and Policy,

Soil and water conservation technologies: A buffer against production risk in the face of climate change?: Insights from the Nile Basin in Ethiopia

"This study investigates the impact of different soil and water conservation technologies on the variance of crop production in Ethiopia to determine the risk implications of the different technologies in different regions and rainfall zones. Given the production risks posed by climate change, such information can be used by decision makers to identify appropriate agricultural practices that act as a buffer against climate change. Using a household- and plot-level data set, we apply the Just and Pope framework using a Cobb-Douglas production function to investigate the impact of various soil and water conservation technologies on average crop yields and the variance of crop yields, while controlling for several household- and plot-level factors. Results show that soil and water conservation investments perform differently in different rainfall areas and regions of Ethiopia, which underscores the importance of careful geographical targeting when promoting and scaling up soil and water conservation technologies. We find that although soil bunds, stone bunds, grass strips, waterways, and contours all have very significant positive impacts on average crop yields in low-rainfall areas, only soil bunds have significant risk-reducing effects in these areas with low agricultural potential. We also find that irrigation and use of improved seeds have insignificant risk-reducing effects in low-rainfall areas, suggesting that—as currently implemented—these interventions may not be appropriate adaptation strategies for these environments. Regionally, in the low-rainfall areas we find significant spatial heterogeneity, with soil bunds being risk reducing in Oromiya and Amhara, and stone bunds, grass strips, and waterways being risk reducing in the Southern Nations, Nationalities, and Peoples Region. Irrigation was only risk reducing in the high-rainfall areas of Benishangul-Gumuz. These results remain robust even after controlling for the major crops grown on the plot. Results show that soil and water conservation technologies have significant impacts on reducing production risk in Ethiopia and could be part of the country's climate-proofing strategy. However, results also show that one-size-fits-all recommendations are not appropriate given the differences in agro-ecology and other confounding factors." from authors' abstractJust and Pope, Risk increasing, Risk reducing, Stone bunds, Soil bunds, Waterways, Grass strips, Contours, Soil and water conservation, Low-rainfall areas, High-rainfall areas, Climate change,

Linkages between poverty and land management in rural Uganda: evidence from the Uganda National Household Survey, 1999/00

"This study investigates the impacts of rural poverty on farmers' land management decisions, crop production and incomes, based upon analysis of data from the 1999/2000 Uganda National Household Survey. We find that the impacts of rural poverty on land management, crop production and income depend upon the type of poverty (i.e., what asset or access factor is constrained) and the type of land management considered...Our results suggest that improvement in smallholders' access to land, other assets, education, extension, market information, credit, roads, and off-farm opportunities can help to break the downward cycle of poverty and land degradation, and put farmers on a more sustainable development pathway. Access to land (area and quality), other assets, education and off-farm opportunities appear to be particularly important in addressing poverty directly, while other interventions are likely to have more indirect impacts, as they influence land management, crop choice, and other livelihood decisions. Given the importance of land as the major asset owned by poor rural households in Uganda, investing in land quality maintenance and improvement is a critical need. However, we found low marginal returns to investments in organic or inorganic fertilizer and other land management practices, suggesting that it will be difficult to get farmers to make such investments in the present environment. Improvements in the market environment as well as development of more profitable land management technologies appears essential to address this need." from Authors' Abstract

Impacts of inventory credit, input supply shops, and fertilizer microdosing in the drylands of Niger:

"This study investigated the impacts of access to inventory credit, input supply shops, fertilizer microdosing demonstrations, and other factors on farmers' use of inorganic fertilizer and other inputs in Niger and on crop yields. We found that access to inventory credit and input supply shops has increased the use of inorganic fertilizer and seeds and that microdosing demonstrations have increased the use of inorganic fertilizer. Ownership of traction animals and access to off-farm employment have also contributed to the use of inorganic fertilizer, while larger farms use less fertilizer and labor per hectare. The impacts of these interventions and technologies depend on the crop mix. Inorganic fertilizer has a positive impact on millet and millet–cowpea yields when applied using microdosing, with an estimated marginal value-cost ratio greater than 3 for those crops indicating significant profitability. By contrast, microdosing has a negative impact on yields of the millet–sorghum–cowpea intercrop, suggesting that microdosing should not be promoted when sorghum is part of the crop mix. However, better access to input supply shops has contributed to higher yields of the millet–sorghum–cowpea intercrop. The predicted effect of inventory credit on farmers' income as a result of increased inorganic fertilizer use is an increase of 5,000 to 10,000 FCFA per hectare (about US$10 to US$20 per hectare in 2005) in millet or millet–cowpea production. Similarly, being 10 km closer to an input supply shop is predicted to increase farmers' income by 3,200 to 4,500 FCFA per hectare. These benefits do not take into account the impacts of the interventions on seeds or other inputs, which are also generally positive. The positive impacts are linked to the use of fertilizer microdosing, which has increased the productivity of fertilizer use in millet and millet–cowpea production, indicating synergies among the various interventions. They are also linked to these specific crops, because we found less favorable impacts of these interventions for the millet–sorghum–cowpea intercrop and for peanuts. Other interventions that could help to boost the use of inputs and productivity include promotion of improved access to farm equipment and traction animals and promotion of higher-value crops such as hibiscus. Further research on these topics appears warranted. Research on the implications of interventions on land degradation would also be useful." from Author's AbstractFertilizer microdosing, Inventory credit, Warrantage, Input supply shops, Drylands, Land management,

From the ground up: Impacts of a pro-poor community-driven development project in Nigeria

Agricultural development projects, Economic development, Poverty,

Policy options for increasing crop productivity and reducing soil nutrient depletion and poverty in Uganda:

"This study was conducted with the main objective of determining the linkages between poverty and land management practices in Uganda. The study used the 2002/03 Uganda National Household Survey (UNHS) and more focused data collected from a sub-sample of 851 households of the 2002/03 UNHS sample households. We found that farmers in Uganda deplete about 1.2 percent of the nutrient stock stored in the topsoil per year, which leads to a predicted 0.31 percent reduction in crop productivity. The value of replacing the depleted nutrients using the cheapest inorganic fertilizers is equivalent to about 20 percent of household income obtained from agricultural production. Econometric analysis of the survey results provides evidence of linkages between poverty and land management practices. Land investments increase agricultural productivity and income and conserve natural resources. Many inputs and land management practices increase crop production per acre. We observed an inverse farm size – crop productivity relationship but a negative association of farm size and per capita income. Education of female household members has generally a limited impact on land management, while male education is associated with greater use of inorganic fertilizer. Both female post-secondary and male primary and secondary education are associated with higher crop productivity. Larger families use more erosive practices but realize higher value of crop production per acre but have lower per capita income. Access to financial capital, markets and roads has limited effect on land management. However, access to financial capital and non-farm opportunities increase crop productivity and per capita household income and access to roads contributes to higher per capita household income and less soil nutrient depletion. These results support the Uganda government poverty reduction strategy through building rural roads, and increasing access to financial capital and non-farm opportunities. Both the traditional and the new agricultural extension program increase use of fertilizer and crop productivity, suggesting that investment in extension services could significantly contribute to agricultural modernization and poverty reduction. The results suggest the need to give incentives for technical assistance programs to operate in remote areas, where access to extension services is limited. Perennial crop producers deplete soil nutrients more rapidly, implying the need to promote measures to restore soil nutrients in perennial (especially banana) production areas. We find no significant differences in crop productivity or income per capita associated with differences in land tenure systems. Our findings suggest that customary land tenure, which is the most common form of tenure, is not a constraint to improvements in land productivity or use of sustainable land management. Overall, our results provide general support for the hypothesis that promotion of poverty reduction and agricultural modernization through technical assistance programs and investments in infrastructure and education can improve agricultural productivity and help reduce poverty. However, they also show that some of these investments do not necessarily reduce land degradation, and may contribute to worsening land degradation in the near term. Thus, investing in poverty reduction and agricultural modernization is not sufficient to address the problem of land degradation in Uganda, and must be complemented by greater efforts to address this problem." Authors' Abstract