Browsing by Subject "Bodenschutz"

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An economic analysis of the implementation options of soil conservation policies
(2008) Schuler, Johannes; Dabbert, Stephan
The objective of this study is to analyze the economic and agricultural aspects of the implementation of soil conservation programmes and to suggest appropriate measure-instrument combinations for efficient soil conservation as a decision support for the implementation of soil conservation policies. Emphasis is given to the resource and institutional economics of soil conservation. In the empirical part, the efficiency of policy options is analysed using the example of a region in north-eastern Germany based on model calculations. After an introduction to the topic of soil functions and soil degradation definitions, the implementation concepts for soil protection measures at the international and national level are described. Based on the theoretical economic analysis of soils as a natural resource, the existing property rights, the public good characteristics of soils and the resulting externalities lead to the conclusion that market failure does exist. Therefore, the non-market coordination of soil use is justified. A cost-effectiveness analysis was derived based on the theory of ?safe-minimum-standard? for the appropriate assessment of the implementation options of soil conservation policies. A fuzzy-logic-based method, which is based on an expanded Universal Soil Loss Equation approach (USLE), was applied for the assessment of soil erosion risk in the sample region. The approach considers both the natural conditions and the characteristics of the cropping practice. The very detailed description of the cropping practices allowed for the specific assessment of erosion relevant effects. This, in combination with the high detail site descriptions provided this study with a very precise regional approach. The regional decision-support system MODAM (multi-objective decision support tool for agro-ecosystem management) was applied for the assessment of the economic and environmental impacts of different policy options. The policy scenarios examined include a CAP reform scenario with decoupled payments in accordance with the proposed conditions of the year 2013. This scenario was used as the reference scenario for the other possible scenarios of soil conservation policies. The three main scenarios for the policy options are 1) a non-spatially oriented, 2) a spatially-oriented incentive programmes for reduced tillage practices and 3) a regulation scenario that prohibits the cultivation of highly erosive crops (row crops) on erodible soils. The prohibition of row crops on highly erodible soils led both to lower on-farm costs and lower budget costs in comparison to the incentive programmes for reduced tillage. All three scenarios had comparable reduction in soil erosion. Based on the modeling results the ban on row crops on highly erodible sites is therefore the preferable option in terms of the cost-effectiveness ratio. The inclusion of transaction costs in this study helps expand the scope of policy analysis, for the total costs of a policy would be underestimated if only the budget costs for the direct payments to farmers were considered. Transaction costs understood as a cost for the (re-) definition and implementation of property rights can reach substantial amounts and reduce the total efficiency of a policy. The results of the qualitative analysis of the transaction costs of the study policy options also supported the option of row crop regulation on highly erodible soils. A model that serves as decision support for both the economic and agricultural aspects of soil conservation had been successfully developed in this study. Different policy options were analysed for a cost-effective solution of soil conservation programmes. Based on the final discussion on the involved transaction costs, the regulatory approach (a spatially-focussed ban on row crops) was shown to be the most cost-effective option with potentially lower transaction costs. The main criteria for a cost-effective policy design are high efficiency in both the agricultural measures (practices) and the spatial correlation between the programme area and the high erosion risk areas. Incentive programmes in combination with less effective agricultural practices showed a worse cost-benefit ratio for the sample area than the regulation approach, which is based on more effective agricultural practices.
Crop yield and fate of nitrogen fertilizer in maize-based soil conservation systems in Western Thailand
(2021) Wongleecharoen, Chalermchart; Cadisch, Georg
The increase in food demand and land scarcity in high-potential lowland areas have forced cropping intensification with a transformation of land use from subsistence to permanent agriculture in remote hillside in Southeast Asia. This change and inappropriate land use are the prime cause of soil degradation by erosion, which have negatively affected the agricultural systems productivity and sustainability in Thailand. Therefore, vulnerable land in sloping terrain is classified as unsuitable for continuous production of arable crops unless conservation measures are introduced to stabilize the landscape. Even though conservation practices can stabilize sloping land, farmers have not been widely adopted the measures due to various constraints, such as crop area loss and crop-tree competition. To improve land use management, a two-year study (2010-2011) was conducted at the Queen Sirikit research station (13°28’N, 99°16’E), Ratchaburi Province, Thailand, on a hillside with a slope of around 20%. The treatments consisted of (T1) maize (Zea mays L.) mono-crop under tillage and fertilization, (T2) maize intercropped with chili (Capsicum annuum L.) under tillage and fertilization, (T3) maize intercropped with chili, application of minimum tillage plus Jack bean (Canavalia ensiformis (L.) DC) relay cropping and fertilizer application, (T4) maize intercropped with chili, application of minimum tillage with Jack bean relay cropping and fertilizer application plus perennial hedges of Leucaena leucocephala (Lam.) de Wit, (T5) as T3 but without fertilization, and (T6) as T4 but without fertilization. There was an additional plot of chili sole cropping to calculate the land equivalent ratio (LER). The first part of the study evaluated yield performance and nitrogen use efficiency (NUE) of crops using the 15N isotope technique under diverse fertilized cropping systems during the first year. Maize grain yields were lower in T2 (3.1 Mg ha-1), T3 (2.6 Mg ha-1) and T4 (3.3 Mg ha-1) than in the control (T1) (6.7 Mg ha-1). The total returns from maize and chili yields were 1,914, 5,129, 3,829, 3,900, 3,494, and 2,976 USD ha-1, for T1, T2, T3, T4, T5 and T6, respectively. Higher economic returns in mixed crop systems, by selling both maize and chilies, compensated for the maize area loss by intercropping. Maize 15NUE was highest in T2 (53.5%), being significantly higher than in T1 (47.0%), T3 (45.5%), and T4 (45.7%). Overall system’s NUE in T2 (56.8%) was comparable to T1 (53.8%) and T4 (54.5%) but significantly lower in T3 (48.6%). Minimum tillage and hedgerows (despite their positive filter effect) did not increase NUE but adversely affected maize growth during the establishment phase. The second part of the study examined nitrogen fertilizers fate and quantified partial nitrogen budgets at plot level over two cropping seasons for various maize-based cropping systems with or without fertilizer application. Overall plant uptake of fertilizer 15N applied to maize was 48.6-56.8% over the first season, while residual fertilizer 15N recovery of plants was only 2.3-4.9% over the subsequent season. The quantity of applied labelled N remaining in the soil at the end of season 1 and season 2 was 6.2-28.1% and 7.7-28.6%, respectively. Thus, 60.0-76.0% in season 1 and 12.7-31.3% in season 2 of the applied fertilizer 15N were accounted for within the plant-soil system. Consequently, 24.0-40.0% and 12.9-16.1% of labelled fertilizer N were not accounted for at the end of season 1 and season 2, respectively. The derived N balance over two years revealed severe soil N depletion under T1 (-202 kg N ha-1), T5 (-86 kg N ha-1) and T6 (-48 kg N ha-1), and a slightly negative N budget under T2 (-5 kg N ha-1). In contrast, T3 (87 kg N ha-1) and T4 (62 kg N ha-1) had positive N balances. The increase of N input via additional N fertilizer applied to chili and symbiotic N2 fixation of legumes, and the reduction of N losses by soil erosion and unaccounted fertilizer N (probably lost via leaching, volatilization and denitrification) were the main factors of the positive N balances under maize-chili intercropping systems with conservation measures and fertilization (T3 and T4). Maize yield decline under T1, T2, T5 and T6 in season 2 was related to negative N balances, while maize yield increase under T3 and T4 was related to positive N balances. However, maize-chili intercropping with fertilization had some advantage (LER > 1.0) relative to sole species cropping. Moreover, total returns from crop yields in season 2 of all maize-chili intercroppings (1,378-1,818 USD ha-1) were higher than chili sole cropping (1,321 USD ha-1), which pointed to its crucial role in decreasing production risk by reducing yield loss by pests and diseases observed in chili plants. The third part of the study used combined data of stable isotope discrimination and electrical resistivity tomography (ERT) to improve understanding of competition at the crop-soil-hedge interface. Hedges significantly reduced maize grain yield and aboveground biomass in rows close to hedgerows. ERT revealed water depletion was stronger in T1 than in T4 and T6, confirming time domain reflectometry (TDR) and leaf area data. In T4, water depletion was higher in maize rows close to the hedge than rows distant to hedges and maize grain δ13C was significantly less negative in rows close to the hedge ( 10.33‰) compared to distant ones ( 10.64‰). Lack of N increased grain δ13C in T6 ( 9.32‰, p ≤ 0.001). Both methods were negatively correlated with each other (r= 0.66, p ≤ 0.001). Combining ERT with grain δ13C and %N allowed identifying that maize growth close to hedges was limited by N and not by water supply. In conclusion, the results suggested a significant positive interaction between mineral N fertilizer, intercropping systems and soil conservation measures in maintaining or improving crop yields and N balances in Thailand’s hillside agriculture. Simultaneously, combining ERT imaging and 13C isotopic discrimination approaches improved the understanding of spatial-temporal competition patterns at the hedge-soil-crop interface and pointed out that competition in maize-based hedgerow systems was driven by nitrogen rather than water limitation. Therefore, sustainable agriculture might be achieved if farmers in Thailand combine soil conservation measures with appropriate and targeted N fertilizer use.
Land titling policy and soil conservation in the uplands of Northern Vietnam
(2008) Dung, Pham Thi My; Saint-Macary, Camille; Keil, Alwin; Zeller, Manfred; Heidhues, Franz
In Vietnam, a quasi private property regime has been established in 1993 with the issuance of exchangeable and mortgageable long term land use right certificates. Using primary qualitative and quantitative data collected in a mountainous district of Northern Vietnam, this paper investigates the role of the land policy in the adoption of soil conservation technologies by farmers. This issue is of crucial importance in the region where population growth and growing market demands have induced farmers to intensify agricultural production. While poverty has been reduced, environmental problems such as soil erosion, landslides, and declining soil fertility have become more severe over the past years. Among the abundant literature on the impact of property rights and formal land titles in developing countries, only a few studies have focused on the adoption of soil conservation technologies: an important element in sustainable development strategies of fragile agro-ecological areas confronted with increasing population densities. Our findings suggest that soil conservation technologies are perceived as being economically unattractive; therefore, most upland farmers continue to practice the prevailing erosion-prone cultivation system. Focusing on agroforestry as one major soil conservation option, we estimate household and plot level econometric models to empirically assess the determinants of adoption. We find that the possession of a formal land title influences adoption, but that the threat of land re-allocations in villages discourages adoption by creating uncertainty and tenure insecurity. We conclude that more efforts are needed from decision-makers to promote and support the adoption of conservation practices and to clarify objectives of the land policy in order to secure land tenure and foster sustainable development in fragile areas.