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Kraus, D., Weller, S., Klatt, S., Haas, E., Wassmann, R., Kiese, R., et al. (2015). A new LandscapeDNDC biogeochemical module to predict CH4 and N2O emissions from lowland rice and upland cropping systems. Plant Soil, 386(1-2), 125–149.
Abstract: Replacing paddy rice by upland systems such as maize cultivation is an on-going trend in SE Asia caused by increasing water scarcity and higher demand for meat. How such land management changes will feedback on soil C and N cycles and soil greenhouse gas emissions is not well understood at present. A new LandscapeDNDC biogeochemical module was developed that allows the effect of land management changes on soil C and N cycle to be simulated. The new module is applied in combination with further modules simulating microclimate and crop growth and evaluated against observations from field experiments. The model simulations agree well with observed dynamics of CH (4) emissions in paddy rice depending on changes in climatic conditions and agricultural management. Magnitude and peak emission periods of N (2) O from maize cultivation are simulated correctly, though there are still deficits in reproducing day-to-day dynamics. These shortcomings are most likely related to simulated soil hydrology and may only be resolved if LandscapeDNDC is coupled to more complex hydrological models. LandscapeDNDC allows for simulation of changing land management practices in SE Asia. The possibility to couple LandscapeDNDC to more complex hydrological models is a feature needed to better understand related effects on soil-atmosphere-hydrosphere interactions.
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Abdelrahman, H., Cocozza, C., Olk, D. C., Ventrella, D., & Miano, T. (2017). Carbohydrates and Amino Compounds as Short-Term Indicators of Soil Management: Soil. Clean Soil Air Water, 45(1), 757.
Abstract: The objective of this work was to evaluate the suitability of carbohydrates and amino compounds in soil and soil organic matter (SOM) fractions to depict the management-induced changes in soil over short-term course. Soil samples were collected from two experimental fields managed according to organic farming regulations and a sequential fractionation procedure was applied to separate the light fraction (LF), particulate organic matter (POM), and mobile humic acid (MHA). Contents of carbohydrates and amino compounds were determined in soil and correspondent SOM fractions. Over a 2-year course, carbohydrate contents decreased in the LF fraction while it increased noticeably in the POM and slightly in the MHA fractions leading into questioning whether decomposing materials get incorporated into older fractions. Amino N content constituted up to 30% of total soil N, with a major contribution of the humic fraction (MHA). Although the LF, POM, and MHA fractions showed the greatest amino N content after the compost-legumes combinations, the carbohydrate and amino N contents in the POM and MHA fractions of the unamended soil increased as large as the corresponding fertilized plots, underlining that conservative soil management results in accumulation of labile forms of soil C and N that consequently might build up soil fertility. The changes after different treatments suggest the suitability of carbohydrates and amino compounds as short-term indicators for soil management.
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