Population carrying capacity and sustainable agricultural use of land resources in Caoxian County (North China)

In this study, an attempt is made to assess the potential sustainable agricultural use of the land resources in Caoxian County in north China. Based on a land resources inventory (physiography, climate, soil, land use and management), the rotation of winter wheat-summer maize was selected as the major land utilization type of grain production in the study area. Land use requirements were adapted to the local conditions and hierarchical production potentials were estimated using the collected data. Satisfactory results have been achieved for six scenarios combining local management practices and input levels. The population carrying capacity has been obtained and guidelines for a sustainable use of land resources were formulated. Conclusions were drawn with regard to the methodologies applied

Development of a Web-based land evaluation system and its application to population carrying capacity assessment using .Net technology

The multi-disciplinary approach used in this study combines the state-of-the-art IT technology with an elaborated land evaluation methodology and results in a Web-based land evaluation system (WLES). The WLES is designed in such a way that the system operates both as a Web Application and as a Web Service. Implemented on top of the .NET platform, the WLES has a loosely coupled multi-layer structure which seamlessly integrates the domain knowledge of land evaluation and the soil database. The Web Service feature makes the WLES suitable to act as a building block of a larger system such as that of the population carrying capacity (PCC) assessment. As a reference application, a framework is made to assess the PCC on the basis of the production potential calculations which are available through the WLES Web Service interface

The inverse relationship between farm size and productivity in rural Rwanda

The Rwandan government has recently adopted new agricultural and land policies that strive to increase productivity in the agricultural sector though land consolidation and concentration, and through the promotion of regional crop specialisation and monocropping. This paper, however, identifies the strong inverse relationship between farm size and land productivity under the current land management system; also when taking into account farm fragmentation, crop diversification, frequency of multicropping and household size. In addition, it concludes that increased farm fragmentation, higher frequency of multicropping, and more crop diversification do not necessarily have a significant negative impact upon productivity, on the contrary. The paper reflects upon the implications of Rwanda’s agrarian and land policies

Exploring the potential offered by legacy soil databases for ecosystem services mapping of Central African soils

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PyXRD v0.6.7 : a free and open-source program to quantify disordered phyllosilicates using multi-specimen X-ray diffraction profile fitting

This paper presents a free and open-source program called PyXRD (short for Python X-ray diffraction) to improve the quantification of complex, poly-phasic mixed-layer phyllosilicate assemblages. The validity of the program was checked by comparing its output with Sybilla v2.2.2, which shares the same mathematical formalism. The novelty of this program is the ab initio incorporation of the multi-specimen method, making it possible to share phases and (a selection of) their parameters across multiple specimens. PyXRD thus allows for modelling multiple specimens side by side, and this approach speeds up the manual refinement process significantly. To check the hypothesis that this multi-specimen set-up – as it effectively reduces the number of parameters and increases the number of observations – can also improve automatic parameter refinements, we calculated X-ray diffraction patterns for four theoretical mineral assemblages. These patterns were then used as input for one refinement employing the multi-specimen set-up and one employing the single-pattern set-ups. For all of the assemblages, PyXRD was able to reproduce or approximate the input parameters with the multi-specimen approach. Diverging solutions only occurred in single-pattern set-ups, which do not contain enough information to discern all minerals present (e.g. patterns of heated samples). Assuming a correct qualitative interpretation was made and a single pattern exists in which all phases are sufficiently discernible, the obtained results indicate a good quantification can often be obtained with just that pattern. However, these results from theoretical experiments cannot automatically be extrapolated to all real-life experiments. In any case, PyXRD has proven to be useful when X-ray diffraction patterns are modelled for complex mineral assemblages containing mixed-layer phyllosilicates with a multi-specimen approach

Mineralogical and charge properties of volcanic ash soils from west Sumatra, Indonesia

Four volcanic ash soi1 from two toposequences along Mt Marapi and Mt Talaniau, west Sumatra were studied in order to characterize their mineralogical and charge properties. In all the soils, the silt fraction is composed mainly of gibbsite, cristobalite and feldspars, while the clay fraction is composed mainly of cristohalite, feldspars and halloysite. Gibbsite is only present in the clay fraction of the soils from Mt Talamau, while opal-A is only found in the clay of the soil from Mt Marapi. Allophane contents, computed from Si and Al extracted by ammonium oxalate and pynophosphate, are lower in the surface horizons than in the subsoil This is related to higher amounts of organic matter in the topsoil Due to higher rainfall, the soils of Mt Talamau are more weathered than those of Mt Marapi. This is reflected by lower allophane and higher ferrihydrite contents in the soils of Mt Talamau. In all the soils, the surface horizons have lower pH,, value than die under lying B-horizons. The AEC is higher in the subsoil than in the topsoil, having values of 0.3 -1.1 cmol, /kg soil