Change of Phosphate Fraction during Composting of Fresh Waste Leaves of Tobacco

Environmental issue has concerned the public with the build-up of soil phosphorus(P) following application of organic manure.This demands a fully understanding of the change of phosphorus during composting of fresh waste leaves of tobacco and finding out the status of P fertilizer in leaf-made manure.This study had shown that water-soluble and HCl-soluble phosphon were the dominant fractions of P in the compost of fresh waste leaves,in the ranges of 19%-41% and 17%-43%,respectively.However,the former declined progressively upon composting time,but the latter increased,indicating transformation of the more vulnerable water soluble P to the more recalcitrant HCl-extractable P.

Evaluation of tobacco soil fertility suitability of the Sanmenxia area, China, based on geographic information systems

The growth of flue-cured tobacco is sensitive to changes in environmental conditions.Excellent tobacco leaf production is strictly restricted by regional cultivated lands.For the purpose of reasonable utilization and scientific management of Sanmenxia tobacco fields,it is meaningful to evaluate the soil fertility suitability of tobacco crops quantitatively and objectively.In this study,the global positioning system(GPS)technology was used to obtain sample point information automatically.Based on the analysis of fertility properties of soil samples collected from the Sanmenxia tobacco planting regions in Henan Province,we present the index system of soil fertility suitability for tobacco crops.The integrated evaluation of soil fertility suitability was studied with six indices,including organic matter,pH value,available nitrogen(N),available phosphorus(P),available potassium(K),and chlorine(Cl–1)content of surface soil.The subjective grade value was calculated according to S-type and parabola-type functions of the effect of evaluation factors on tobacco crops.Further,the weight value of soil fertility suitability indices was calculated by the method of Hiberarchy analysis.The soil fertility suitability level was evaluated and classified.The suitability map of the Sanmenxia tobacco planting regions in Henan Province was then drawn with the geographic information system(GIS)software mapGIS.It was found that highly suitable fields were mainly distributed in the high mountains in the Southwestern part of the investigated regions where soil pH value and the contents of organic matter were medium,but the contents of available P and available K were higher,accounting for 79.36% of the whole area.Suitable fields were 17% of the whole area,mainly distributed in the middle part of the investigated regions where soil pH value was higher.Unsuitable fields existed in the northern-east and middle part of the Sanmenxia where the contents of soil Cl^(–)was very high,accounting for 3.51%of the whole regions.

Spatial heterogeneity of available zinc, copper, and manganese in Xiangcheng Tobacco Planting Fields, Henan Province, China

Geostatistical methods were used in combina-tion with geographical information system(GIS)technol-ogy to analyze the spatial distribution characteristics of available zinc,copper,and manganese in the Xiangcheng tobacco planting fields,Henan province,China.Analysis of the isotropic variogram indicated that the Zn semivar-iogram was well described with the Gaussian model,with the distance of spatial dependence being 900.7m;while the Mn semivariogram was well described with spherical models,with the distance of spatial dependence being 14060m;and,the Cu semivariogram was well described with exponential models,with the distance of spatial dependence being 27860.7m.Mn and Zn were strongly spatially dependent,with the C_(0)/sill being 0.014 and 0.147 in this given region;while Cu was moderately spatially dependent,with the C_(0)/sill being 0.3528.With the kriging analysis,the spatial distribution maps of contents of these three trace elements in the Xiangcheng tobacco planting regions was drawn with the Arcview software.It was found that the soils with higher content of Mn were mainly distributed in the high mountains of the southern part of the given regions,while the soils with higher content of Cu were mainly distributed in the south,decreasing from the south to the north.The soil with contents of Zn in the range of 0.76–1.33 mg/kg existed in the high mountains of the west and middle parts of the investigated regions,accounting for 76.11%of the whole area.