| Soil is the most valuable natural resouces for the human surival and sustainable development of agriculture. Currently, cultivated land in China is very limited, but the quality of cultivated land is generally poor. Therefore, we not only need to protect the amount of cultivated land, but also be focus on how to improve soil productivity. But only take seriously about improving soil fertility and rational fertilization can we improve soil productivity to achieve the sustainable use of soil resources.Soil is a continuum of spatial and temporal variability regardless of the scale size, spatial variation of soil features is universal. But the fertilization management in traditional agricultural production was homogenization, it very easily led to the imbalance of soil nutrients supply, low utilization rate of fertilizer and the pollution of the water environment. Depth study on the spatial variability of soil nutrients, then determine the reasonable soil nutrients management unit, it is the foundation to achieve the management of soil nutrients and rational fertilization. The town of Donghuayuan and Shacheng were selected as the study areas in Huailai, Hebei Province. The contents of available nutrients were evaluated, the spatial variability and spatial distribution of soil nutrients were analysised by using GPS, GIS with geostatistics. And field experiments were conducted to understand the effects of biochar application on the soil fertility and wine grape growth in the nursery in Donghuayuan. The application rate of biochar was20t/hm. The results of the research are summarized as follows:(1) The contents of soil nutrientsIn Donghuayuan areas, the contents of soil organic matter, nitrate nitrogen and available K were low; that of available P and S were moderate; the available Mg, Na and microelements is very low; the contents of exchangeable calcium were extremely high. In shacheng areas, soil organic matter, available K, Mg and Na were low; NO3--N and available P were moderate; the content of SO4-S was high; the contents of exchangeable calcium were extremely high; the contents of avaiable copper and boron were at a moderate and low level, respectively; that of iron, manganese and zinc were very lack.(2) Spatial variability of soil nutrients The descriptive statistical analysis and normal distribution test showed that:The variable coefficient of the soil nutrients in Donghuayuan areas were between17.8%to76.2%which were belong to the moderate spatial variation; the large and middle elements of soil followed a normal distribution or a lognormal distribution. In Shacheng areas, the coefficient of variation was7.1%-84.8%, and that of exchangeable calcium(7.1%) is a weak variation, other elements were moderate spatial variation; soil nutrients obeyed normal or log-normal distribution except for Zn. The semivariograms and models showed that soil organic matter, available phosphorus and potassium were best fitted in Gaussian, Gaussian and spherical model respectively, and they all had a strong spatial correlation in Donghuayuan areas. In Shacheng areas, available sulfur was described by the linear model, and other elements were best fitted by spherical, Gaussian and exponential model. The nugget/sill were less than25%for soil nutrients, but except for that of available iron. This means that the spatial variability of available iron was mainly produced by random factor, while that of other elements was primarily caused by structural factors.(3) The management recommodations and spatial distribution of soil nurtrientsGeostatistics combined with GIS was applied to analyze the spatial distribution of nutrients. According to the maps of soil nutrient distribution drawn by GIS, we divided soil organic matter, available phosphorus into2and3as partition management unit in Donghuayuan. For Shacheng, soil organic matter and nitrate nitrogen, available phosphorus, magnesium, boron and copper could be divided into2,2,3,2,2and2as nutrient partition management uint, respectively.(4) Effect of biochar application on soil propertiesBiochar application to the soil of the nursery could reduce soil bulk density, increase soil organic matter and the valid nutrient contents. Compared to the control, the contents of the soil organic matter, alkali-hydrolyzable nitrogen, available phosphorus, available potassium increased by68.4%,30.2%,192.1%,82.5%and60.5%, respectively.(5) Effect of biochar application on grape seedling growthBiochar application significantly promoted plant growth. The fresh weights and heights of grape plants, stem diameters, chlorophyll contents, the number of coarse roots (D>2.00mm) and fine roots (D<1.38mm) increased by21.2%,13.9%,10.1%,8.9%,28.4%and61.0%, respectively. Therefore, Biochar had significant potential as soil conditioner for the grape growth. |
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