The Study Of Temporal And Spatial Variation Of Soil Nutrient And Winter Wheat Growth Information On Field Scale

In this paper, the temporal and spatial variation of soil nutrient and crop growth information were studiedas the objective and two studies were carried out as follows:(1) Explored the temporal and spatial variation rules of soil nutrients (phosphorus, potassium, organic matter, total nitrogen and available nitrogen) in winter wheat-summer maize rotation field from2000to2007.(2) Using hyperspectral technology, exploredthe temporal and spatial variation of winter wheat growth information in jointing stage、heading stage、early and middle filling stages,and discussing Soil characteristics data the causes of spatial variation of yield、grain protein and winter wheat population growth combining with the soil characteristics data. The research results were as follows:1. Results show that, a) potassium and phosphorus nutrients reduced gradually in study area from2000to2007; the soil total nitrogen content was high in some area, but it also had the downward trend; Organic matter content slightly increased within a state of equilibrium. b)The CV of all soil nutrientswere ranged from11.00%to51.71%, which belonged to medium degree of variation. As time goes on, the spatial distribution law of effective phosphorus, organic matter, total nitrogen, alkali solution nitrogen soil available phosphorus (AP), alkali-hydrolyzable nitrogen (AN), total nitrogen (TN) and organic matter (OM) were the same. Although the spatial distribution law of available potassium (AK) in2001was different from that in2000and2007, the spatial distribution of AKin2000and2007was similar. This showed that the spatial distribution of soil nutrients has certain stability. c)When the soil physical characteristics had big change, spatial distribution characteristics of soil nutrients will be affected significantly; but when field cultivation management was relatively consistent over long period of time, structural factors (especially soil characteristics and climate) will play the leading role.Therefore, based on the stability of the spatial distribution of soil nutrients in time, in the absence of large-scale soil preparation, soil nutrient field investigation period could be appropriately prolonged. Because of the big demand of phosphate and potassium fertilizer in Winter wheat and summer corn field, the input of phosphorus and potassium fertilizer should be increased, nitrogen fertilizer should be increased in parts of zones.2.Through the study of temporal and spatial variation of winter wheat growth information, the results show that:a) The optimal vegetation indexes to represent winter wheat growth spatial variability at jointing stage, heading stage, grain filling stage and milk stage are GNDVI, Vari-700, MSAVI, Vari-700; the optimalparameters to crop nutrients are NBI_G, NBI_G, NRI and NRI. b) The spatial distribution of winter wheat growth and nutrient in different period are different, but overall, there is a small difference between North and South, large differences between East and West; well in East but worse in West. In the whole growth period, the change trends of winter wheat growth and nutrient dynamics aremainly divided into three kinds:winter wheat in the region with high growth and nutrient in the early stagesgrow well in late stages; winter wheat in the region with poor growth or nutrient regions in the early stage, due to fertilizer and water management, will gradually changed better later; the growth andnutrient of winter wheat are instability in different period. c) The spatialdistribution of winter wheat yield appears obviously regional. Under the circumstance that there is a good growth conditionof winter wheat, high nutrients of soil in the whole growth period, high soil nitrate nitrogenand moderate altitude, the yield of winter wheat is high. When the area has high soil nitrate nitrogen content and instable growth condition of winter wheat or nutrients of soil, the yield of winter wheat is low. The yield of winter wheat is low in the area with low nitrate nitrogen content. If the study area terrain is too high or too low, winter wheat yield is ususlly low. Therefore, the winter wheat field preparationbefore sowing and management is particularly important.d) Thespatial distribution of winter wheat grain protein appears obviously regional. The spatial distribution of winter wheat grain protein content have obviously corresponding relationship with the spatial distribution of nitrate nitrogen content in soil and crop nutrient at the jointing stage, heading stage and milking stage. Winter wheat nutrient spatial distribution at filling stage is less guide significance to grain protein. The effect of topography on crop grain protein is mainly reflected in the influence of topography on soil fertilizer and water.