Spatio-temporal Variability Analysis Of Nitrogen, Phosphorus And Potassium And Nutrient Leaching Characteristics In Huantai Country

In order to realize precision fertilization and prevent soil fertility degradation, geographicinformation system (GIS) and geostatistics were combioned to investigate the spacedistribution of alkali-hydrolyzable nitrogen, rapidly-available phosphorus and potassium in1989and2006in high yield production area of Huantai County in Shandong province, northChina. Field observation location suggested the nitrogen loss, the eco-environmental effect,the soil water and netrogen behaviors under three different planting systems. The main resultsare as follows:(1) Spatio-temporal Variability of Soil Nutrient: The results suggested that the contentsof alkali-hydrolyzable nitrogen in soil were generally increased compared with that in1989,the area over the middle level (>91mg·kg-1) occupied21.23%percent of the whole researcharea, the area with alkali-hydrolyzable nitrogen contents between61mg·kg-1and90mg·kg-1increased by7.05%, while the area with low content (<60mg·kg-1) decreased by8.07%. Thecontents of rapidly-available phosphorus were also significantly increased, which was mainlyresulted from transformation from lower to higher level. This conversion had two traits asfollows: the area of rapidly-available phosphorus in high concentration (>21mg·kg-1)increased by26.92%, and that in low concentrations was decreased by52.75%. Additionally,the contents of rapidly-available potassium in soil had been general improved and the averagecontents were118mg·kg-1in2006. Especially the contents of rapidly-available potassium(101mg·kg-1and150mg·kg-1) increased by25.18%. The soil nutrient contents were allincreased significantly. In conclusion, the present study provided guidance on makingdecision of high efficiency fertilizer utilization and might be beneficial for sustainingagricultural development in Huantai County. (2) Nitrate leaching characteristics in different planting systems farming soils: Bothwheat-corn and chives rotations were exibited soil water leakage due to the supplyment of soilwater were higher than their consumption. The order of the nitrate nitrogen content in0-200cm soil profile was as chives lands> wheat-corn lands> woods lands, which may beascribed to the higher demond of fertilizer and water in chives. The strong rainfall and heavyfertilizer resulted in generally higher nitrate nitrogen content in chives as well as the lowerpeak value in nitrate nitrogen. Therefore, traditional irrigation systems may lead to a greatleakage in vegetable lands. Due to the short water supply in fast-growing forestry, waterpotential at2meter soil exibited a decreaseing tendency. Besides, the less supplyment offertilizer, the more stable of nitrate nitrogen content in deep soil profile. The nitrate nitrogencontent in woods showed relative stable levels in the2010winter-wheat season. The strongrianful during June to August in2011caused water saturation in soil, leading to the infiltrationat high nitrogen content of soil solution, and eventually increased the nitrate nitrogen contentin chives and wheat-corn lands. By contrast, the changes in woods were more stable. It mayresult from the lower fertilizer and slight drought stress for a long time. Therefore, transientrainful was not enough caused the leakage of soil water and nitrate nitrogen leach.