Lime Fertilization On Soil Types And Rates And Loss Of Contaminant

Severe soil acidification is a major constraint to Phyllostachys praecox sustainable management of Lin’an city, Zhejiang province, so improved acidified soil by liming became the important measures in the process of Phyllostachys praecox production.However, the effect of soil nitrogen and phosphorus transformation and loss by liming is lacking. In this study, soil samples from Phyllostachys praecox of various planting years were selected to simulate and analyze the effect of liming on soil nitrogen availability. An intermittent leaching method was adopted to investigate nitrogen mineralization rates and potentials in bamboo soils with various lime application rates. At the same time, a degradation serious slope Lei bamboo site was selected to investigate the effect of liming on soil nitrogen and phosphorus runoff loses in the Huang Gang village, Taihuyuan town. The obtained main conclusions were listed as follows:1) Under the intensive management with long-term fertilization and continuous mulch for many years of Lei bamboo stands, soil pH decreased greatly, however, soil organic matter and nitrogen content increased obviously with the increasing of bamboo plantation time. Soil nitrogen mineralization process of different liming treatment in119days of Lei bamboo stands could be fitted well using one order reaction kinetics equation. After limed, soil cumulative mineralized nitrogen and nitrogen mineralization potential were significantly higher than that without liming. Soil nitrogen availability was improved with liming greatly. According to the estimation, a suitable amount of liming on bamboo soil is4-8g/kg. Much more lime would lead to an excessive accumulation of soil mineral nitrogen, and result in a high nitrogen loss. Therefore, as for the acidified bamboo stands, we need liming in reasonable, strictly control the use of nitrogen fertilizer, increase soil pH and improve soil nitrogen availability. Consequently, the production of Lei bamboo may be sustainable.2) In Lei bamboo stand, NO3--N content did not increase immediately after liming. When urea applied in March, liming increased the content of NO3--N significantly. The liming effect on soil nitrate diminished with time due to plant absorption and water leaching. On the contrary, the content of NH4+-N increased rapidly in the treatments with or without liming as68.06and60.93mg/kg at the early stage. However, it dropped quickly in January and February and then increased to a peak at March of the year after fertilization. Generally, NH4+-N content of limed soil was lower than the control, the maximum difference was81.84mg/kg. Obviously, liming had a significant effect on soil NH4+-N content. Content of available P in soil was significantly increased in the early stage from November to April, while there was no significant difference with or without liming. In this period, the content of available P was stable as300mg/kg. Since May, the content of available P with or without liming showed significant differences. It was much lower with liming than that without liming. Totally, the liming decreased the content of available P in Lei bamboo soils.3) The limed soil loss of NO3--N, NH4+-N, dissolved nitrogen were719.1g/hm2,88.58g/hm2and1058.6g/hm2, respectively, reduced by148.1g/hm2,43.02g/hm2and180.8g/hm2compared to the control. The liming decreased NO3--N loss and weakened the peak concentration of NO3--N in loss. After November, the loss rate of NH4+-N decreased, but it was much obvious in the limed treatment. During the experiment, phosphate loss from the liming treatment was lower than that without liming except for August. The results indicated that liming measure could lead to a low nitrogen and phosphorus loss, but the effect decreased with the time.