Distribution Of Phosphorus In Solid And Liquid Phase And Influential Factors Of Microbial Biomass C/P Ratio In Agricultural Field

Phosphorus is an essential element for plant growth and plays an important role in the agricultural production. The amount of manufactured and imported phosphate was increased in the last years and the phosphate resource condition was serious shortage in China. Phosphate fixation in soil can directly lead the fertilizer utilization lower and accumulated in soil. The accumulation of phosphate has two effects, one is the waste of the phosphate resource, and the other is water eutrophication by farmland drainage, surface runoff, underground runoff and leakage. This nonpoint water pollution of phosphate made the eco-environmental problems more serious than before. For the sustainable development of agriculture, enhance the phosphate utilization and reduce nonpoint pollution have significant affect on agricultural production and eco-environment.This research was based on the aim of increase the phosphate utilization, decrease nonpoint pollution and sustainable agriculture development for the food, ecology, environment security. Four typical long term agricultural experiment station, which separately represent four farmland ecosystems, the median and lower reaches of the Yangtze River, the Huang-huai-hai region, the Northeast region and the Loess Plateau were selected in this experiment. We also test soil samples from the First Agricultural Research Station of the Northwest agriculture and Forest University, and the long term experimental station in Rothamsted Research, United Kingdom. We tested the phosphorus distribution between solid and liquid phase, fixation, soil microbial biomass and other relative index. We want to establishment a theory to instruct the use of phosphate in different hydrothermal and fertilizer environmental condition in agriculture field. We want to get some useful scientific theory to the food, ecology and environment security. Our research result showed as below: (1) Distribution coefficient of phosphorus in the solid and liquid Phase is a important quantitative index to describe phosphorus in soil solution and soil particle surface. The distribution was affected by soil moisture, soil thermal, soil solute concentration, time-series, and soil texture.In this simulated study, thought laboratory incubation experiment and setting up the different treatments condition such as soil water, soil thermal, soil nutrient and time-series, the distribution of phosphorus in the solid and liquid phase (Kd) and its influential factors in five typical Chinese soils including Red soil, Black soil, Fluvo-aquic soil, Lou soil and Heilu soil were studied using the ultracentrifugation method. The results showed that the Kd-value of different designs are widely divergent to different textural soils, the features of general trend is Red soil > Heilu soil > Lou soil > Black soil > Fluvo-aquic soil. In the different incubation conditions , the phosphorus Kd were increased with the culture time, however, the bioavailability of soil phosphorus gradually decrease. Along with increasing soil water suction and their concentrations,Kd-value changes had an decrease tendency, the Kd decreased with increasing them. In the whole soil thermal gradient,the Kd was minimum with relative increasing liquid volume content at temperatures about 20-25℃, and enhancing the nutrient availability.(2) The suitable and scientific land management practice such as fertilizers cooperating application and organic fertilizer application could enhance the phosphorus utilization efficiency, to decrease the non-point source pollution in the sustainable and stable of ecological agriculture.This experiment tested 9 nitrogen-phosphorus, 8 nitrogen-phosphorus-organic fertilizer ratios in a 25 years long-term wheat experiment field in Changwu research station. The result indicated that the distribution coefficient of phosphorus in solid and liquid phase has correlation with Ca2-P and Active organic phosphorus. Despite the distribution coefficient appeared reverse trend, the total P, P in solid phase and P in liquid phase all were increased with the P fertilizer application when under the same nitrogen fertilizer level. The nitrogen fertilizer applications can affect the phosphorus usage. The total P was the minimum, the P in liquid phase was the maximum and the available P in solid phase has a decrease trend at N135 when P fertilizer at the same level. The distribution coefficient was the maximum at only applying P fertilizer (No nitrogen). The organic matter can trigger the effectiveness of nutrient. Balanced fertilization has magnitude affect on nutrient efficient utilization.(3)The huge specific surface area and surface active group are two typical properties of humic acid. These two characters made the humic acid have great function in the soil phosphorus movement and can activate the phosphorus by the strong adsorption ability. We used the shock equilibrium method to research how the humic acid affects phosphorus adsorption by change the concentration of humic acid in five typical soils of China. Freundlich, Langumuir and Temkin models were used to quantify the influence degree of humic acid on phosphorus adsorption. The result showed that these three models, Freundlich, Langumuir and Temkin model could simulate the phosphorus adsorption and the Freundlich was the best model to describe it. When stimulate different soil, Freundlich was more suitable to Black soil and Red soil, then is the Lou soil and Heilu soil, the alluvial soil was the last. Humic acid can activation the soil phosphorus for the adsorption capacity and adsorption rate was all decreased when add humic acid to soil. The maximum adsorption capacity was changed 50 % to 60 % in Lou soil and Heilu soil, alluvial soil was the follow, the Black soil and the Red soil were the least.(4) Soil microbial biomass C/P is one of the most important soil quality indexes, which has correlation with the soil pH, total soil carbon, inorganic phosphorus and phosphorus recovery. Soil pH can affect the soil nutrient transformation and other soil properties. This experiment researched the soil microbial carbon phosphorus ratio and phosphorus availability in different soil pH condition by tested the soil chemical and biochemical properties in Rothamsted research station, United Kingdom. We also compared the result of bray method and Olsen method to test soil microbial phosphorus in acid soil. The result showed that soil microbial carbon phosphorus ratio can be used as a useful index to soil phosphorus availability. In general, soil microbial carbon phosphorus ratio has correlation with soil pH, total carbon, inorganic phosphorus and phosphorus recovery. Soil pH affects soil chemical and soil biochemical properties. Phosphorus recovery and soil microbial carbon phosphorus ratio increased with soil pH. However, soil total carbon, total phosphorus, soil carbon phosphorus ratio and soil microbial phosphorus has the reverse trend. Soil respiration linear increased with the incubation time. Soil microbial carbon has a significant positive correlation with ATP (r=0.912, n=16). Bray-1 method was more suitable in acid soil condition for it has a small stand error, despite the result of Olsen and bray-1 method has a good correlation. Soil pH had some effect on the transformation process from soil microbial phosphorus to inorganic phosphorus.(5) Soil microbial biomass phosphorus, an important nutrient for the plant phosphorus, can influence the soil P supplying and regulation. It can be affected by many environmental factors.An indoor incubation experiment were conducted to detect the law of soil microbial biomass phosphorus, soil microbial biomass carbon phosphorus ratio and phosphorus effectiveness by add high, median, low concentration of inorganic phosphorus and ryegrass matrix carbon in a poor nutrient and carbon agricultural field. The research showed that the additional inorganic phosphorus has limited effect on the soil microbial biomass carbon. However, the additional ryegrass matrix carbon could significant affect the soil microbial biomass carbon. That means the carbon amount has great effect on the soil microbial biomass carbon dynamics. The additional phosphorus has slight effect on soil microbial biomass phosphorus in low carbon condition; nevertheless, additional carbon can importantly affect it. This was apparent when the high carbon ryegrass matrix was added to the soil. The turnover cycle of soil microbial biomass phosphorus was short and the fluctuation of soil microbial carbon phosphorus ratio was higher. The soil microbial biomass carbon phosphorus ratio has two higher peaks, respectively, 5 and 25 days after the additional matter was added. The lower peak after 10 days means the activity of soil microbe was higher and content more phosphorus. The phosphorus utilization was more active. There has a correlation between available phosphorus with soil microbial biomass phosphorus, microbial biomass carbon phosphorus ratio and can simulate to logarithmic function and binomial function.