Tentative Research On The Effects Of The Move And Transfer Of Phosphorous And Kalium In Farmland Soil Mixing With Straws

It is well known that China is a leading agricultural nation where billions of tons of straws are produced in agricultural production annually. Nowadays, with China’s social economic growth as well as the increasing farmer’s living standard, energy shortage in rural areas has been resolved, and abundant crop straws are in surplus, thus burning straws has emerged as a social and environmental peril, such as environmental contamination, traffic congestion and the like. Through indoor earth-pillar analog experiment, the author analyses rules of transfer and loss of phosphor and kalium in soil solution from different soil which yearns straws, and simulates the vertical distribution of moisture and phosphorous in earth pillars by adopting both one dimensional simulation of moisture move and transfer and mathematical simulation of solute move and transfer. The major research findings are as follows:(1) Mixing straws in soil undoubtedly decreases the consistency of dissolved phosphorous and phosphor between20cm and40cm from above, whereas it has a comparatively small influence on that of below60cm from surface. As more straws are mixed in soil, the consistency of dissolved phosphorous and phosphor in soil solution at vertical section decreases in small range. The consistency of dissolved phosphorous in straw-earth model300kg/mu,400kg/mu,500kg/mu and600kg/mu on average falls by16.58%,28.76%,38.60%,41.95%respectively compared with that of non-straw-earth model SO. Similarly, the consistency of phosphor in straw-earth model300kg/mu,400kg/mu,500kg/mu and600kg/mu on average decreases by18.68%,31.17%,40.99%,42.75%respectively in comparison to that of non-straw-earth model SO. There are tiny distinctions and variations between straw-earth model500kg/mu and600kg/mu. In full consideration of pollution control and the quantity of straws in farmland,500kg of straws per mu (=0.0667hectares) is a comparatively superior way of straw disposal.(2) Through the comparison of the size of dissolved phosphorous and granule phosphor in soil solution, the ratio of dissolved phosphorous in phosphor at different depths of soil solution is higher than that of granule phosphor in phosphor. As the straw dosage increases, the ratio of dissolved phosphorous in phosphor rises only in a small range. This indicates that dissolved phosphorous is the main factor in the move and transfer of phosphorous in soil during the season of planting paddies. (3) Disposing straw in soil affects the transfer and loss of kalium in a certain degree. The consistency of kalium in straw-earth model300kg/mu,400kg/mu,500kg/mu and600kg/mu on average falls by9.55%,17.71%,24.04%,28.52%respectively, compared with that of non-straw-earth model SO. Unlike phosphorous, kalium in straws exists in ionized state, thus it can be easily removed through watering. In conclusion, the effect of kalium blocked by straws is not as prominent as that of phosphorous blocked by straws.(4) The author firstly builds one dimensional simulation of moisture move and transfer in soil and mathematical simulation of phosphorous move and transfer; then simulates the vertical distribution of the consistency of moisture and phosphorous in earth pillars by adopting combined simulations; lastly makes comparisons between analog values and measured values. Although errors exist between analog values and measured values, currents of change are basically in accordance. Therefore, the combined simulations are applicable in the dynamic prediction of moisture and dissolved phosphorous.May reduce pollution degree of the nutrient outflow to the ground water effectively and be propitious to the construction of agricultural water security of the cieculatory system.