Effects Of Manure Application On Soil Phosphorus Components And Phosphorus Losses Of Farmland

In recent years, with the rapid development of the breeding industry in China, the amount of animal manure phosphorus has increased to 10 million tons, which was equivalent to 90 % of the total input of chemical phosphorus in the same year. This has caused rapid growth of manure phosphorus applying to farmland in some agricultural regions. The investigation from more than 100 towns in intensive agricultural areas showed that: at present, the amount of manure phosphorus applied to farmland has increased to 114 kg P₂O₅/haon average, and higher than 600 kg P₂O₅/hain some special towns, while it was just about 20 kg P₂O₅/hain the early 1980s.The pre-existing researches showed when the number of phosphate fertilizer in the cropland was overdressing; the phosphate fertilizer could wash away on condition that rainfall leads to run off and leaching. The new researches showed that the main components of phosphorus in manure were water soluble phosphorus and free soluble phosphorus, and using manure excessively could lead the phosphorus in cropland to run off. to realize how the amount of manure influence the kinds of phosphorus contents, and expound the changes of soil phosphorus from manure on the effects of wastage of cropland phosphorus, the author designed the field experiments and manual simulation rainfall in situ experiments in LangFang experiment station of CAAS(116°35′37″E , 39°36′04″N ). The manure experiment began between 2008 and 2009, which grew spring maize - winter wheat– summer maize with manure which contained phosphorus 4.49 g/kg, among the amount of phosphorus, water soluble total phosphorus, water soluble inorganic phosphorus, water soluble organic phosphorus and the phosphorus of Olsen extraction agent extracting was 19.9%, 18.4%, 1.5%, 66.1%, separately, and there were three standards in the amount of phosphorus: 0(contrast), 75, 225 kg P/ha, and every standard repeated four to six. The manure used disputably before maize seeding and ploughing after surface application. The simulation rainfall in situ experiments began in the first ten-day period of August, 2009, the experiment designed two rainfall intensity of 120mm/h and 60mm/h, and imitated the processes of the surface runoff from heavy rain and leakage from sustained rainfall, and both the rainfall were 120mm.The results showed that with the increase of manure use level, all the contents of soil total phosphorus, water soluble total phosphorus, water soluble inorganic phosphorus, water soluble organic phosphorus, the phosphorus of Olsen extraction agent extracting in 0-5cm and 5-20cm enhanced observably. Regarding different morphology soil phosphorus, the phosphorus use level in manure on effect of the content of high water soluble soil phosphorus was greater than the content low water soluble soil phosphorus. When the use level of manure phosphorus is 75 kg P/ha, water soluble inorganic phosphorus, soil water soluble total phosphorus, water soluble organic phosphorus, Olsen-P in 0-5cm soil horizon is greater than contrast, and separately1320.6 %, 1044.2 %, 631.3 %, 479.4 %, among them, soil water soluble inorganic phosphorus increases from 0.65 mg P/kg in contrast to 9.24 mg P/kg, while soil total phosphorus only increases 19.0 %, from 636.3 mg P/kg in contrast to 757.5 mg P/kg. When the use level of manure phosphorus is 225 kg P/ha, water soluble inorganic phosphorus, soil water soluble total phosphorus, water soluble organic phosphorus, Olsen-P in 0-5cm soil horizon is greater than contrast, and separately 3755.2 %, 2536.1 %, 715.7 %, 1603.1 %, among them, soil water soluble inorganic phosphorus increases to 25.08 mg P/kg, while soil total phosphorus increases to 1069.8 mg P/kg, only increases 68.1 %.In respect of two type soil horizon, the use level of manure phosphorus effect on surface horizon is greater observably than subsurface horizon. When the use level of manure phosphorus is 75 kg P/ha, all kinds of morphology phosphorus in 0-5cm increase 698.9 % on average than the contrast, while only 154.7 % on average in 5-20cm; the content of soil water soluble total phosphorus in 0-5cm increases from 1.09 mg P/kg in contrast to 12.43 mg P/kg, the content of soil total phosphorus increases from 636.3 mg P/kg in contrast to 757.5 mg P/kg. When the use level of manure phosphorus is 225 kg P/ha, all kinds of morphology phosphorus in 0-5 cm increase 1735.6 % on average than the contrast, while only 634.2 % on average in 5-20 cm; the content of soil water soluble total phosphorus in 0-5cm increases from 1.09 mg P/kg in contrast to 28.63 mg P/kg, the content of soil total phosphorus increases from 636.3 mg P/kg in contrast to 1069.8 mg P/kg.The result of manual simulation rainfall in situ experiments showed that on the condition of the content of soil phosphorus, especially the content of high water soluble soil phosphorus increases with the increased manure, all of the content of the total phosphorus of leakage and runoff, water soluble total phosphorus, water soluble inorganic phosphorus and particulate phosphorus increase observably, among them, the content of water soluble inorganic phosphorus is greatest. When the use level of manure phosphorus is 75 kg P/ha, the content of the total phosphorus of leakage and runoff, water soluble total phosphorus, water soluble inorganic phosphorus and particulate phosphorus is 8.12 mg P/L, 3.48 mg P/L, 3.21 mg P/L, 0.28 mg P/L, 4.64 mg P/L, separately, and increase 588.9 %,3126.6 %,5529.5 %,446.4 %,333.0 % ,than the contrast (1.18 mg P/L, 0.11 mg P/L, 0.06 mg P/L, 0.05 mg P/L, 1.07 mg P/L). When the use level of manure phosphorus is 225 kg P/ha, the content of the total phosphorus of leakage and runoff, water soluble total phosphorus, water soluble inorganic phosphorus and particulate phosphorus from one imitation rainfall is 3.57 kg P/ha, 1.59 kg P/ha, 1.46 kg P/ha, 0.12 kg P/ha, 1.98 kg P/ha separately, and increase 414.7 %, 2398.3 %, 4268.4 %, 312.2 %, 214.6 % than the contrast (0.69 kg P/ha, 0.06 kg P/ha, 0.03 kg P/ha, 0.03 kg P/ha, 0.63 kg P/ha).With the increase of the use level of manure phosphorus and the content of high water soil phosphorus in soil surface horizon, only the content of the total phosphorus in runoff liquid increase observably. When the use level of manure phosphorus is 225 kg P/ha, the content of the total phosphorus in runoff liquid increase from 0.79 mg P/L in contrast to 1.64 mg P/L, increase by 107.1 %, the content of the total phosphorus in runoff liquid increase from 0.58 kg P/ha to 1.15kg P/ha, increase by 98.0 %, and lower observably than runoff. The variation of the content of the water soluble total phosphorus, water soluble inorganic phosphorus, water soluble organic phosphorus, particulate phosphorus is greater, while on the condition of different use level of manure and the content of soil phosphorus, the variation is not observably.In conclusion, when using livestock manure with high water soluble phosphorus and free soluble phosphorus, the content of water soluble phosphorus in soil surface horizon will increase by a wide margin, increase by 10-49 times, the more using manure, the greater it effects on the content of water soluble phosphorus in soil surface horizon. While with the enhancing of the content of water soluble phosphorus in soil surface horizon, on the condition of continue rainfall, the leakage wastage of water soluble phosphorus in field will increase by a wide margin, which will increase from 0.06 kg P/ha to 1.59 kg P/ha in one imitation rainfall, and increase by 25.0 times. Therefore, at the same time of using fully phosphorus nutrient resource from livestock and reducing livestock pollution, we notice to use livestock manure scientific and control effectively the runoff of phosphorus in field arise from manure.