长期肥料定位试验栗钙土中磷肥在莜麦上的产量效应及行为研究

研究了高寒半干旱区8年肥料定位试验中,磷肥和有机肥在莜麦上的产量效应、土壤磷素的平衡、土壤Olsen-P及各形态无机磷的变化。结果表明,单施磷肥(N0P1)莜麦增产30.8%、单施氮肥(N1P0)增产109.4%、氮肥和磷肥配合(N1P1)施用莜麦增产314.0%;NP间表现出显著正交互作用,NP(N1和P1)交互作用增产86.9%;施用22.5和45.0.t/hm2有机肥分别比N0P0处理增产115.1%和220.1%;施用有机肥基础上增施磷肥无明显增产效应。不同施肥处理土壤Olsen-P和各形态无机磷的增减取决于土壤磷素的积累与消耗量,7年不施磷肥土壤Olsen-P降低3.3mg/kg。施用磷肥和有机肥土壤各形态磷库均有不同程度的积累;土壤磷素积累以无机磷为主,其中Ca2-P和Ca8-P的积累量分别占土壤无机磷变化总量的19.3%和25.4%,Al-P和Fe-P分别占23.8%和14.8%,O-P和Ca10-P共占13.0%。依据土壤磷素收支平衡状况计算出维持土壤磷素平衡的P2O5用量为45.0.kg/hm2。根据肥料效应函数计算出有机肥用量为0、22.5.t/hm2时,P2O5的最高产量用量分别为98.4.kg/hm2和87.4.kg/hm2。

The yield responses of naked oats to phosphorus fertilizer and phosphorus behavior in chestnut soil in a long-term experiment

The yield responses of naked oats to phosphorus fertilizer and organic fertilizer,the balance between P input and output,and the changes in soil Olsen-P and inorganic phosphorus fraction pool were studied in 8-year experiments on chestnut soil at arid plateau region.The results showed that P fertilization in combination with N fertilizer could help raise naked oats yield,single application of P(N_0P_1) and N(N_1P_0) fertilizers brought about 30.8% and 109.4% of oats yield,respectively.Combined application of N and P fertilizers(N_1 and P_1) gave an increase of 314.0% compared with the control.There was an significant positive interaction effect of N and P fertilizers on yield which resulted in an increase of 86.9% of oats yield.Application of 22.5 t/ha and 45.0 t/ha of organic fertilizer alone gave an increase of 115.1% and 220.1% compared with N_0P_0,respectively,however,applying P fertilizer after the application of organic fertilizer did not show a yield-enhancing effect.The content of soil Olsen-P and inorganic phosphorus fractions were changed by applying P fertilizer and organic fertilizer on different treatments,The content of soil OlsenP decreased by 3.3 mg/kg in no P fertilizer treatment after 7-years cropping.All phosphorus fraction pools addressed with P and organic fertilizers were enhanced at varying degreess.Most of residual P were inorganic phosphorus,among which Ca_2-P and Ca_8P were accounted for 19.2% and 25.3%;Al-P and Fe-P were accounted for 23.4% and 15.3%,respectively;and O-P and Ca_(10)-P were accounted for 13.5% of total inorganic P.According to the balance between P input and output,45.0 (kg/ha) was figured out as the critical rate of P_2O_5 that could maintain the P balance in soil.The recommended application rates of P fertilizer for maximum yield combined with 0 or 22.5 t/ha organic fertilizer using regression equations were 98.4 kg/ha,87.4 kg/ha respectively.