磷肥用量对土壤速效磷及玉米产量和养分吸收的影响

通过两年田间肥料定位试验，研究北疆灰漠土区不同磷肥用量对土壤速效磷含量以及玉米生长和养分吸收的影响。结果表明，不施磷肥或施磷量较低（75 kg/hm²）时，土壤速效磷含量显著降低；施磷量为150 kg/hm²时土壤速效磷含量基本维持平衡；施磷量为300 kg/hm²时土壤速效磷在0～40 cm土壤积累明显。施磷肥可显著增加玉米干物质量，施磷量超过150 kg/hm²干物质量增加不明显。玉米植株的氮素和磷素积累量随施磷量增加而显著增加，磷肥对玉米植株磷素养分的分配影响不大，但可显著促进氮素向子粒的转运，氮素在子粒的分配比例显著增加。施磷肥可显著提高玉米产量，施磷量为150 kg/hm²可维持土壤速效磷平衡并获得高产，是该区玉米的适宜磷肥用量。

Effects of P Rate on Soil Available P, Yield and Nutrient Uptake of Maize

The dynamic of soil available P content under different P fertilizer application rates was investigated in grey desert soil, and the yield and nutrient uptake of maize were also evaluated with a field experiment in 2011 and 2012. The four P application rates were set as 0, 75, 150 and 300 kg/ha, noted as P0, P75, P150, and P300, respectively. The results showed that soil available P contents decreased significantly under P0 and P75 treatments. Soil available P kept balance under P150 treatment, but was extremely accumulated in 0-40 cm soil under P300 treatment. The dry matter weight of maize was increased by P application, but there were no significant differences when P application rate was high(>150 kg/ha). The N and P accumulations of maize plant were increased with P application rate increased. The P application rate had no significantly effects on P distribution proportion in different plant organs of maize, but the N transportation to grain was significantly promoted by P application. N distribution proportions in grain of maize under P300 and P150 treatments were higher than those under P75 and P0 treatments. The yield of maize were also increased by P application. Therefore, the P application rate at 150 kg/ha was the optimum to the soil available P and maize yield.