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针对磷肥施用量大且利用率不高的问题,通过2011—2013年在甘肃省农业科学院张掖绿洲灌区农业生态环境重点野外台站进行定位试验,研究了不同施磷量对露地大白菜产量、磷肥利用率以及磷素平衡的影响。结果表明:大白菜产量随施磷量的增加先增加后呈下降的趋势。在施磷量为112.52 kg·hm~(-2)时产量达到最高,且显著高于其他处理,与不施磷处理相比,增产13.3%～23.8%,此时磷肥利用率为14.2%。土壤中Olsen-P和CaCl_2-P呈现较好的正相关性,土壤Olsen-P含量为24.22 mg·kg~(-1)时对应的施磷量为111.1kg·hm~(-2),表明当土壤中Olsen-P含量小于24.22 mg·kg~(-1)时,土壤中的磷素不发生盈余,对环境不造成污染。当施磷量为60.17 kg·hm~(-2)时,磷输入与输出达到平衡,即此施磷量水平能满足作物的需求。结合研究区的土壤肥力状况,综合产量、磷肥利用率及土壤有效磷含量,干旱绿洲灌区磷肥投入阈值在60.17～112.52kg·hm~(-2)时,能保证露地大白菜高产,并且不会造成环境污染。
Aiming at the problem of large amount of phosphate fertilizer and low utilization rate, through the positioning experiment at key agricultural agro-ecological environment stations in Zhangye Oasis Irrigation Area of Gansu Academy of Agricultural Sciences in 2011-2013, the effects of different phosphorus application rates on the yield of Chinese cabbage in open field, Utilization and the impact of phosphorus balance. The results showed that the yield of Chinese cabbage increased first and then decreased with the increase of phosphorus application. The yield reached the highest when the phosphorus application was 112.52 kg · hm -2, and was significantly higher than other treatments. Compared with no phosphorus treatment, the yield increased by 13.3% -23.8%, and the utilization rate of phosphorus was 14.2%. The positive correlation between Olsen-P and CaCl 2 -P in soils was observed. The corresponding phosphorus application rate was 111.1 kg · hm -2 when Olsen-P content was 24.22 mg · kg -1 When the content of Olsen-P in the soil is less than 24.22 mg · kg -1, the phosphorus in the soil does not generate any surplus and does not cause any pollution to the environment. When phosphorus was 60.17 kg · hm -2, phosphorus input and output reached a balance, that is, the level of phosphorus application could meet the demand of crops. According to the status of soil fertility, comprehensive yield, P utilization and available P content in the study area, the threshold of P input in the irrigated oasis irrigation area was 60.17 ~ 112.52 kg · hm -2, which could ensure the high yield of Chinese cabbage in open field Cause environmental pollution.