有机、无机磷肥配施对宁夏引黄灌区露地蔬菜磷素吸收利用与磷平衡的影响

2011—2013年,在宁夏引黄灌区利用田间定位试验研究了不同有机、无机磷肥配施对露地蔬菜的产量、磷素吸收利用、土壤无机磷残留和磷平衡的影响,并提出了合理的磷肥投入阈值。结果表明,过量增施磷肥对露地蔬菜的增产作用不显著。露地蔬菜经济产量与施磷量都符合二次曲线关系,花椰菜、紫甘蓝和大白菜最大产量施磷量分别为P2O5332.3、304.5、377.8 kg/hm2,最佳经济施磷量分别为P2O5282.9、271.2、365.3 kg/hm2。增施磷肥能促进露地蔬菜地上部磷素吸收累积,磷肥利用率随化学磷肥用量增加而降低。随着施磷水平的提高,0~20 cm土壤Olsen-P和Ca Cl2-P含量都呈增加趋势。土壤磷平衡与施磷量呈线性正相关关系,化肥磷施用量越高土壤磷素盈余越大。2011—2013年花椰菜、紫甘蓝和大白菜季合理的磷肥投入阈值范围分别为141.0,332.3]、107.1,304.5]和104.9,377.8],施磷量、蔬菜产量及地上部吸磷量是影响该阈值范围的主要因素。

Effect of Different Combined Application of Organic-inorganic Fertilizers on P Uptake and Utilization of Open Field Vegetables and P Balance in Yellow River Irrigation Area of Ningxia

A location field experiment was conducted in the Yellow River Irrigation Area of Ningxia During 2011 to 2013 to study the effects of different combined application of the organic-inorganic fertilizers an the yields, P uptake and utilization, soil inorganic P residue and P balance, of the open field vegetable and a suitable P input threshold was put forward. The results indicated that there was no significant yield increment for open field vegetables after over use P fertilizers. The relationship between the economic yield of the open field vegetables and total P application rates could be described by quadratic equation, the maximal P input for open field broccoli, purple cabbage, and Chinese cabbage was P2O5 332.3, 304.5, and 377.8 kg/hm2, and the corresponding optimal P input was P2O5 282.9, 271.2, and 365.3 kg/hm2, respectively. The application of organic-inorganic P fertilizers could increase shoot P uptake of the open field vegetables, and P use efficiency was decreased with the increasing of chemical P application rates. With the increasing of organic-inorganic P fertilizers application rates, both Olsen-P and CaCl2-P content in the topsoil of 0-20 cm were increased, and the significant linear correlation was found between Olsen-P and CaCl2-P （R2=0.743）. The soil P surplus was higher with the increasing of chemical P fertilizers application rates. The suitable P input thresholds of open field broccoli, purple cabbage, and Chinese cabbage during 2011 to 2013 were ranged 141.0, 332.3], 107.1, 304.5] and 104.9, 377.8], respectively, and P application rates, yield and shoot P uptake of vegetables were the main factors affecting the P input thresholds.