黄土区长期施用磷肥对冬小麦产量、吸氮特性及土壤肥力的影响

为了明确长期施用磷肥对冬小麦产量、吸氮特性和土壤肥力的影响,通过21年的黄土高原旱地长期定位肥料试验,测定了冬小麦每株有效小穗数、穗粒数、成穗数、千粒重和干物质量以及植株和土壤中的氮、磷养分含量。结果表明,合理施用磷肥(45～135 kg/hm2)能提高冬小麦穗粒数和千粒重,并能显著提高每株有效小穗数、成穗数和冬小麦抽穗期后干物质累积量,继而显著提高产量,其中当磷肥施用量为135 kg/hm2时,产量最高,为2 869.0kg/hm2,但磷肥施用量过大(达到180 kg/hm2)时,成穗数和抽穗期后干物质累积量显著降低,导致产量显著下降;冬小麦的氮素累积动态呈先增加后下降的趋势,增施磷肥能增加冬小麦吸氮量,但到成熟时,冬小麦地上部分出现氮素损失,损失量达13.4%～44.2%;长期施用磷肥能增加土壤有机质和氮素含量,并显著提高土壤磷素含量,其中全磷含量增加10.7%～64.5%,速效磷含量增加234.6%～667.3%。长期合理施用磷肥,能提高冬小麦产量、吸氮量以及土壤中有机质和氮磷养分含量。

Effects of long-term application of P fertilizer on the yield of winter wheat and characteristic of N absorption and soil fertility in dry-land of Loess Plateau

An experiment of 21-year-long-term application of P fertilizer was carried out to study the effects on the yield of winter wheat,characteristic of N absorption and soil fertility in dry-land Loess Plateau.The avail spikelets per spike,grains per spike,spike no.per hm2,1 000 grains yield and the dry matter accumulation of winter wheat were measured,as did the total N,P in both plants and soil.The results showed that the grains per spike and 1 000 grains yield increased,especially the avail spikelets per spike,spike no.per hm2 and the dry matter accumulation during the period from jointing to filling increased significantly with the application of P fertilizer.so the yield of winter wheat increased significantly.The yield of treatment P3(135 kg P2O5/hm2) was higher than that of other treatments,which was 2 869.0 kg/hm2.But the yield of treatment P4(180 kg P2O5/hm2) decreased significantly,because of spike no.per hm2 and the dry matter accumulation during the period from jointing to filling decreasing significantly.The amount of N accumulation of winter wheat increased during the period from jointing to filling,but decreased by 13.4%-44.2% after filling.It increased the amount of N absorption with application of P fertilizer.Long-term application of P fertilizer increased soil organic matter and soil N,especially increased soil P significantly.The total P and available P of soil increased by 10.7%-64.5% and 234.6%-667.3% respectively.The yield and amount of N absorption of winter wheat were increased with long-term application of P fertilizer(45-135 kg P2O5/hm2).