Abstract:

To investigate the effects of straw returning amount on phosphorus vertical distribution in soil and maize yield in dryland of Northeast China， the random block design was used in maize cultivation experiment. The conventional fertilization was used as control （CK）； and different treatments of straw returning amounts were set， including 0.25， 0.50， 0.75， 1.00， 1.25 and 1.50 kg·m^-2. The contents of total phosphorus （TP） and available phosphorus （AP） in different soil layers （0—90 cm）， the cumulative leaching loss of leachate， and maize yield were determined. The results showed that the contents of TP and AP in soil decreased from top to bottom. Compared with CK， P migration decreased with the increase of straw returning amount. And the effect of straw returning amount on P migration was significant， which the contents of TP and AP in leaching solution significantly decreased with 12.93%~59.85% and 11.22%~46.28% of TP and AP， respectively. The yield of maize was significantly affected by straw returning amounts， and the highest yield was obtained when the straw returning amount was 0.75 kg·m^-2， which was 14.61% higher than CK. In conclusion， the straw returning field could increase the content of available phosphorus， decrease the leaching loss of soil phosphorus， and increase the yield of maize， which provided theoretical basis for the control of agricultural non-point source pollution.

Key words: straw returning, leaching, total phosphorus, available phosphorus, yield

摘要：

为探讨东北旱地秸秆还田量对磷素在土壤中垂直分布及玉米产量的影响，采用随机区组设计进行玉米栽培试验，以常规施肥为对照（CK），在常规施肥的基础上添加秸秆，设置秸秆用量分别为0.25、0.50、0.75、1.00、1.25和1.50 kg·m^-2。分别测定不同处理0—90 cm土层土壤中全磷（total phosphorus，TP）和速效磷（available phosphorus，AP）含量、淋溶液的累积淋失量和玉米产量。结果表明，土壤TP和AP含量随着土壤深度的加深逐渐减少。与CK相比，随着秸秆还田量的增加磷素向下迁移降低，秸秆还田量对土壤剖面磷素向下迁移影响显著；淋溶液中P含量显著减少，其中TP降低12.93%～59.85%，AP降低11.22%～46.28%。秸秆还田显著影响玉米产量，秸秆还田量为0.75 kg·m^-2时产量最高，较CK增产14.61%。综上所述，秸秆还田可以增加耕层土壤速效磷含量，减少土壤磷素淋失，大幅提高玉米产量，为东北旱地秸秆还田减少磷素淋溶、控制农业面源污染提供了理论依据。

关键词: 秸秆还田, 淋溶, 全磷, 速效磷, 产量