麦稻轮作高产条件下施磷对土壤速效磷及作物产量的影响

Effect of phosphoric fertilizer application on soil available P and crop yield in wheat-rice crop rotation

经过 4年的田间定位试验 ,结果表明 ,在含磷量较高的土壤条件下 (速效磷在 2 5mg·kg-1以上 ) ,随着施磷量的提高 ,土壤速效磷含量明显增加 ,在土壤中有累积现象。后作利用前茬磷肥后效 ,土壤速效磷有降低趋势。水稻施磷 ,当季产量具有明显增产效果 ,而且磷肥残效亦可满足后茬小麦对磷的需求 ,产量亦可保持在较高的水平上。根据施磷后土壤速效磷的变化规律及作物产量结果分析表明 ,在麦稻轮作高产栽培条件下 ,水稻季施P2 O590kg·hm-2 为宜 ,小麦季施P2 O5135kg·hm-2 为宜 ,每年一次性施磷即可满足作物生长发育的需要。根据我们的研究结果 ,水稻季施磷可降低磷肥用量 ,并能保持稻麦两作较高的产量水平 ;根据北方稻区小麦播种采取带稻撒播而不利施肥的耕作特点 ,认为水稻季施磷在北方麦稻轮作区是一项有利的。

From 1995 to 1999, a field experiment was conducted with calcareous soil of high phosphorus content to determine most effective methed of the phosphoric fertilizer in a rice-wheat or wheat-rice cropping system. The results were: 1). With the increase of P fertilizer rates (0, 45, 90, 135 kg·hm -2 ) to rice or wheat, the available P content of the soil increased, and had a marked effect on the increase of the grain yield in present rice season. The residual effects of phosphorus applied to the succeeding crop wheat were significant, and maintained the higher grain yield of succeeding crop, but the available P decreased; 2). Under high yield condition of wheat-rice or rice-wheat period of crop rotation, the phosphorus application of 135 kg·hm -2 for wheat or 90 kg·hm -2 for rice were suitable. P fertilizer applied at one time each year to meet the needs on growth and differentiation of rice or wheat; 3). To come into a conclusion, the practice of supplying phosphorus in rice season could be decreased to 45 kg·hm -2 to maintain the higher grain yield of both rice and wheat. On the other hand, wheat was sown by broadcast sowing with rice growing in the rice cropping zone in North China. For this reason, application of base fertilizer was more difficult. Therefore, the application of phosphoric fertilizer was suitable for rice season.