直播冬油菜干物质积累及氮磷钾养分的吸收利用

 【目的】了解高产直播冬油菜的养分吸收和利用规律。【方法】高产栽培条件下，在冬油菜整个生育期内定期取样，测定油菜各部位干物质量和养分含量，计算各生育时期氮、磷、钾养分积累量，明确甘蓝型冬油菜在4 500 kg?hm-2产量条件下的干物质积累及氮、磷、钾养分吸收利用规律。【结果】直播冬油菜总干物质积累呈“S”形曲线，表现为薹花期＞苗期＞角果成熟期。根、茎、绿叶、落叶的干物质量分别在播种后185、200、130、230 d达最大值，干物质量分别为2 286、5 450、2 306、2 162 kg?hm-2。各器官氮含量（籽粒除外）随生育时期的推进逐渐降低，苗期变化平缓，蕾薹期后降幅较大。茎、绿叶中磷含量苗期略有上升，蕾薹期后迅速降低。根、落叶、角壳中磷含量则持续下降。根、茎中钾含量在苗期波动较大，蕾薹期后迅速降低。叶片中钾含量在苗期略有降低，其后一直稳定。落叶中钾含量一直波动变化，无明显规律。氮、钾的积累规律相似，出苗后持续增加，花期达最大值，而后略有下降，两者积累量均表现为苗期＞蕾薹期＞花期。整个生育期磷积累量持续上升，表现为角果期＞苗期＞薹花期。高产栽培条件下直播油菜N、P、K最大养分需求量分别为217.6、39.9、219.8 kg?hm-2，需求比例为1.00﹕0.18﹕1.01。【结论】除落叶和生殖器官外，各器官干物质积累量、养分含量、养分积累量均呈现苗期升高花期后降低的变化趋势。根、茎、叶中的部分养分在花期后会转移到籽粒中，保证直播冬油菜花期前充足的养分供给是高产的前提。

Dry Matter Accumulation and N, P, K Absorbtion and Utilization in Direct Seeding Winter Oilseed (Brassica napus L.)

【Objective】An experiment was conducted to study the law of nutrients absorption and accumulation for high yield direct seeded winter oilseed rape (Brassica napus L.).【Method】In order to know N, P and K absorption and utilization of winter oilseed rape which produced 4 500 kg?hm-2 seeds under high yield cultivation patterns, dry matter accumulation and nutrient content and nutrient accumulation in different organs were tested at regular intervals.【Result】Results showed that dry matter accumulation appeared S-type curve and showed as blooming period＞seedling period＞pod period, and roots, stems, green leaves and defoliation reached maximum at 185, 200, 130 and 230 days after seeding and get 2 286, 5 450, 2 306 and 2 162 kg?hm-2 respectively. N content kept stable in seedling period and decreased sharply after flowing period in all organs except seeds. P content increased slowly in seedling period and decreased quickly after flowing in both stems and leaves and decreased constantly in roots, defoliation and shells. K content in both roots and stems changed significantly in seedling period and decreased after then. K content of green leaves decreased in seedling period and kept steadily during other periods. K content in defoliation changed significantly and irregularly. Both N and K accumulation reached maximum in blooming period and decreased little after then. Accumulation of N and K showed as seedling period＞bud period＞blooming period. P accumulation increased constantly in the whole growth period and showed as pod period＞seedling period＞blooming period. The maximum requirement of N, P and K under high yield cultivation were 217.6, 39.9, and 219.8 kg?hm-2, respectively, and the ratio of 1.0﹕0.18﹕1.01.【Conclusion】Dry matter accumulation and nutrient content and nutrient accumulation showed as a falling after rising in each organs except defoliation and reproductive organ. Accumulation of N, P and K in roots and stems and leaves can be recycled in different degrees. Sufficient fertilizer supply before blooming period in winter oilseed rape is the guarantee of high yield.