滨海盐渍土抗虫棉养分吸收和干物质积累特点

Characteristics of Nutrient Assimilation and Dry Matter Accumulation of Bt Cotton(Gossypium hirsutum L.) in Coastal Saline Soil

以转Bt基因抗虫棉(Gossypium hirsutumL.)中早熟品种鲁棉研18和早熟品种鲁棉研19为材料,对黄河三角洲滨海盐渍土高、中、低产田抗虫棉的主要养分吸收、光合速率和干物质积累特点进行了研究。结果表明,中、低产田抗虫棉的主要养分吸收量显著低于高产田,而养分生理利用效率显著高于高产田。高、中、低产田抗虫棉的氮素生理利用效率分别为4.81、6.33和8.05kg皮棉kg-1N,磷素生理利用效率分别为28.57、40.06和50.48kg皮棉kg-1P,钾素生理利用效率分别为9.16、11.58和12.76kg皮棉kg-1K。养分吸收比例总体上N高于K,更明显高于P。中、低产田抗虫棉的净光合速率和生物产量明显低于高产田,皮棉产量也显著低于高产田,分别低12.44%和36.93%,但棉柴比显著高于高产田。表明滨海盐渍土中、低产田的盐分高而养分有效性和供应能力差,影响抗虫棉的养分吸收和光合作用,进而阻碍棉花生长发育和干物质积累。滨海盐渍土棉田经济施肥的原则是保证中、低产田的肥料供应,高产田重施P、K肥,低产田重施N、P肥。

The deficiency and disequilibrium of nutrient in coastal saline soil seriously hinder growth and development of cotton. It is urgent and necessary to study on changes of nutrient assimilation, nutrient use efficiency and dry matter accumulation of Bt cotton by measuring nutrient content and dry matter weight of different plant organs. And it can provide an important basis and guidance for economic application on fertilizers and nutrition improvement of Bt cotton in coastal saline soil. The experiments were conducted with two Bt cotton cultivars, spring cotton SCRC18 and short-season cotton SCRC19, in three types of coastal saline fields, high-, middle- and low-yield, in Yellow River Delta, Shandong province. The nutrient （N, P and K） assimilation, net photosynthetic rate （P,） and dry matter accumulation characteristics were investigated. The results showed that main nutrient up- take of Bt cotton in middle-and low-yield fields was significantly lower than that in high-yield field. But nutrient use efficiency in physiology （NUEp） in middle-and low-yield fields was significantly higher than that in high-yield field. Average NUEp of Bt cotton in high-, middle-and low-yield fields was 4.81, 6.33, and 8.05 kg Lint kg^-1 N, 28.57, 40.06, and 50.48 kg Lint kg^-1 P, and 9.16, 11.58, and 12.76 kg Lint kg^-1 K, respectively. Generally, N was higher than K, and much higher than P in nutrient uptake ratio. Pn and biomass yield of Bt cotton in middle-and low-yield fields were obviously lower than those in high-yield field. And lint yield in middle-and low-yield fields was by 12.44% and 36.93% lower, respectively, than that in high-yield field. However, the ratio of seed cotton to straw in middle-and low-yield fields was significantly higher than that in high-yield field. Further analysis indicated, there were high salt content, ：and poor availability and supply capacity of nutrient in middle- and low-yield fields in coastal saline soil. These factors inhibited the nutrient assimilation and photosynthesis, and hindered growth and dry matter accumulation of Bt cotton. It was recommended that low-and middle-yield fields should have precedence over high-yield field in fertilization. It was also suggested that more P and K fertilizers should be applied in high-yield field, while more N and P fertilizers should be applied in low-yield field, according to characteristics of nutrient assimilation of Bt cotton and soil fertility in coastal saline soil.