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以黄淮冬麦区种植面积较大的普通小麦半冬性品种温麦 6号 (穗数型 )、徐州 2 5 (中间型 )为试验材料 ,采用不同措施于拔节前形成群体规模和特征有较大差异且有代表性的大、中、小三类群体 ,拔节后 (即中期 )对各类群体进行 4种不同施氮量处理 ,重点研究不同类型群体中期施氮肥的调控效应。结果如下 :不同类型群体在中期因苗合理施氮可达到超高产或接近超高产的水平。但大群体中、后期生长不易调控 ,安全生产性差 ,在中、后期以控为主 ,特别是要控制中期的生长量 ,在控制叶源量的基础上 ,稳定适宜的库容量 ,提高粒 /叶比。中群体促控余地大 ,安全生长性好 ,产量潜力大 ,中、后期应在稳定叶源量的同时大力提高库容量。小群体中后期应以促为主 ,协同提高叶源量和库容量 ,大力提高群体的生长量。对氮素积累量、光合势、净同化率与产量的关系分析还表明 ,中群体中后期吸氮强度高而平稳、氮积累量适中、氮素的生产力高、粒 /叶比和净光合速率也高 ,是稳定实现超高产的理想群体
In this study, the semi-winter wheat cultivars Wenmai 6 (spike number) and Xuzhou 25 (intermediate type) with larger planting area in Huanghuai winter wheat were used as experimental materials, and the population size and characteristics were formed by different measures before jointing Large, medium and small groups with large difference and representativeness, after the jointing stage (ie middle stage), four kinds of nitrogen application rate were applied to different groups, with emphasis on the regulation effects of medium-term nitrogen application in different types of groups. The results are as follows: different types of groups in the medium-term due to rational use of nitrogen can reach the level of ultra-high yield or near-high yield. However, in large groups, the late growth is not easy to control and the safety of production is poor. In the middle and later stages, the control is dominated. In particular, to control the medium-term growth, on the basis of controlling the amount of leaf sources, stabilizing the appropriate storage capacity and improving grain / Leaf ratio. In the group, there is ample room for promotion and control, good safety and growth potential, and great potential for yield. In the middle and later stages, the amount of leaf sources should be stabilized while the volume of the storage should be greatly increased. Small groups in the late should be to promote the main, synergistically improve the amount of leaf source and storage capacity, and vigorously improve the growth of groups. The analysis of relationship between nitrogen accumulation, photosynthetic potential, net assimilation rate and yield also showed that mid-and late-stage nitrogen assimilation intensity was high and stable, nitrogen accumulation was moderate, nitrogen productivity was high, grain-leaf ratio and net photosynthetic rate Is also high, is the ideal group to achieve super high yield