公顷产10000kg小麦氮素和干物质积累与分配特性

以泰山23和济麦22为试验品种，通过连续2年的田间试验，对单产高达10 000 kg hm^-2的小麦进行了施氮量和氮素吸收转运和分配特性的研究。在2006—2007年生长季，随着施氮量的增加，小麦籽粒产量先增加后降低，施纯氮240 kg hm^-2 (N240)和270 kg hm^-2(N270)处理的产量分别达9 954.73 kg hm^-2和10 647.02 kg hm^-2，比不施氮肥处理(N0)分别增加11.20%和18.93%。与N0处理相比，施氮处理显著增加了小麦植株氮素积累量、籽粒氮素积累量和开花后营养器官氮素向籽粒的转运量；随着施氮量的增加，成熟期小麦植株氮素积累量呈先增后降趋势，以N270处理最高；开花后营养器官氮素向小麦籽粒转运量和转运率先升后降，转运量以N270处理最大，为213.78 kg hm^-2；而转运率以N240处理最高，为67.98%。随施氮量的增加，小麦成熟期各器官干物质积累量、花后营养器官干物质再分配量和再分配率先增后降，均以N270处理最高；开花后干物质积累对籽粒的贡献率亦呈先增后降的趋势，以N240处理最高。2005—2006年的试验结果呈相同变化趋势。在本试验条件下，小麦产量水平达10 000 kg hm^-2时的适宜施氮量为240~270 kg hm^-2，可供生产中参考。

Characteristics of Accumulation and Distribution of Nitrogen and Dry Matter in Wheat at Yield Level of Ten Thousand Kilograms per hectare

Application of nitrogen (N) fertilizer is one of the most important cultivated measures to increase wheat (Triticum aestivum L.) yield in production. However, abuse of N fertilizer will not only reduce grain yield and economic profit but also cause environmental problems. The proper amount of N fertilizer applied in high-yielding production of winter wheat has been studied at the yield level of 9000 kg ha^-1. The objective of this study was to determine the effects of several N fertilizer rates on uptake, distribution, and translocation of nitrogen as well as grain yield, therefore, to suggest a reasonable application rate of N fertilizer in wheat production. Three rates of N fertilizer application (0, 180, and 240 kg ha^-1) without manure before sowing were designed in Experiment I in 2005–2006, only one treatment of N fertilizer (260 kg ha^-1) with 3 750 kg ha^-1 manure before sowing in Experiment II in 2005–2006, and six N fertilizer rates (0, 210, 240, 270, 300, and 330 kg ha^-1) with 3 750 kg ha^-1 manure in 2006–2007. Two wheat cultivars with medium protein content, Taishan 23 and Jimai 22, were used in the three experiments, i.e., Taishan 23 in Experiment I, Jimai 22 in the other two experiments. The results showed that the application of manure before sowing had minor effect in this study, and three experiments showed similar changing trends in N accumulation and translocation among various organs and growth stages as well as the grain yield. Take the example of Experiment III, with more input of N fertilizer, the grain yield first increased and later decreased during growth period compared with the control (no N fertilizer treatment), and the grain yields of N240 (240 kg ha^-1) and N270 (270 kg ha^-1) treatments were 9 954.73 and 10 647.02 kg ha^-1, respectively, by the increase percentages of 11.20% and 18.93%. Compared with the control, the nitrogen accumulation amount in plant and grain and the nitrogen translocation amount (nitrogen accumulation in vegetative organs at anthesis stage minus the nitrogen accumulation in vegetative organs at maturity, NTA) from vegetative organs to grains after anthesis significantly increased in treatments with N fertilizer application. With the increase of N fertilizer rate, the nitrogen accumulation amount in wheat plant showed a changing trend of first up and then down. The N270 treatment had the highest nitrogen accumulation amount at maturity. The NTA and nitrogen translocation efficiency (NTA/ nitrogen accumulation in vegetative organs at anthesis stage, TE) from vegetative organs to grain after anthesis also increased at first and then decreased. The N270 treatment had the highest nitrogen translocation amount, which was 213.78 kg ha^-1. The N 240 treatment had the highest TE of 67.98%. Similarly, the dry matter accumulation amount in various vegetative organs of wheat at maturity, the dry matter redistribution amount from vegetative organs to grain after anthesis, and the dry matter redistribution efficiency after anthesis were all largest in N270 treatment. Among the six N fertilizer treatments, the contribution of dry matter accumulation amount from vegetative organs to grains after anthesis was the largest in N240 treatment. The results of this study suggested that N fertilizer supplied at 240–270 kg ha^-1 is optimal in wheat production under similar conditions to those of the experiments to obtain the high-yielding level of 10 000 kg ha^-1.