| With middle gluten content winter wheat Yangmai 158 (Which was widely extended in the lower reaches of Yangtze River) as the testing material, the nitrogen regulation and relevant populations were studied. Three typical growth populations, e.g. small-sized population (with around 0.5 million tillers and main stems per 666.67 m2), medium-sized population (with around 0.7 million tillers and main stems per 666.67 m2) and big-sized population (with around 0.9 million tillers and main stems per 666.67 m2) were achieved at the elongation period by adopting different basal manure ratios. And four different nitrogen treatments (including 6.9kg/666.67 m2 N heavily adopted at the period of the 3rd leaf to flag leaf, 6.9 kg/666.67 m2 N used averagely at the period of the 3rd leaf to flag leaf and the period of flag leaf ,4.6kg/666.67m2 N adopted at the period of the 2nd leaf to flag leaf ,and no nitrogen utilization)were also used at the metaphase to investigate into the effects of the nitrogen utilization on the different types of populations. The main results were the following.1.The effects of the nitrogen adoption at the metaphase on the different types of populations were various. The smaller the population, the more significance the effects were. Higher yield(over 400kg/666.67 m2) was achieved under small populations by expanding them if more nitrogen was adopted earlier at the metaphase. As for the medium-sized populations, suitable amount of nitrogen were adopted (e.g. 4.6kg N /666.67 m2 adopted at the period of the 2nd leaf to flag leaf or 6.9kg N/666.67 m2 averagely used at the period of the 3rd leaf to flag leaf and at the period of flag leaf) to increase the nitrogen efficiency, reduce the risk of lodging and thus enhance the yield. As for the big-sized populations, the nitrogen efficiency was rather low and the populations had a higher risk of lodging. Nitrogen utilization at the metaphase had a profound effect on both the number of spikes and the number of grain per spike. As far as small-sized and medium-sized populations were concerned, the number of spikes and the number of grains per spike increased by more than 20 percent and thus the number of grains per 666.67 m2 increased by 30-60 percent. While big-sized population increased less 10 percent in the numbers of spikes and the number of grains per spike , 10-20 percent in the number of grains per 666.67 m2.2.Nitrogen utilization at the metaphase had different regulation effectson different types of populations. The bigger the population, the smaller effects were. The number of dead tillers and main stems of small and medium-sized populations were reduced significantly after the tiller peaking period by adopting nitrogen at the metaphase, which led to an improved population quality and more spikes. As for big-sized populations, the risk of lodging was increased.3.The dry matters of small and medium-sized populations were improved significantly by adopting nitrogen at the metaphase. As for the medium-sized population, the increment is based on the suitable population. While as for the small and big-sized populations, the increments are not quite ideal. Compared with non-nitrogen treatment, the dry matter increased by 216.5-335.1 (e.g. 38.1-59.0%), 233.2-318.2(e.g.31.1-42.4%), 105.7-176.5(e.g.l 1.3-18.9%) kg/666.67 m2 respectively in small, medium and big-sized populations at the ripening period.4.Nitrogen adoption at the metaphase had a profound effect on the grain quality of different types of populations. The natural grain weight and the flour content were increased under the bigger population if nitrogen adoption at the metaphase was postponed. Higher protein, wet gluten content and higher SDS value were achieved under the condition of small-sized population, medium-sized population with 6.9kg N/ 666.67 m2 used averagely at the growth period of the 3rd leaf to flag leaf and at the growth period of flag leaf and big-sized population with 6.9kg/666.67 m2 N used at the growth period of the3rd leaf to flag leaf. As far starch content i... |
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