| Increaseing maize yield is the fundamental way to solve the production and demand contradiction of maize and ensure food safety and animal husbandry in the Middle Reaches of Yangtze River. There were abundant climate resources, such as solar radiation, heat, precipitation and others, which were sutiable for maize growth. There were also abiotic, such as low temperature and waterlogging in spring, high temperature in summer and lower temperatue and lower solar radiation in autumn for maize growth, however. At the meanwhile, this region is not the main region for maize production in China, so the cultivation techniques for maize is weaken, and such as lower soil fertility filed, and fertilized not in time or enough for maize growth, and even planted in poorly population structure. So, the objective of this study were to,(1) Study the character of climate resource in the Middle Reaches of Yangtze River, and study their effects and determine the main affected factors on maize growth and yield formation, and so confirmed the suitable sowing date for obtained the high maize yield.(2) Ascertain the effects of controlled release fertilizer, N application by controlled release fertilizer under mulch filming and different plant population structure on maize yield formation, establish the optimized high yield culture technique mode for spring maize.(3) Investigate the characteristic of high yield and high resource use efficiency by different planting system, provided theoretical exploration and technical reserves for cropping systems adjustment in future in the Middle Reaches of Yangtze River. The results are as follows:(1) Studied and confirmed the effects of climate resources on maize yield formation, explicated the main climate factor on maize yield formation, and defined the suitable sowing date for obtained the high maize yield.There were a long suitable time, form March 10 to July 25, for maize sowing in the Middle Reaches of Yangtze River. In the suitable time, ther were a quadratic curve relationships between maize grain yield(GY) and sowing date(SD), and the coefficient of variability(CV) for GY and SD was high as 20.5%. Kernel wight(KW) were decreased firstly and the increased with SD, and the CV is 11.2%, meanwhile, ear number(EN), ear kernel number(EKN), ear spikelet number(ESN) and ear spikelet ripening rate(ESRR) were always decreased with SD, and the CV were 6.3%, 20.0%, 14.2% and 9.5%, respectively.By the correlation and stepwise regression analysis, we confirmed the main climatic fatores affected on maize yield formation, as follows, killing degree days(KDDES) and days of maximum temperature(MTmax) higher than 30 ℃(D30ES) from emergence to silking(ES), and total solar radiation(TSRSM) from silking to maturity(SM) and mean daily temperature difference(M△TEM) from emergence to maturity were the main climatic factors affected on GY. D30 SM and its ratio to days from silking to maturity(RD30SM) were the main climatic factors affected on KW. D30 ES and TSRSM during SM growth stage(TSRSM) were the main climatic factors affected on EN. M△TES and TSRES during ES growth stage determined the EN build, while KDDES in this stage determined the ESN, but ESRR was determined by TSRSM and D30 EM. Mean temperature(MT), growing degree days(GDD), KDD and TSR determined the days of ES growth stage, and MTmax, GDD, KDD and TSR determined the days of SM growth stage, so the main factors affected on total days of EM growth stage were MTmax, MT, GDD and KDD.By the main goal to obtained the high maize grain yield, the suitable sowing date for spring maize was form March 22 to April 27, and June 25 to July 15 for autumn maize.(2) In order to comprehensive arrangement of maize and rice production, built spring maize and later rice plating system in a year. The cereals yield, use efficiency of GDD(UEGDD) and use efficiency of SR(UESR) could increased by 22.94%, 4.06% and 14.92%, respectively, by alter duble rice to maize-rice planting system, while PFPN reduced by 2.10%. Compared to double rice planting system, double maize system could increase cereals yield, UEGDD and UESR by 21.73%, 2.93% and 19.10%. In double maize planting system, planting early and middle maize hybrid in spring with middle hybrids in autumn could obtain maize high yield was 16 528 kg hm-2 in a year.(3) Studied and clarified the effects of controlled release fertilizer, N application by controlled release fertilizer under mulch filming and different plant population structure on maize yield formation, establish the optimized high yield culture technique mode for spring maize.The maize grain yield were stabled with fertilized slow/controlled release fertilizer in the Middle Reaches of Yangtze River. And sigle basal fertilization could reduce input by 1 200 yuan hm-2, with economic income increased to 1429-1725 yuan hm-2, economic efficiency increased by 13.56%-16.12%.Photosynthetic characteristics parameters were optimized by increasing N application by controlled release fertilizer, and speeded kernel filling, increased KW significantly, and GY increased by 6.80%~24.66%. Mulch filming promoted maize growth, inlarged leaf extension and decreased the speed of leaf senescence after silking. Mulch filming increased EN, EKN and KW significantly, and GY increased by 7.16%~21.19%. The lose of soil available N were decreased with mulch filming, and increased soil available N contents in 0-40 depth. With N uptake and accumulation increasing, PFPN and ANUE were increased 18.30%~31.67% and 25.83%~56.80%, respectively, with mulch filming. Take incount, spring maize could obtained grain yield of 8845 kg hm-2 with optimized N application was 162.6 kg hm-2 under mulch filming by slow/controlled release fertilizer, and that for no mulch filming filed were GY was 7298 kg hm-2 and optimized N application was 186.9 kg hm-2. So, mulch filming could decreased optimized N application 24.3 kg hm-2, and increased GY 1547 kg hm-2, increased by 21.2%.Spring maize GY increased significantly at first and then decreased with increasing planting density in the Middle Reaches of Yangtze River. Spring maize GY was increased firstly and then decreasd with planting density increasing by equal row space(60+60 cm) and borad row space(120+120 cm), while GY was increased to a plantform and then stable with planting density increasing by narrow and borad row space(40+80 cm). Spring maize population structure were optimized by planted with narrow and borad row space, and in this molde, plant density could increased by 967 plants hm-2, and obtained higher yield of 10 888 kg hm-2, increased by 8.89%. In conclusion, this study integrated the “The spring maize high-yield culture technique ” and “Annal ditch, no-tillage, dislocation, single basal fertilization” high yield double maize planting system. |
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