| Field experiments were conducted during 2008～2009 in lingxian experimental station of Chinese academy of agricultural science,(located in Huang-Huai-Hai area of north China).The objective of this research was to find integrated cultivation techniques in winter wheat with high yield and high resources utilization efficiency, water-saving is the concentration. It included three experiments. The first experiment was about critical period of delayedsowing in winter wheat responsing climate chang and water-saving demand. The second experiment was about water-saving scheme in winter wheat. The third research was about N application rates under water-saving irrigation in winter wheat. Through one year study got these conclusions:(1)In 2008, accumulated temperature before winter of october 10 treatment (D10)was 581.4℃, october 15 (D15)was 501.4℃, october 20(D20 )was 406.3℃, october 25(D25) was 329.8. D10 treatment belonged to middle-delayedsowing wheat, D15 treatment belonged to delayedsowing wheat, D20 and D25 treatments belonged to exceedingly delayedsowing wheat .This difference had signifigant effects on wheat seedling before winter. Wheat of D10 and D15 treatments formed 4～5 leaf ages, 3～4 tillerings, 3～4 secondary roots before winter. Plant and population were srong and proper , this was the base of safely overwintering and high yielding. Wheat of D20 and D25 treatments had zero tillering and secondary root before winter, plant and population were small and weak. Colony spike numbers,grain yield,nitrogen uptake of D10 and D15 treatments were signifigant higher than D20 and D25 treatments. Soil water consumption of D10 and D15treatments were higher than D20 and D25 treatments, but water use efficiency,N uptake efficiency,N production efficiency of D10 and D15treatments were also higher than D20 and D25 treatments. Proper delayedsowing is optimum sowing model in order to cope with climate change,defense freeze injury and resist drought. According to statistics of Lingxian temperature date, accumulated temperature before winter from october 10 to october 15 were between 450～580℃. So we infer that this period is feasible delayedsowing days in general years. Refering to colony spike numbers 7.50×106/ha, basic seeding numbers shoud be control in 2.55～3.00×106 /ha..(2)During sowing to jointing stages, under 42 mm precipitation condition, available water content of 0～40cm soil layer decreased significantly, 0～40cm soil layer of all treatments (except wintering and jointing treatment) got serious water stress, while wintering and jointing treatment only got light water stress. Serious water stress before jointing stages remarkably affected root to absorb water in deep soil layer and photosynthetic rate of wheat in late stages. With increase of irrigation times, total water consumption increased, but the percentage of soil -water consumption and precipitation consumption decreased. Under light water stress condition, stomatal- conductivity decreased, consequently reduced transpiration rate, but preserved the net photosynthetic rate, so WUE of leaves increased. Irrigation at jointing stage significantly increased N uptake efficiency and N production efficiency, adding other irrigations had no significant elevated effect, moreover, increasing irrigation in later stages raised soil NO-3_N lost probability.There were conic relationships among grain yield, WUE and water consumption, but the two conics did not have the same variation tendency. A point of intersection at 360mm water consumption was found , which indicated the best combining site of grain yield and WUE. Grain yield of wintering and jointing treatment was 7753kg/ha, which increasing 40.2% compared to no irrigation treatment. WUE of wintering and jointing treatment was 1.9kg /m3, which did not differ with no irrigation treatment. So wintering and jointing treatment was the best water-saving and high yielding treatment this year.(3)N application significantly increased spike numbers and per spike grains of winter wheat, meanwhile the effect on thousand-grain-weight was not significant. Relationships among grain yield,N uptake and N application rates were parabolics, when N application rates exceeded 240 kg/ha, grain yield and N uptake reduced with increase of N application rates. Soil NO-3_N was founded in 0～20, 20～40, 40～60, 60～80, 80～100 cm soil layers after raising stage of winter wheat. Soil NO-3_N contents decreased with increase of soil layer depth for the same treatment; different treatments in the same layer, NO-3_N contents increased with increase of N application rates. Soil NO-3_N accumulations decreased with winter wheat growth going forward. N0 and N120 treatments appeared NO-3_N efficiency, respectively after jointing stage and anthesis stage. In harvest stage, residual N in 100 cm soil layer was the main part of surplus N, lost N accounted for little percentage. With increase of N application rates, N utilization efficiency and Nagronomy efficiency appeared downtrend, while N residue efficiency appeared uptrend. Under this experiment condition, N application rates from 180 to 220kg/ha can have good combinations of grain yield,N utilization efficiency and N residue efficiency. So 180～220 kg/ha were ideal N rates levels considering both economic benefit and environmental benefit.In conclusion, according to 05～08 Ling Xian weather data statistics, If seeding date is in october 10 to 15 , accumulated temerature before winter was between 450～580℃, these days are proper seeding date in Huang-Huai-Hai area, and referring to 7.50×106/ha spikes, basic seeding numbers shoud be control in control in 2.55～3.00×106 /ha. If carry out one irrigation, irrigation should be arranged at water critical period, that is jointing～flagging stage. If carry out twice irrigations, there are four combinations, irrigation at wintering and jointing, irrigation at raising and booting, irrigation at jointing and anthesis, irrigation at jointing and grouting. According to precipitation choose the optimum irrigation times. Under water-saving irrigation, N application rates from 180 to 220kg/ha can have good combinations of grain yield,N utilization efficiency and N residue efficiency. So180～220 kg/ha is ideal N rates levels considering both economic benefit and environmental benefit. |
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