Reaearch Of Water Adaptive Plant With Maizes And Water Use Efficiency

In new century,we are faced with the challenges of both watrer safe and grain safety in our country.It is needed to raise crop yield under the condition of limited water resource by increasing water use efficiency(WUE).Water saving and production increasing has become the major content of the north agricultural sustainable development in the future.Biological water saving raises output and WUE with biological function which has a little input and high benifit and big potential.It suits the national conditions of our country. Corn is the major crop planted in Shanxi.Drought is the chief restricting factor of corn production,it is greatly meaningful to plant corns with the biological measure of water saving.There are mainly two biological ways available to save water:1 as the point of hereditary view,establishing appraisal system and screening suitable breed to raise WUE;2 from the environmental angle,studying the law of water need and find out the quota of non ample irrigation to realize the balance of WUE,output and water consumption.This research have studied the possibility of realizeing biological water saving under current condition by analysising sprout experiment indoor combined with field irrigation research.Through the method of simulateing drought artificially with PEG solution,the difference of drought resistance of the different breeds in germination was studied to screen drought resisting breeds in indoor sprout experiment in order that the need of sowing seeds and sprouting was satisfied in the condition of soil drought and entropy shortage in the spring of Shanxi.Field experiment is designed with split district,that is to say,irrigating is mainly group,breed is associate group.The law of water need and consumption of spring corns,the effect of drought intimidation on the corn growth and physiological proterties and yield,the drought resistance of different breed and the water suitabiltiy in different moisture condition were studied to confirm the preponderant breeds in different moisture conditions and the relationship between the yield and the WUE and water consumption.The results showed that:1 There was a remarkable discrepancy in the drought resistance in germination,among different maize breeds.The breeds with high drought resistance has higher sprout index of drought resisting and vigour index of drought resisting which can still keep higher Germination vigor and rate and less effect on dry weight of seedling and radicel and transformation rate of stored substance under water stress.Xianfeng 3,Dongdan 60,Pinyu 3 and Nongda 108 were breeds which can endure drought highest.Shenyu18, Sanbei 6,Jindan 42,Zhongyu 9 and Ludan 6006 were breeds which can endure drought comparatively higher.When drought resistance of a large quantity of breed in germination was identified,we used PEG simulating drought to to carry out selection with the sprout and the vigour index of drought resisting as index,which could reduce working strength and raise working efficiency.The vigour index of drought resisting was put forward on the base of the sprouting index of drought resisting,with the length of seedling was also considerd,which could reflect well the difference of seed vigour and seedling growth among various breeds under water stress.It could be the selection method of identifying the drought resistance in sprout stage of corn.2 There were remarkable difference of yield among different breeds treated with different irrigation quantity.In the condition of drought,limited irrigation might make the output increase in great degree.The order of the index of drought resisting has no discrepancy in different moisture condition, which was related only apparently with the output of dry land.The index of drought resisting leaned to the selection of breeds with steady yield,whereas the drought resistance under arid condition did not coincide completely with the highyield in different moisture condition.In this experiment Zhongyu 9 with highest index of drought resisting has strongest drought resistance whose yield was as high as 5029 kg/hm₂ with no irrigation.But the output is comparatively lower in plenty water condition.The yield of Zhongyu 9 was 6535 kg/hm₂ in middle quantity irrigation condition whose highyield was low with no sufficient use of water.Since the water adaptive range of different breed were different,the range and the order in the output change in the different water condition (irrigation) were different.The water adaptive index put forward in the paper might reflect this change very well and trend to select the high-yield kinds.Considering the huge discrepancy of farmland's moisture condition of main grain produces district in the arid half arid region of our country,it was more meaningful to screen breeds water adapted than to screen breeds drought resisting merely as for the breed experiment taking gains economic output as purpose.The water adaptive index has more actual meaning with the virtue of better operability and intuitionistic result easy to compare and analyse.There were really several breeds with higher yield in various moisture conditions in this experiment,some of which had higher increase production and highyield potential with irrigation and even were able to keep higher yield when being short of water,exhibiting certain drought resistance. Thereinto Shenyu 18 had a extensive water adaptability whose output was 4873 kg/hm₂ with no irrigation and 7836 kg/hm₂ in the condition of moderate quantity irrigation which reached or was close to the acme in the test that had realized the purpose of water saving and high yield.3 For spring corn planted in half arid and moist districts where had a comparatively adequate precipitation,in the point of gross,precipitation could satisfy corn growth needs,but it was unequal in space-time distribution. In specific time or bearing stage,the disproportion between water requirement and consumption might excess the cushion of soil reservoir and crop's endurance,which caused staggered arid stress and needed to irrigate. Irrigation not only increased crop water consumption merely,what was more it improved the coupling between crop water consumption and need,so as to alleviate the staggered arid caused by unequal precipitation in space-time distribution and increase production and adjust the capacity of soil reservoir storage.Thus the smaller and moderate quantity irrigation might raise output and the efficiency of water use obviously.4 The discrepancy of water consumption different breeds with the same disposal was not large,which was smaller than the discrepancy of irrigation quantity,whereas the discrepancy of yield was huge.In different moisture condition,the discrepancy of WUE was caused mainly by change in yield,so sub-district WUE was correlative positively with the water adaptive index or yield.The WUE of Shenyu 18 reached the high point 18.83 kg/hm²Â·mm with moderate irrigation in this experiment.Smaller quantity irrigation,higher output and WUE had realized at the same time.Through the analysis of yield and WUE We had come to the conclusion that the yield and WUE increased early along with water consumption and then reduced.Limit output,limit WUE and moisture flexible coefficient decreased with the increase of water consumption.WUE summit and Y summit could not realize at the same time,WUE reached the summit earlier than Y.That was to say efficiency reached optimum followed by effect.The coefficient of moisture flexible e could be differentiating index.When e=1, limit WUE was 0.At the time WUE reached summit.After that output increased with the increase of water consumption,wherease WUE reduced with the increase of water consumption.When e=0,limit output was 0, output reached highest point.As for the goal of irrigation,irrigation quota of biggest output could be work out according to the settlement of polar coordinate of yield-irrigation water function.The irrigation quota needed to determine according to the price of corn and water to realize biggest profit.When the added value produced by irrigation was equal to the value of inputed water itself,the quantity of input was economic and optimum.At the time limit profit was equal to limit cost.The model analysing irrigation cost-profit could be determined.When the value of irrigation water was 1.7 Yuan/ton and that of corn was 1.4 Yuan/kg,Shenyu 18's biggest output was 7896 kg/hm₂ and net profit was 5,456.67 Yuan/hm₂ when the quantity of irrigateion was 1086.98m3/hm₂.When the quantity of irrigateion was 854.99m3/hm₂,the yield was 7,755.24 kg/hm₂ and the net profit was 5,653.85 Yuan/hm₂ which was biggest.