Research On The Influence Of Soil Effect Of Water And Temperature And Maize Yield From Straw Stubble Mulching

In China, Maize is one of the main food crops, the northeastern region is the mainproduction area of maize. Irrigation in this region mainly depends on rainfall.But the unevendistribution of precipitation and the deterioration of ecological environment in recent yearslead to spring drought and summer floods in the maize’s growing season. Rising in the late19th century, conservation tillage technology, which took straw stubble mulching and low ornon-tillage as the main treatment measures, has aroused widespread attention in the variousregions of the world because it could improve the soil capacity of water-retention and water-storage.We did a lot of research on this.However due to the differences from crop types toregional climate, different conclusions were gotten from the same treatment.As a result, it wasurgent to do research on the straw stubble mulching methods applied in different regions.This paper, taking Shenyang as example and, explored the impact of straw stubblemulching on soil moisture and temperature and crop yields,combined the “Research.of strawstubble mulching farming on soil moisture and soil conservation mechanism” from Projectsupported by the Scientific Research Foundation of the Human Resource Ministry and theEducation Ministry for Returned Chinese Scholars, China ([2010]1174). Through datacollected of different straw stubble mulchings on soil moisture and tempreature, maize growthindicators and yield index by field test,soil moisture、 soil temperature and the evaporationchanges in the growth period under the condition of different straw stubble mulchings wereanalysed， differences of the impact from different straw stubble mulchings was explored,water consumption in maize different growth period and water use efficiency was calculated.The main achievements were obtained as follows:(1)During the growth period and the leisure period,especially under the condition ofheavy rain in leisure period, straw stubble mulching could reinforce soil water reservation forstraw mulching facilitated the precipitation infiltration and limited the evaporation at the sametime. However, the tendency to change of moisture content in the whole growth period wassimilar on the whole.(2) Under the condition of continuous small amount of precipitation: all treatmentsshowed that within the depth of60cm the moisture content increased while within the depthof60cm to80cm the moisture content of (Light scarifying straw mulching)QSG increasedand the rest decreased, but no change at all the (Traditional tillage)DZ’s. In the concentratedheavy rainfall case: the moisture content of all the treatment increased, and among the averageamount of the increased moisture content the (Straw and stubble full mulch)CJG’s was themaximum,which was34%of that of DZ’s,(Compacted soil and straw mulch)YG’s was the minimum,which accounted for24.5%of that of DZ.All of above showed that straw stubblemulching restrained precipitation infiltration in case of small rainfall and facilitated theprecipitation infiltration in case of heavy rainfall.(3) The average of the soil evaporation between plants of all the treatments dropped,compared to that of DZ.The most significant one was YG, the difference was28%.It showedthat straw mulching suppress the evaporation and the effect got greater as the densify of strawmulching became greater.(4) The influences on crop water consumption from straw stubble mulching were asfollows: during seeding stage, elongation stage,heading stage and grain filling stage, the waterconsumption of CJG was greater than that of DZ and especially in the heading stage thedifference would be30.73mm,which account for32%of the DZ’s consumption. In maturationstage, only the QSG’s water consumption more than DZ’s, other treatments are less than theDZ’s, which is6.59mm the largest value difference between (stubble cover) CG and DZ,accounting for32%of the DZ water consumption. Overall,the treatment of CJG and YG wasbest in reducing the water consumption.(5) In the seedling stage,the temperature of the depth of0to25cm showed thatCJG<YG<TG(Straw bar and stubble mulch)<DZ in general.The soil temperature of resttreatments showed that QSG>DZ>CG, especially within the10cm of the surface.That provedthat straw and stubble mulch were not good for the rise of the soil temperature whileminimum tillage and crushed stalk mulching were good for the the rise of the soiltemperature.The average of the soil temperature of different straw stubble mulchings showedthat these treatments made the temperature decrease and the degree varied. The soiltemperature of QSG and CG was close to that of DZ, but there was a big difference betweenthat of CJG and DZ which was as much as1.48℃.(6) The soil temperature of different straw stubble mulchings went low as the depthincreased but the variation differed from each other.The temperature of QSG and DZdecreased as the depth increased but difference of temperature became smaller and smaller.So did that of CG and TG but the difference was that the variation of the temperatureincreased at the depth of20cm.This was the same with that of YG and CJG while thechanging point was15cm.In a word, straw stubble mulchings make the soil temperaturedecrease and the variation grew as the depth increased of which the scope became greater atfirst and smaller later on.(7) The influences on emergence rate of maize from conservation tillage were that theeffect of minimum tillage was better than that of no-tillage while effect of no-tillage wasbetter than that of compacting.QSG was best at emergence rate of maize. The effect on LAI of straw stubble mulching was that QSG> DZ> CG>TG>CJG>YG,especially QSG, the greatestdifference between DZ’s was0.5,which was about12%of that of the DZ’s max.So QSG wasgood for the rising of LAI.(8)Through analysis,it could be seen that order of water utilization efficiency from highto low was TG、QSG、CG、DZ、CJG and YG. Though the yield of the treatments of TG andCGwere lower than that of DZ, their water consumption were also lower than DZ’s， so thatcomprehensive analysis of their WUE overreached that of DZ. It showed that straw stubblemulching influenced the yield, but it improved the water utilization efficiency for it increasedthe water keeping capacity and made the soil moisture content change very slower.