Studies Of Precipitation Characteristics In Corn Growth Period And Its Impact On Corn Yield In Wanjiang Region

Water is the restrictive factor of agricultural production, agricultural productionrequired for water resources mainly depends on natural precipitation, so how much aregional precipitation, precipitation of the stability is very important to agriculturalproduction, such as insufficient rainfall can result in dry, but too much or toocentralized precipitation, often have serious waterlogged disaster. Corn is a high-yieldcrops, due to the influence of traditional agricultural production and so on, Wanjiangregion less cultivation, but with climate change, corn cultivation technology and thediversity of use, the Wanjiang region in recent years, corn cultivation area of rapidlyexpanding at an annual rate by about20%per head. Corn like water resistance notwaterlogged, Wanjiang region precipitation characteristics of large and concentrated,may expand adversely influence of maize in the region. In Anqing region, as arepresentative of the Wanjiang region using precipitation in1960-2010, maize yielddata, etc., by adopting the method of wavelet analysis and method of moving averagepoints during the maize growth period in the region of precipitation is studiedcharacteristics and its effect on maize yield, for the smooth development of cornindustry in the region to provide scientific support. Among them, the climate of cornyield by using moving average method, the precipitation variation during the usingwavelet analysis method, the change rule of corn production employment screening,climate and the growth period of the precipitation model structure by adopting themethod of stepwise regression. Specific results are as follows:(1) Almost51years Anqing area relatively frequent alternating positive andnegative climate yield sequence, comes at a time (climate) on increasing biggest yearappeared in1965, to55%, negative (production) climate year minimum appeared in1999, reached43%, among them climate production date has1963,1971,1972,1974,1976,1978,1979,1984,1984, the production of the year is1960,1967,1967,1983,1999. Due to the different year trend yield, absolute climate yield and relative yield ina different climate, one of the biggest output for1976years, production of up to1252kg/ha, cutting production in1999, the maximum productivity is1582kg/ha,51yearsof climate yield262kg/ha on average. This suggests that the impact of climate factorson the corn production region significantly, it could also be the important reason forthe corn industry in the region smaller. Using quadratic polynomial fitting trendoutput model for: Yt=1.0318R2-0.4912T+2070.7.type Yt represent the trends in the production, t represents the s series, including R2=0.6164, the model shows thatthe corn in the region’s overall production level is low, but in the short term there isgreater potential to increase production.(2) The Anqing region almost51years corn from sowing to seedling stageprecipitation includes multiple different scales, the periodic change of the formationof oscillation center, plus or minus alternate with various scales of s and exist obviousinterannual changes. jointing stage-heading stage on14a time scale precipitationcycle oscillation very significantly, the scale of the change in the whole period has avery strong signal; Precipitation in the heading stage and filling stage8a timescaleperiodic oscillation are very significant; Grouting period-ripening periodprecipitation less period has not ended, but contour gradually tend to be closed;Ripening period, mature period precipitation in6a scale,1960-1978, not at all, havemore obvious after1978cycles, on8-16a scale, has obvious cycles from1960to1983, after1983, not at all. Curve of rainfall between the interannual change is big,high, the frequency of the wave shows that rainfall between the interannual andabundant alternate frequently, drought and flood disasters occurred frequently, whichtallies with the characteristics of climate yield of corn and show that precipitation isone of the important factors affect maize production in the region.(3) The use of SPSS to precipitation variation during the time sequence change,fitting equation respectively in each growth period of precipitation change: fromsowing-seedling y=0.1516T+123.59; jointing stage-heading stage y=2.2T+158.46; heading stage-filling stage y=0.095T+56.028; grouting period-ripeningperiod y=1.1T+72.388; ripening period-mature period y=-0.772T+103.48; thewhole stages y=0.5612T+102.79; From sowing-seedling stage and jointing stage-heading stage two combined into y=1.1763T+141.02. According to simulationresults, this paper studies the period, in addition to the ripening period, mature period,the other precipitation in growth period are increased.(4) The linear trend method is selected in Anqing region nearly51a climatechanges in rainfall time series in combination with maize production were analyzed,and the t inspection method of tendency is significant. Results show that corn fromsowing-seedling stage precipitation and precipitation-jointing stage and headingstage t value <0.0001by95%confidence interval, passed the test of significance, andprecipitation change trend and corn production climate change trend is roughly same,namely, the area of corn from sowing-seedling stage and jointing stage-heading stage key growth period of maize. Climate with corn yield as the dependent variable,five stages, the precipitation in the whole stages as the independent variable stepwiseregression, the regression equation is: y=411.948-5.558r1+4.381r2, r1forprecipitation in the whole stages of corn, r2is heading stage-grouting periodprecipitation. Climate yield and the growth period of the precipitation regressionequation shows that the heading stage-the growth period of filling stage is moreimportant, it has to do with from sowing to seedling and determined by the t testresults do not match-jointing stage and heading stage, the problems worthy of furtheranalysis.(5) In Anqing region, the analysis of the maize growth period precipitation in1960-2010, the area of corn for from sowing to seedling stage and reproductive stage-jointing stage and heading stage; Based on maize growth period average rainfall andflood and standard deviation is divided into five level, from sowing to the seedling atdifferent levels of precipitation scope of waterlogging respectively:>217.7mm,partial waterlogging:157.6-217.7mm, normal:97.6-157.6mm, the partial drought:37.6-97.6mm, drought:<37.6mm. At all levels-jointing stage and heading stage ofprecipitation scope of waterlogging respectively:>407.6mm, partial waterlogging:279.7-407.6mm, normal:151.7-279.7mm, the partial drought:23.8-151.7mm,drought:<23.8mm. According to the data from1960-2010, Anqing region of corn-the seedling stage and jointing stage to heading stage of waterlogging years accountedfor15.7%and11.8%of the total number of years, accounted for5.9%5.9%of thetotal number of years and dry years, Anqing waterlogging years appear slightly morethan the risk of drought. And partial waterlogging and drought year accounted for15.7%,13.7%and41.2%,13.7%respectively. So must to focus on corn departed.