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Study On The Relationship Between Distribution Of Microclimatic Factors And Wheat Yield In Farmland Shelterbelt

Posted on:2013-12-22Degree:MasterType:Thesis
Country:ChinaCandidate:X T ZhangFull Text:PDF
GTID:2230330395981438Subject:Science of meteorology
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Farmland shelterbelt is a plantation ecosystem that functions to prevent naturaldisasters, improve the climate, hydrology, soil conditions, create situations conducive tothe growth of crops and breeding of livestock to ensure the high and stable yield ofagriculture and animal husbandry, and offer much convenience to human lives. With thefarmland shelterbelt in Guoyang county as the subject, this paper researches on theregularity of distribution between microclimate factors and crop yield within Huaibei plainfarmland shelterbelt, analyzes the effect of microclimate factors on crop yield, usesSPSS18.0software to filter out the significantly related microclimate factors toestablish regression models and then build a quantitative relationship betweenmicroclimate factors and crop yield, and provides a valid basis for sensibly creatingfarmland shelterbelt. The main conclusions are as follows:(1) Variation is found in the distribution of farmland shelterbelt microclimate factors,depending on the distance from forest, and a more obvious change is observed within theforest0~5H range. At shelterbelt near the forest edge, the wind speed, temperature and soilmoisture content are relatively lower compared with the other observation points furtheraway from the forest, and in shelterbelt, the minimum value of relative wind speed, relativetemperature, and relative soil moisture are observed at the observation point near the forestedge, with86.87%,91.34%, and87.71%, respectively. However, the relative humidity ishigher at shelterbelt near the forest edge, with a maximum relative humidity of113.03%at0.5H away from the forest. Therefore, due to the impact of shelter belts, the extent ofdecrease in the wind speed and the extent of increase in the relative humidity are mostobvious near the forest edge. At shelterbelt within the forest7~20H range, the wind speed,temperature, relative humidity, and soil moisture content show a constant tendency. Exceptthe relative humidity in the shelterbelt, there are significant difference for the wind speed,temperature, and soil moisture content at different places away from the forest.(2) There are also variations in the distribution of growth index of wheat in thefarmland shelter forest, depending on the distance from forest. Studies have shown that theHuaibei regional shelter belts have a significant “threat” effect, owing to which, away fromthe forest0~1H range, the wheat plant height, panicle length, grain weight, and yield arelower compared to the more distant observation points away from the forest. The decline ofwheat yield is most obvious, with67.24%of the average yield in shelterbelt for the places 0.5H away from the forest. The declines of spike length and grain weight are also obvious,with83.92%and88.71%of the average in shelterbelt, respectively. Within the forest3~7Hrange, the growth index of wheat are higher than the average in the shelterbelt. Themaximum value of relative plant height, relative ear length, relative grain weight, andrelative yield are107.63%,107.25%,105.12%, and127.76%, respectively, of the averagein the shelterbelt. It can be seen that the most obvious increase is in wheat production.Away from the forest13~20H region, except the significant decline in wheat productionin the shelterbelt, wheat plant height, ear length, and grain weight gradually become steady,regardless of the distance of each observation.(3) Regression analysis is conducted to fit a multiple regression equation by theselection of wheat grain weight and microclimate factors. The results show that the relativegrain weight of wheat increases with the increase of relative wind speed and relative soilmoisture content at the observation places, with the effect of soil moisture content beingrelatively significant and that of wind speed being relatively minor. In shelterbelt, every10%increase of soil moisture and wind speed leads to8.43%and1.06%increase of grainweight, respectively. Therefore, near the forest edge where the "threat" effect is obvious, itrecommends appropriate irrigation and mining root pruning trench, in order to increase thewheat grain weight and minimize the “threat” effect to the least.
Keywords/Search Tags:Farmland shelterbelt, Microclimate, Growth index, Wheat Yield, Distributionpattern
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