| Apple-peanut intercropping system is a main agroforestry configuration mode in the Loess Plateau of Western Shanxi Province,but the unreasonable design of the intercropping system often leads to the decrease of the growth and yields of the crops.The purpose of this paper is to quantitatively analyze the microclimate of fruit-crop intercropping system and the impact of the microclimate on the growth and yields of crops,and to provide theoretical support for the optimization of local fruit-crop intercropping system.In order to stydy the microclimate effect of intercropping system and its impact on peanut,a seven-year-old apple-peanut intercropping system were chosen as the research object,and a peanut monoculture system is chosen as control.The research has conducted in below procedures:First,setting root barriers between crops and trees to block the extension of the root system.Then,monitoring the microclimate factors(including photosynthetically active radiation,air temperature,wind speed and relative humidity)of crop rows which are at different distance from tree rows,and calculating contribution rate of different microclimate factors on net photosynthetic rate and yield of peanut by using multiple stepwise regression analysis.The main results are as follows:(1)Effects of apple-peanut intercropping system on microclimate:Canopy shade of trees had a negative effect on PAR of crops,The relative PAR of intercropping system are 49.39%-88.01%,and the closer crop row was to tree rows,lower the PAR was.The relative air temperature of intercropping system are 92.74%-97.32%,and the closer crop row was to tree rows,lower the air temperature and daily temperature range were.The relative relative humidity of intercropping system are 112.36%-123.72%,and the closer crop row was to tree rows,higher the relative humidity was.The relative air wind speed intercropping system are 92.74%-97.32%,which is significantly less than monoculture system(P<0.01).(2)Effects of apple-peanut intercropping system on photosynthetic characteristics of peanut:The relative net photosynthetic rates(Pn)of intercropping system are 58.99%-90.97%,and the closer crop row was to tree rows,lower the Pn was.The diurnal changes of Pn of R1,R2,R2 and R1 were all single peak,while R3 and R3-appeared double peak because of the midday depression of photosynthesis.The modified rectangular hyperbola model fitted the photosynthetic data of peanut well,The light response curve can be divided into three different stages:the Pn increases linearly,the Pn increases with a decreasing growth rate and the Pn change slightly.The decrease of PAR can promote the SPAD of peanut,and the closer crop row was to tree rows,lower the SPAD was.The contribution rates of PAR,air temperature and relative humidity to the Pn of peanut were 62.48%.20.71%,16.45%.(3)Effects of apple-peanut intercropping system on plant height,biomass and yield of peanut:Compared with the monoculture system,the plant height of peanut in intercropping system were decreased by 2.26cm-7.02cm(flowering period),2.53cm-8.03cm(pod bearing period),4.09cm-9.03cm(mature period),respectively.Moreover,the closer crop row was to tree rows,lower the plant height was.The dry weight of root,stem and leaf in three phenophases of intercropping crop compared with CK were reduced by 1.06g-1.71g,3.70g-5.48g and 4.71g-8.03g,respectively.The closer crop row was to tree rows,lower the dry weight was,and the gap of overground part is larger than underground part.The microclimate of intercropping system had a negative effect on crops yield,the yield of intercropping system had fallen by 39.44%compared with monoculture system,and the closer crop row was to tree rows,lower the yield was.The contribution rates of PAR,air temperature and relative humidity to the yield of peanut were 53.48%,30.07%and 16.45%.According to the results,reasonable pruning of fruit tress should be taken combined with the phenological phasel;and adjusting the distance between crops and fruit trees should be considered. |
PDF Full Text Request