Effects Of Farmland Shelterbelt In Incident Light Quantity Change On Wheat Growth

Based on the measurement of farmland shelterbelt in plain area of the main climate factorsof photosynthetic active radiation，and wheat leaf area index， biomass, yield，variation oflight quantum change quantity with wheat growth stages were analyzed， discussed the effectin farmland shelterbelt forest for crops growth and yield，provided the theoretical basis forfarmland windbreak network selection of the plain area．(1) In the network during wheat growth periods PAR showed a single-peak curve，the firstpoint peak appeared in14o clock，the remaining in13o clock．In the first and second pointsthere were a significant difference in light intensity and control． In the network， the mostobvious changes of light intensity difference was in mature stage，the smallest difference wasin seedling stage．(2) In the shelterbelt network belt light intensity showed more distance from forest andlarger trend，the influence of beam intensity at1time of the tree height was no longerapparent；effects of windbreak on wheat during different stages were mature stage> fillingstage> blossom stage> seedling stage．(3) In the farmland shelterbelt the incident light quantity during different stages showedmore distance from forest and larger trends．Effects of different stages of shade were maturestage> filling stage> blossom stage> seedling stage． The cumulative amount differences ofwheat in seedling stage was a minimum during various points，the maximum was in maturestage；the accumulateed amount of light in filling stage were the highest．(4) In the farmland shelterbelt the LAI of wheat with distance from belt increasing showeda trend of increasing．In the whole growth period of wheat， the leaf area index showed a trendincreased firstly and then decreased with the stages changing， achieved the highest in blossomstage． (5) In the net of farmland shelterbelt during different stages of intercepted light showedfrom the forest more far and larger trends， wheat intercepted light followed by filling stage>blossom stage> mature stage> seedling stage．Wheat intercepted light of Filling stage was amaximum；intercepted light of blossom stage after filling period．(6) In the farmland shelterbelt the wheat biomass during different stages were obviouslyincreased with distance from forest；the difference of seedling stage was not obvious；wherein，the biomass accumulation from seedling stage to blossom stage was the fastest，andthe differences became evident；the biomass from blossom stage to mature stage accumulatedslowly．The first piont biomass accumulation was always slow，the fourth point biomassaccumulated the most quickly．(7) In the farmland shelterbelt the wheat yield increased with distance of the test pointfrom the forest belt increased，the production of fourth point reached the highest； the first andsecond points wheat yield were in reduction area，the fourth point yield was14．8%higher thanCK． When the crops from the forest a certain distance (2．6H)，appeared increase productionphenomenon． Wheat grain number showed a trend of increase with distance from beltdistance increased，the fourth point reached a maximum value； the thousand grain weight ofwheat showed a trend of increase with distance from belt，the trend was not obvious．(8) In the net of farmland shelterbelt the wheat biomass and light intercepted were closelyrelated，each stage showed strong positive correlation． Among them，in filling stage biomassand light intercepted were most closely related， R2reached0．92； correlation was the worstin seedling stage；wheat yield and the grain number and light intercepted were strong positivecorrelation， R2were respectively0．81and0．78，the correlation of the thousand grain weightof wheat and light intercepted were not obvious．...