Effcets Of Different Sowing Time On Dry Matter Accumulation And Yield Of Maize-Soybean Intercropping

Sowing date can regulate intercropping groups to light, gas, water, heat and other climate resources utilization of contradiction and competition, improvement of yield components, facilitating crop yield. While two types of crops in intercropping, the choice of crop varieties in interspecific competition at a disadvantage is the key to yield.Therefore, the assurance of the companion crop growth, optimum sowing dates and varieties is important. In Southwest China, rapid development of maize-soybean Strip intercropping, Its cultivation technical system matures, make important contributions to local agricultural production and farmers'income. In recent years, wheat cropping area is less than before, Single asrapeandwheatareahas increased. In this case, press original sowing plantations will reduce corn and soybean yields, In this regard, hoping to find a cultivation technique of strip intercropping of maize-soybean after wheat and rape harvest, seeking a way out for agricultural development in Southwest China. Therefore, the author field experiments studied maize and soybean in different sowing time (maize sowing date:A1:May 15th,A2:May 30th,A3:June 14th;soybean sowing date:Cl:May 30th,C2:June 14th,C3:June 29th), Intercropping of maizeand twovarieties of soybean (B1:Gongxuan No.1, B2:Nandou No.25) To corn and soybean photosynthesis and dry-matter accumulation, grain filling characteristics and yield effects. Results are as follows:1.The net photosynthetic rate of maize early is more than late sowing, crop growth rate higher in early sowing date pre-blooming the early crop growth rate higher than the late sowing 25.9%, after blooming, early sowing date is 9.6% higher than the late one. Early sowing maize grain filling rate is faster than the late sowing, in the drymatterdistributionratioof grain ishigher. Dry matter accumulation per plant after jointing the differences are significant, in mature stage, dry matter accumulation Al is more than A2 and A3, respectively 20.9% and 50.2%. Yields of early sowing date is more than late 88%. Net photosynthetic rate of soybean sowing of corn had no significant effect. But in the reproductive stage, maize dry matter accumulation and grain filling rate was under the influence of soybean sowing, in different varieties of soybean is different. Late-maturing varieties due late seeding (June 14th), early sowing of late-maturing varieties (May 30th),makes the Corn crop growth rate and filling rate are increased, Favour of maizesingleDryMatteraccumulation,increasecornproduction.2.Soybean and maize intercropping, soybean and maize sowing date on soybean's net photosynthetic rate and dry matter accumulation, grain filling rate has a significant impact, with different soybean maturity, its effect is inconsistent.Late maturing soybean and maize intercropping, late sowing of corn make the corn harvestperiods later, symbiosiswithreproductivegrowth of soybean is longer, although in A1, A2, its net photosynthetic rates were not significant, but compared with the A3 sowing their net photosynthetic rate was significantly lower. During peak periods (R4) Al 28.4% higher than the A3. When early sowing of corn, soybean filling rate faster after blooming, crop growth rate higher, the A1 crop growth rate is more than the A2 and A3, respectively 1.8% and 36.1%, its high grain percentage on dry matter distribution, so as to form a higher yield. Early sowing date of soybean, in the vegetative growth phase under the influence of sowing date, the early vegetative stage for too long, appeared overgrowth, late sowing are prematurely enter the reproductive stage, vegetative growth inhibited reproduction and growth. Appropriate late-sown (June 14th) is higher after blooming crop growth rate, the filling rate of late sowing date is higher,heavier grains in maturity, due late sowing date matter accumulation per plant is 23.3% and 43.1% higher than early treatmentandn the late sowing date. Soybean production is higher.Middle-late-maturity soybeans intercropped with maize, Corn should be appropriately late sowing, after soybeans blooming, its higher net photosynthetic rate, and during peak periods (R4) A2 is higher than A1 and A3, respectively 11.1% and 15.7%. It has a higher growth rate,A2 is higher than A1 and A3, respectively 16.4% and 33.2%. More distribution of dry matter in grain Yield increase.. In the late maturing soybean blooming earlier than late maturing soybean, in two late sowing dates of soybean,it is lack of vegetative growth, affecting the reproductive growth and yield. Early sowing date (May 30th), the net photosynthetic rate is higher, Single plant dry matter accumulation increased. Filling rate was higher, the percentage of dry matter distribution in grains is higher, creating high yield.To sum up:to increase corn and soybean production in Corn-Soybean intercropping, choose the early sowing date of corn (May 15th), benefitincreasing the accumulation of dry matter and grain filling, soybean should choose Nandou No.25,15 days sowing soybean after maize, Coordinate the corn and soybean sowing date and soybean varieties, To achieve the purpose of increasing production.