Effects Of Expanding Line Spacing And Shrinking Row Spacing On The Canopy Structures And Dry Mater Accumulation And Transportation Of Spring Corn

In order to reveal the physiological and ecological mechanisms of increasing the planting density and yield under the pattern of expanding line spacing and shrinking row spacing,at the experimental farm of Inner Mongolia University for the Nationalities from 2015 to 2016,with 101 NH and 702 WK as tested varieties,conventional planting pattern of local farmers as control,under 6×104 plants·hm-2(D1)and 7.5×104 plants·hm-2(D2)and 9×104 plants·hm-2(D3)planting density,the effects of expanding line spacing and shrinking row spacing on spring corn canopy structures features and physiological property and dry matter production and yields were studied.The main test results are as follows:1.The leaf area index of spring corn in each treatment at the late growth stage was higher than that of CK and the decline rate is slower than that of CK under the pattern of expanding line spacing and shrinking row spacing,in which the variance was the most obvious of milking in D2.The angle between stem and leaf is smaller and leaf orientation value is larger of top leaves under the pattern of expanding line spacing and shrinking row spacing,the angle between stem and leaf is larger and leaf orientation value is smaller of middle and lower leaves under the pattern of expanding line spacing and shrinking row spacing.Canopy transmittance rate of silking and milking each layers was higher than that of CK under the pattern of expanding line spacing and shrinking row spacing,in which the variance was the most obvious in ear layer of milking under D2.2.The net photosynthetic rate of spring maize each treatment was higher than that of CK in silking and milking under the pattern of expanding line spacing and shrinking row spacing,in which the variance was larger in lower leaves of milking under D3.The leaf area duration of population in each layer was also higher than that of CK after silking under the pattern of expanding line spacing and shrinking row spacing,in which the variance was the most obvious in D2.The SPAD and NDVI value of leaf each growth stage were higher than that of CK under the pattern of expanding line spacing and shrinking row spacing,and the difference of milking and maturity reached significant level,in which the variance was the most obvious in D2.The SOD and POD of leaf enzyme activity each layer at silking and milking were higher than that of CK,MDA content was less than that of CK under the pattern of expanding line spacing and shrinking row spacing.3.The dry matter accumulation and rate of spring corn each treatment were lower than that of CK before silking under the pattern of expanding line spacing and shrinking row spacing,and were significantly higher than that of CK at all growth stages after silking,in which the variance was the most obvious of silking-milking growth stage in D2.The dry matter translocation and rate of stalk was significantly higher than that of CK and the leaves were significantly lower than CK under the pattern of expanding line spacing and shrinking row spacing.The contribution rate of dry matter translocation to grain that stalk was significantly higher than that of CK and leaves were significantly lower than that of CK in the density of D2 and D3 under the pattern of expanding line spacing and shrinking row spacing.The dry matter distribution ratio in each organs of spring corn stalk and leaves were lower than that of CK,but spike and grain were higher than that of CK in maturity under the pattern of line spacing expansion and row spacing shrinkage.4.There was no significant difference between expanding line spacing and shrinking row spacing and CK in effective spike number of spring maize each treatment.The grain number per spike was higher than that of CK under of the pattern expanding line spacing and shrinking row spacing and most of which reached significant level.The 1000-kernel weight was the same as grain number per spike,and the difference was significant only under the D2 of 101 NH in 2015.5.The actual yields of spring corn in each treatment were significantly higher than CK under the pattern of expanding line spacing and shrinking row spacing and the highest yield under D2,and the actual yields of 101 NH reached 15.18 t?hm-2 in 2015 and 13.98 t?hm-2 in 2016,and the actual yields of 702 WK reached 14.80 t?hm-2 in 2015 and 13.84 t?hm-2 in 2016.