The Effect Of Field Arrangement To The Population Structure And Yield Of Corn In Mid-high Density

In this study, we adopt the randomized block design and use compact maize variety Zhenghong6as the experimental materials. The density is set at two levels, which are45000plants·hm-2(A1)and67500plants-hm"2(A2), and the filed arrangement are set at100cm(B1),150cm+50cm(B2),80cm(B3),110cm+50cm(B4) and60cm(B5), respectively. We are aimed to found out the best filed arrangement of the canopy structure, field microclimate characteristic, dry matter accumulation and yield components for maize at different density level. The main results are summarized as follows:1. The value of the leaf area per plant and the leaf width decreases while the LAI value and the leaf length increases under the high density A2condition. In the density of A1, the largest leaf area per plant appears in the60cm row spacing, compared to the density of Al, the largest leaf area per plant appears in the80cm row spacing in the density of A2. The leaf area per plant and the leaf width adopt the equal row spacing is greater than that adopt corresponding wide-narrow row in both densities, we indicate that the width of the leaf is the main reason for the difference of leaf area in different densities and row spacing forms. Angle between leaf and stem in both densities performs that the wide-row spacing has the largest angle and follow by the corresponding equal row and narrow row, which is opposite to the pattern of LOV. The results indicate that the leaves of the corn will be more upright when the row spacing is smaller, and to some degree, the decrease of row spacing will weaken the impact of light transmittance between lines.2. The average daily temperature of the ear layer in the density of A2and the average spacing of80cm shows:in narrow rows>in wide rows>in equal rows, which is contrast to other disposal. The average daily humidity of the ear layer in the density of Al shows:in wide rows>in narrow rows>in equal row, in the wide-narrow rows>in the equal rows. In the density of A2and the average spacing of100cm the average daily humidity shows:in narrow rows>in wide rows>in equal rows, in the wide-narrow rows>in the equal rows, while the average row spacing of80cm performs oppositely. The average daily wind speed of the canopy and the average daily wind speed of the ear layer performs differently in different densities and row spacing forms, and in a day, the difference of the wind speed of the canopy is less than that of the ear layer in each density and row spacing form.The average daily soil heat flux in each treatment shows:in equal rows>in narrow rows,but it is different at different times of a day. The PAR transmittance in the density of A1is greater than that in the density of A2; In both densities, the average PAR transmittance performs: in wide rows>in corresponding equal rows>in narrow rows, and it decreases with the average row spacing decrease. Extinction coefficient in the density of A1is smaller than that in the density of A2, in narrow rows>in corresponding equal rows>in wide rows.3. Under the high density condition, the dry matter accumulation per plant decreases, while the dry matter accumulation of all groups increases, and the dry matter allocating to the ear reduces. In the density of A1, the dry matter accumulation in equal row spacing forms is higher than that in wide-narrow rows, and it is the highest in the row spacing form of60cm. In the density of A2, both the dry matter accumulation and the dry matter allocating to the Ear are the highest in filed arrangement of110cm+50cm.4. The effects of the planting density and filed arrangement on the yield of maize reach a very significant level and significant level. Under the condition of high density, the results indicate that ear length, kernels per row, ear rows and grain weight per plant all show a decreasing trend, only barren ear tip length and effective panicle become smaller, in this case, the average yield in A2is still more than that in A1by21.71%. In the density of Al, the highest yield which reached to6876.45kg·hm-2appears in the filed arrangement of B5, and the yield in the equal row spacing is higher than that in the wide-narrow row spacing. In the density of A2, the highest yield reaching to8065.2kg·hm-2appears in the filed arrangement of B4. With the average spacing decreases, ear length, grains/row, grains/ear, as well as increased, while changes in grain weight per plant show reverse.Totally, these results suggest that the high yield is mainly due to the high density, and a reasonable spacing form can effectively improve the field microclimate in high density condition, such as the light, the temperature and the ventilation condition, which would make the individual fully developed and lay the foundation for the further increase of the production. In summary, this study indicate that the density of67500plants/hm-2and the wide-narrow rows110cm+50cm is the best configuration fit for zhenghong6.