| The Hexi Region is a typical agricultural production area in China.The terrain is relatively flat,the sunshine duration is long,and the temperature varies greatly from day to day.It is convenient for crop irrigation,and provides good conditions for the growth and development of crops.However,the shortage of water resources,extensive irrigation management and the need to optimize the planting pattern in this area seriously restrict the sustainable development of local agriculture.In this study,spring maize(Qiangsheng No.51)under plastic film drip irrigation in the Hexi Region was used as the research object.Field experiments were carried out at the Shiyang River Basin Agricultural and Ecological Water-saving Experimental Station of China Agricultural University from April to September 2020.There were two irrigation amounts(W1:80%ET_c,W2:100%ET_c,where ET_c is crop evapotranspiration),two planting densities(D1:80000 plants/hm~2,D2:100000plants/hm~2)and three row spacings(L1:equal row spacing)40 cm+40 cm,L2:equal spacing 60 cm+60 cm,L3:wide and narrow rows 80 cm+40 cm).By measuring the plant height,stem diameter,leaf area index(LAI),chlorophyll content(SPAD),light energy interception rate,yield and composition factors,crop water consumption,plant nitrogen absorption and other indicators of spring maize,the research on irrigation amount,planting Effects of density and row spacing on the growth,physiology,yield and water and fertilizer use efficiency of spring maize to determine the appropriate irrigation amount and planting pattern for spring maize under mulched drip irrigation in the Hexi Region.The results of the study are as follows:(1)Planting density and row spacing had extremely significant effects on plant height and stem diameter of spring maize(P<0.01).The interaction of irrigation amount,planting density and row spacing had significant effects on plant height and stem diameter of spring maize at different growth stages(P<0.05).The maximum values were obtained in W1D2L2and W2D1L3,respectively.LAI showed the trend of rapid growth at first,then steady growth and finally decrease,and planting density and row spacing had extremely significant effects on leaf area index(P<0.01).There were significant differences in dry matter accumulation between different row spacings,and the overall pattern was wide and narrow rows of 80 cm+40 cm>equal row spacing 60 cm+60 cm>equal row spacing 40 cm+40cm,and the W2D2L3 treatment obtained the largest value of 96.45 t/hm~2.(2)The average SPAD value of spring maize at different growth stages(tasseling stage,grain filling stage,maturity stage)showed the same trend:W2>W1,D2<D1,80 cm+40cm wide and narrow row>60 cm+60 cm equal spacing>equal spacing 40 cm+40 cm.Under the same irrigation amount,increasing the planting density significantly decreased the SPAD value of leaves,and the photosynthetic rate of the panicle leaves was significantly lower under the D2 treatment than the D1 treatment.All showed a trend of L3>L2>L1.With the advancement of the growth period,the light transmittance of spring maize canopy showed a trend of first decreasing and then increasing,and the light energy interception rate in D2 treatment was higher than that in D1 treatment.Under the same planting density,the light transmittance of spring maize showed the law of L3>L2>L1,which was consistent with the change law of photosynthetic rate,and the light energy utilization rate reached the maximum in D2L3 treatment.(3)Under the same irrigation conditions,the cumulative nitrogen uptake of D2treatment was significantly higher than that of D1,and the cumulative nitrogen uptake of wide and narrow rows was significantly higher than that of equal row spacing,and the maximum value was obtained in W2D2L3.Different organs of spring maize have different nutrient utilization efficiency.From jointing stage to mature stage,the proportion of stem and leaf in total nitrogen uptake decreases gradually,nutrients are transferred to grain,and the proportion of grain nutrient in total increases gradually.The overall situation of soil nitrogen residues showed a trend of decreasing soil nutrients with the increase of soil depth.The proportion of nutrient in the 0-20 cm soil to the total amount was basically larger than that in the other layers,and the nitrogen accumulation in the 40-60 cm soil in the W2treatment was higher than that in the W1 treatment.Compared with D1,the planting density of D2 was lower than that of D1,but the whole filling duration was prolonged,and the filling process of L2 and L3 treatments was significantly longer than that of L1 treatment.(4)The interaction between planting density and row spacing configuration had a significant effect on yield and its components(P<0.05).The highest yield of W2D2L3 was17.72 t/hm~2,but it was not significantly different from that of W1D2L3,and the water content of W1D2L3 was not significant.The water use efficiency(WUE)was largest at 3.57kg/m~3.The harvest index and fertilizer partial productivity(FPF)under the D2 treatment were significantly higher than those in the D1 treatment(P<0.05),and the harvest index and fertilizer partial productivity(FPF)under the wide and narrow row treatment were significantly higher than those in the equal row spacing treatment(P<0.05).The interaction of crop quantity,planting density and row spacing configuration had a significant effect on harvest index and PFP(P<0.05),and the interaction of the three had a very significant effect on crop water consumption(ET)and WUE(P<0.01).To sum up,the irrigation amount,planting density and row spacing have certain regulatory effects on the growth,population structure,water consumption,grain weight and water and fertilizer use efficiency of spring maize under drip irrigation in Hexi area,and the overall performance is planting density>row spacing>Irrigation volume.Comprehensive analysis,the combination of 80%ET_c+100,000 plants/hm~2+80 cm+40 cm wide and narrow row width and narrow row is the suitable irrigation amount and planting mode for drip irrigated spring maize(Qiangsheng 51)in the Hexi Region. |
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