| Soil water is the main factor affecting crop production in arid regions.The direct source of soil water is rainfall,thus the full use of natural precipitation is important of crop production.Tillage significantly affects soil moisture.Conservative tillage techniques such as reduce tillage with no fertilization(NT),subsoiling tillage(ST),combined with surface straw residue cover,it can effectively increase the infiltration rate of precipitation,and reduce the ineffective evapotranspiration of soil moisture,increase the use of natural precipitation.In crop production in arid regions,planting density is a key factor affecting soil water use.Planting density insufficient and the surface is bare,which increases the ineffective evapotranspiration of soil moisture.planting density excessive can cause excessive loss of soil moisture,which is not conducive to sustainable water use and will also directly affect the crop production,and irrational nitrogen application is also a key factor affecting crop yield and water use.And tillage,nitrogen application and density have a synergistic effect on crop production and interrelated.Therefore,we set up a comparative trial of tillage,nitrogen application and density comprehensive experiment in Weibei dryland in 2017.Three tillage methods were set:Conventional tillage with crop residue buried(CT),no tillage with crop residue covered(NT)and subsoiling tillage with crop residue covered(ST).And three nitrogen application rates:nitrogen-free(Z);medium nitrogen(M):N:150 kg/hm~2;high nitrogen(H):N:225 kg/hm~2;phosphate fertilizer applied uniformly:120kg/hm~2;potash fertilizer:75kg/hm~2.Two planting densities:D1:52500plants/hm~2;D2:67500plants/hm~2.Combining tillage,density and nitrogen application,a total of 18 kinds of corn comprehensive cultivation patterns and repeated 2 times for a total of 36 test area.The water,nutrients,agronomic traits and yield effects of different cultivation modes were studied and the following research progresses were made in the experiment:Effects of different cultivation mode on soil moisture of maize fields.During the fallow period,conservation tillage with straw mulching can significantly improve soil water storage,NT showed best in soil water storage,followed by ST then CT.Compared with CT,soil water storage at the end of fallow period of NT and ST increased by 23.4mm and12.2mm.The water conservation rate increased by 37.2%and 17.4%,and the average soil water evaporation rate increased by 70%and 32.4%.It can be seen that conservation tillage technology can better adapt to the rainfall characteristics in the area.In the growth period,under the same tillage,the water use efficiency increased with the increase of density and nitrogen application rate.The average soil water storage during the growth period of CT treatment decreased with the increase of the density.The NT and ST are just the opposite,soil water storage at D2 density was 0.7%and 3.5%higher than that of D1.Under the same tillage,the average soil water storage during the growth period decreased with the increase of nitrogen application rate.The average soil water storage under Z nitrogen fertilizer treatment was 1.7%and 2%higher than that of M nitrogen fertilizer.Effects of different cultivation mode on nutrient in maize field at harvesting stage.Compared with different tillage treatments,ST can effectively increase soil nutrient content.The contents of soil TN,TP,AP,AK,and organic matter under ST treatment were 5%and3.7%,2.7%and 1.8,4.4%and 2.7%,18.4%and 10.3%,10.8%and 4.2%higher than CT and NT,Planting density has no significant effect on soil TN content.But the average soil TP content at the D1 density was 4.1%higher than D2 density,while the average soil AP,AK,and organic matter content at the D2 density were 1.7%,26.4%,and 1.4%higher than D1 density.Compared with different nitrogen treatments,under the same tillage,the soil TN and organic matter content increased with the increase of nitrogen application amount.The average soil TN and organic matter content of M fertilizer treatment was 9.9%and 8.9%higher than Z treatment.TP,AP,and Ak are just the opposite,the content of TP,AP,and AK in soil treated with Z fertilizer was 2.8%,4.0%,and 9.7%higher than that of M fertilizer,but there was no significant difference in the treatment of M fertilizer and H fertilizer.Effects of different cultivation mode on agronomic characters of spring maize.The plant height and stem diameter under NT and ST treatment increased by 5%and8.2%,12.7%and 16.7%compared with CT,indicating that ST was more conducive the growth of spring maize.The plant height,stem diameter,LAI(leaf area index)and DMA(dry matter accumulation)of spring maize under NT and ST treatments all increased with increasing density.Comparing different nitrogen application rates,plant height,stem diameter and LAI showed a trend with an increase first and then decreases with increasing nitrogen application rate.The plant height,stem diameter and LAI of M fertilizer treatment increased by 17.1cm,0.23mm and 14.3%compared with Z fertilizer treatment.The DMA of all treatments increased with the increase of nitrogen application rate.The DMA under M fertilizer treatment was 19.6%higher than that of Z fertilizer treatment.There was no significant difference between M fertilizer and H fertilizer.Effects of different cultivation mode on yield and economic benefit of spring maize.ST can effectively increase the yield of spring maize.The average yield under ST treatment is 3372 kg/hm~2.Compared with CT and NT,the yield increase was 27.8%and 15.3%.In the same tillage mode,the yield increased with increasing density and nitrogen application rates.The average increase rate of D2 density was 29.2%higher than D1.And the average increase rate of M nitrogen fertilizer treatment was 30.7%higher than Z nitrogen fertilizer treatment.Analyze the net income.The average net income under ST treatment is 212yuan/hm~2.Compared with CT and NT,it increased by 1498 yuan/hm~2 and 826 yuan/hm~2.The average net income under D2 density is higher than D1 density by 438 yuan/hm~2.And the average net income of M nitrogen fertilizer treatment is increased by 1075 yuan/hm~2compared with Z nitrogen fertilizer,but there is no significant difference between M nitrogen fertilizer and H fertilizer.Overall,the comprehensive cultivation patterns of ST,M nitrogen fertilizer(N150kg/hm~2)and D2 density(67500 plants/hm~2)can improve soil moisture in dryland corn fields,promote crop growth,improve soil fertility and fertilizer use efficiency,maintaining high yields and economic levels is the advantageous comprehensive cultivation model for dryland corn production. |
PDF Full Text Request