Effect of soil surface roughness on emergence rate and yield of mechanized direct-seeded rapeseed based on 3D laser scanning

The quality of seedbed after sowing such as soil surface roughness is one of the key factors affecting the seedling emergence of rapeseed,which ultimately affected crop yield.However,the effect of soil surface roughness on seedling emergence and yield of rapeseed is still unclear.In this study,field experiments at the experimental site of Jianli and Shayang were carried out.Three treatments were designed:relative slow(M1),medium(M2),and fast(M3)forward speed of the unit.Soil surface roughness measured by a 3D laser scanner,seed quantity of the seeder,emergence rate and yield of rapeseed were determined to investigate the soil surface roughness effect on emergence rate and yield of rapeseed.The results showed that as the forward speed of the unit increased,the compartment surface became rougher.Compared with the M1 and M2 treatments,soil surface roughness under the M3 treatment increased by 36.5%and 9.8%,respectively.The actual seed quantity of the seeder under different treatments ranged from 3806.56 to 4158.18 g/hm2.The average error rate of the actual and theoretical seed quantity was less than 5%,which met the operational quality requirements for seeding rapeseed crops.As the forward speed of the unit increased,the actual seed quantity of the seeder gradually increased while the emergence rate and yield of rapeseed decreased.The seed quantity under the M3 treatment increased by 6.9%and 4.7%,while the emergence rate of rapeseed decreased by 3.3%and 2.0%,and the yield decreased by 23.2%and 13.1%,compared with the M1 and M2 treatments,respectively.Correlation analysis indicated that emergence rate and yield of rapeseed were negatively influenced by soil surface roughness.Considering rapeseed emergence rate,seed yield,and economic benefits,the M1 treatment was recommended.But considering the factor that the M1 treatment may reduce the unit operation efficiency,and thus resulting in lower cost of production,M2 could be recommended in actual farming.The results of this study laid a theoretical foundation for analyzing the relationship between the seedbed surface quality and seedling emergence and yield.

Biomimetic earthworm dynamic soil looser for improving soybean emergence rate in cold and arid regions

In cold and arid regions,soil moisture content and accumulated temperature were seriously insufficient during spring sowing,which made it difficult for soybean seedling to emerge.Based on the principle of earthworm optimization and improvement of soil structure,this study innovatively designed a biomimetic earthworm dynamic soil looser through bionic design and theoretical calculation.By highly reducing the movement path and mode of earthworm in the soil,the mechanism could improve the soil temperature(ST)and soil moisture content(SMC),and thus greatly improve the soybean emergence rate(SER).In this study,the effects of biomimetic earthworm dynamic soil looser and its design parameters on soil temperature(ST),soil moisture content(SMC)and soybean emergence rate(SER)were investigated by two-factor test,analysis of variance(ANOVA)and Least significant Difference(LSD).Regression analysis was used to establish the mathematical model between design parameters and soybean emergence rate.MATLAB software was used to optimize the model,and the optimal design parameter combination was obtained.The contrast experiments showed that the biomimetic earthworm dynamic soil looser could construct the soil structure more suitable for the cold and arid regions.Compared with rotary blade(RB)and notched disc harrow(DH),biomimetic earthworm dynamic soil looser could increase soil moisture content by 41.30%and 27.50%,respectively.Compared with the notched disc harrow,the soil temperature could be increased by 7.97%.There was no significant difference between the effect of rotary blade on soil temperature(p>0.05).The soybean emergence rate was increased by 25.40%and 20.70%,respectively,compared with that of notched disc harrow and rotary blade.

Cutting Propagation Technique of Pennisetum purpureum Schum

[Objectives]The paper was to study the cutting propagation technique of Pennisetum purpureum Schum and to provide a technical reference for establishing an efficient cutting propagation method.[Methods]Six treatments were set up using P.purpureum cv.Guiminyin and P.purpureum cv.Guimu-1 as test materials,including 1-node oblique insertion,1-node oblique insertion+rooting powder,1-node transverse burial,2-node oblique insertion,2-node oblique insertion+rooting powder and 2-node transverse burial.The following indices were observed and determined for P.purpureum cuttings:emergence rate,rooting rate,root number,longest root length,fresh root weight,plant height,number of tillers,number of leaves,and fresh stem and leaf weight.[Results]In the 2-node cutting+rooting powder treatment,Guiminyin and Guimu-1 exhibited the highest survival rate,root growth indices,and stem and leaf growth indices,with the emergence rates of 94.29%and 90.26%,respectively.The 2-node cutting treatment followed closely behind,while the 1-node cutting treatment had the lowest indices.Under the same treatment,Guimuyin exhibited higher mean values for plant height,number of leaves,fresh stem and leaf weight,longest root length,and fresh root weight compared to Guimu-1.However,it had lower mean number of tillers,and emergence rate and rooting rate of the 1-node cutting treatment compared to Guimu-1.[Conclusions]The P.purpureum cuttings thrived in the 2-node cutting+rooting powder treatment,and the overall cutting effect of Guiminyin was superior to that of Guimu-1.