| The objective of this study was to select the optimum tillage pattern to solve the practice problems in Huang-Huai-Hai Plain.Where the plough layer has become shallow resulted by the long-term rotary tillage,and lead to negative effect on crop productivity,such as the plant roots are difficult to grow deeply.Therefore,we designed two field trials:Experiment 1 Plough layer vertical structure capacity expansion:taking 2017 and 2018 wheat seasons as research objects,three treatments were designed and conducted as:(1)rotary tillage-rotary tillage(RT-RT);(2)deep tillage-rotary tillage(DT-RT);(3)deep tillage-light rotary tillage(DT-LRT).Experiment 2 Plough layer horizontal structure capacity expansion:The field experiment was conducted with split plot design as six treatments.Two main treatments with rotary tillage and deep tillage in wheat season,combined with three subsidiary treatments as no-tillage sowing,subsoiling between the row and subsoiling in the row in maize season:(1)rotary tillage+no-tillage sowing(RT-NT);(2)rotary tillage?subsoiling between the rows(RT-SBR);(3)rotary tillage+subsoiling in the rows(RT-SIR);(4)deep tillage+no-tillage sowing(DT-NT);(5)deep tillage+subsoiling between the row(DT-SBR);(6)deep tillage+subsoiling in the rows(DT-SIR).The soil physical,chemical,biological properties and crop yield indexes were measured and analyzed.The main results were as follows:Experiment 1:The capacity of plough layer expansion from vertical direction(1)The soil physical,chemical and biological properties under all treatments were decreased with soil depth in the wheat season of 2017 and 2018.In 2017,the soil bulk density in deep layer was reduced,while the soil porosity was increased under deep tillage treatments.The soil available phosphorus(AP),available potassium(AK),ammonium nitrate(NH4'-N)and nitrate nitrogen(NO3--N)content under RT-RT treatment were significantly higher than that in deep tillage treatment in top soil layer.However,the soil total nitogen(TN),alkali nitrogen(AN),AP,AK,NH4+-N,NO3--N,dissolved organic carbon(DOC)and nitrogen(DON),urease activity,invertase activity,soil microbial biomass carbon(SMBC)and nitrogen(SMBN)was increased under deep tillage treatments in deep soil layer.In 2018,the soil bulk density in 10-30 cm was decreased and the soil porosity in 20-40 cm was increased under DT-RT treatment.The soil bulk density in 10-20 cm was significantly decreased and the soil porosity in 0-40 cm was increased under DT-LRT treatment.The soil nutrient content in deep soil layers was improved under DT-RT and DT-LRT treatments.The AP content in 30-40 cm under DT-RT treatment was increased by 9%compared with RT-RT treatment,with the maximum value 38.1 mg kg-1.The NO3--N content in 20-40 cm under DT-RT treatment was increased by 60%-90%compared with RT-RT treatment.The TN and AN content in 0-20 cm under DT-LRT treatment was the highest one with 1.4 g kg-1 and 94.4 mg kg-1 respectively.The AK in 10—20 cm,soil organic matter(SOM)in 10-30 cm and NH4+-N content in 0—20 cm under DT-LRT treatment was increased by 19%,10%-18%,58%-90%compared with RT-RT treatment.The DON content in 20-40 cm and NO3--N content in 20-40 cm under DT-LRT treatment was increased by 15%and 60%compared with RT-RT treatment,respectively.The urease activity in 20-50 cm under DT-RT treatment was significantly increased by 35%-93%compared to RT-RT treatment.compared with RT-RT treatment,the invertase and phosphatase activity in 10—30 cm was significantly increased by-15%,the SMBN in 10—40 cm significantly increased by 5%-41%,the SMBC in 0-40 cm significantly increase by 7%-25%,under DT-LRT treatment.(2)There was no significant difference among treatments in wheat yield,fertilizer partial productivity and economic benefits in 2017.The number of spikes per ear,kernels per spike,and the 1000-grain weight,and wheat yield under DT-LRT treatment were increased in 2018 compared with that in 2017.The fertilizer partial productivity and economic benefit under DT-LRT was significantly higher than that under RT-RT treatment in 2018.In sum,under the deep tillage-light rotary tillage treatment,the soil bulk density was decreased,soil nutrient content,soil biological activity,and yield were increased.It was suggested that the deep tillage-light rotary tillage was suitable for Fluvo-aquic soilExperiment 2:The capacity of plough layer expansion from horizontal direction(1)The soil physical,chemical and biological properties under all treatments were decreased with soil depth in the wheat season and maize seasonThe SOM content in 20-40 cm,the AN,AP.AK content in 0—50 cm and the NH4+-N and NO3--N content in 40—50 cm under all treatments were incrsased in maize season compared with that in wheat season.In wheat season,the soil bulk density was reduced,while the soil porosity was increased under deep tillage(i.e.DT-NT,DT-SBR and DT-SIR)treatments.The TN,AN,AP and NH4+-N content under rotary tillage treatments(i.e.RT-NT,RT-SBR and RT-SIR)were significantly higher than that in deep tillage treatments(i.e.DT-NT,DT-SBR and DT-SIR)in top soil layer.However,the SOM,TN,AN,AP,NH4+-N,and NO3--N content in 30-40 cm,SMBC and SMBN in 20-40 cm and the urease,invertase and phosphatase activity in 20—40 cm under deep tillage treatments(i.e.DT-NT,DT-SBR and DT-SIR)were increased in deep soil layer.In maize season,the soil bulk density in 10—30 cm was decreased and the soil porosity in 0—50 cm under DT-SIR treatment was increased.The SOM content in 0—30 cm under DT-NT treatment was increased by 40.1%-64.3%compared with RT-NT treatment.The TN content in 0—30 cm under RT-SBR and RT-SIR treatment was increased,with the maximum value as 1.4 g kg-1.The AN content in 0-20 cm under RT-SBR treatment was increased by 15.0%-25.3%compared with RT-NT treatment,with the maximum value as 38.1 mg kg-1.The NH4+-N and NO3--N content in 20—50 cm under DT-SIR treatment was increased compared with RT-RT treatment,with the maximum value as 30.4 mg kg-1 and 8.9 mg kg-1.The DOC content in 20—40 cm and DON content in 0—30 cm under RT-SBR treatment was increased.The SMBC in 20-40 cm and SMBN in 0—20 cm under DT-SIR treatment was increased.The urease and invertase activity in 0—40 cm under RT-SBR treatment was significantly increased,with the maximum value as 2.80[NH3-N mg(g·24h)-1],1.83[Glu.m g(g·24h)-1],respectivly.The phosphatase activity in 10—40 cm and 20—40 cm under RT-SBR treatment was higher than that under the other treatments.(2)In maize season,the ear length,100-grain weight,harvest index and yield under DT-SBR and DT-SIR were significantly higher than that under the others.The yield under DT-SBR and DT-SIR was increased by 6.4%-10.8%compared with that under RT-NT treatment.The fertilizer partial productivity and economic benefit under DT-SIR treatment was highest in maize season.In sum,the soil physical,chemical,biological properties and crop yield were improved under the DT-SIR treatment,and it was suggested as the optimum practice in this study. |
PDF Full Text Request