秸秆还田年限与钾肥互作对春玉米冠层生理及产量的影响OA

To investigate the effects of the duration of straw return and the interaction with potassium fertilizer on the physiological characteristics of the maize canopy and yield,plots were established in fields where straw had been re-moved,and in fields where straw had been continuously returned for 6 and 10 years.Within each plot,five potassium ap-plication rates were set at 0,45,90,135,180 kg/hm2,respectively.Maize leaf area index(LAI),light-availability density(LAD),soil and plant analysis development(SPAD values),photosynthetic rate(Pn),and yield were measured.The re-sults showed that the physiological parameters of the spring maize canopy-LAI,LAD,SPAD,chlorophyll density,and in-dividual plant photosynthetic capacity-exhibited an increasing trend with the duration of straw return,following the order:10-year of straw return＞6-year of straw return＞straw removal;Under different potassium application treatments,all physiological indicators for the no-stubble treatment increased with increasing potassium application rates.For the 6-year and 10-year straw return treatments,physiological indicators initially increased and then decreased with increasing potassium application rates,reaching their peaks at 135 and 90 kg/hm2,respectively;Overall grain yield followed the or-der:10-year straw return＞6-year straw return＞straw removal.Under the same straw return duration but different potassium treatments,the highest yields were observed in the straw removal treatments with 180 kg/hm2,6-year straw return with 135 kg/hm2,and 10-year straw return with 90 kg/hm2.In summary,continuous straw return allows for re-duced potassium fertilizer application while maintaining high canopy physiological activity and increasing maize yield.