Soil Physicochemical Characteristics And Maize Productivity As Influenced By Straw Retention

The field trials were conducted for consecutive three years(2016 to 2018)at the Agricultural Science and Technology demonstration fields,Mengcheng County,Anhui province,Peoples' Republic of China.The study focused crop residue management impacts on the structure of the soil and subsequent effects on soil hydrodynamic performance and maize productivity.Six treatments comprised of wheat(W)and maize(M)straw returning to field and fertilizer(F)application were formed which included T1=W1M1F1,T2=W1M0F1,T3=W0M1F1,T4=W0M0F1,T5=W1M1F0 and T6=W0M0F0.1.The results revealed that effects of crop residue retention treatments on soil hydrodynamic performance(soil N concentration,available P/K,SOM),physiological traits(biomass yield,LAI,chlorophyll content)and agronomic parameters(Plant height,seedling height,1000-grain weight,grain yield ha-1)were significant(P<0.05).The trend of soil hydrodynamic,physiological and agronomic performance due to years(2016-2018)did not show greater variability.2.The soil N content before sowing was observed to be inversely proportional to soil depth;while soil N was higher under straw retention treatments,maximized in Ti at all soil depths.This variation in soil N is justifiable,because site had already been in use for similar studies.In case of P,with increasing soil depth,the available P was considerably decreased;but increase was manifold under maize-wheat straw retention plus fertilization.The soil available K was higher in residue retention treatments over control.Similarly,surface soil contained higher SOM and due to crop residue retention and fertilization,the soil organic matter was improved.3.After harvest of 3rd year test crop(maize),at surface soil,N content in Ti increased upto 88.95%,upto 84.97%at 10-20 cm,upto 75.78%at 20-30 cm and at 30-40 upto 83.80%cm over control(T6).Soil available N,P and K were significantly increased(P<0.05)in crop residue retention treatments and in surface soil,the soil N content in T5,T4,T3,T2 and T1 was increased by 11.79,23.58,36.59,35.37 and 60.98%,available P increased by 37.75,118.98,127.88,155.16 and 202.47%and available K increased by 14.29,21.97,42.99,59.64 and 68.21%over control(T6).4.The trend of treatment effectiveness on biomass yield during three years of experiment varied significantly and the upper limit of increase in biomass yield in Ti.In this treatment,at jointing,big flare,flowering,grain formation and harvesting stages the biomass yield in 2016 was increased by 68.21,570.6,344.5,302.3 and 231.8%;in 2017 biomass increased by 3183.4,3122.7,824,1035.9 and 802.3%;and in 2018 biomass yield increased by 335.9,570.6 344.5,302.3,231.8%,respectively over control(T6).Similarly,the leaf chlorophyll content(SPAD)was lowest at Jointing and highest at anthesis stage.The leaf chlorophyll content improved successively with the crop residue retention treatments across crop stages and reached to highest at anthesis stage,and later declined at mid grain filling stage.However,there was exceptional improvement under the combined effect of wheat and maize straw retention treatments plus fertilization;however,wheat plus fertilization was more effective to improve leaf chlorophyll content than maize straw plus fertilization.A significant increase in LAI(P<0.05)at all growth stages in all the residue retention treatments,and highest values were recorded in Ti and least in control(T6).The trend of LAI in all three years of experiment showed similarity.In 2018 LAI improved maximum in T1()at jointing(2002.03%),at big flare(425.36%),at anthesis(207.09%),at mid grain filling(461.90%)and at maturity the increase was 890.32 percent over control(T6).5.The treatment effect on agronomic performance of maize showed that increase in plant height due to crop residue retention treatments during 2016 in T5,T4,T3,T2 and T1 was 12.28,35.59,44.54,51.67 and 58.79 percent,in 2017 increased by 4.86,18.71,25.54,30.76 and 37.23%;while in 2018 it was 5.85,19.69,26.53,31.75 and 38.21 percent,respectively over control(T6).Likewise,seedling height in T5,T4,T3,T2 and T1 during 2016 increased by 38.89,130.56,144.44,166.67 and 179.86%,in 2017 increased by 28.24,90.59,100.03,110.59 and 122.35%;while in 2018 it was 28.22,90.59,100.02,110.60 and 122.33 percent,respectively over control(T6).In 2016 increase in T5,T4,T3,T2 and T1 was 6.87,15.84,16.73,17.88 and 18.67 percent,in 2017 it was 14.54,24.94,25.67,27.13 and 28.16 percent;while increase in 2018 was 6.87,15.84,16.73,17.88 and 18.66 percent,respectively over control(T6).Similarly,in 2016,increase in grains cob-1 in T5,T4,T3,T2 and T1 was 59.27,164.42,189.69,212.19 and 228.33 percent;in 2017 it was 57.28,116.17,135.17,156.98 and 170.39 percent;while increase in 2018 was 57.28,116.17,135.17,156.98 and 170.39 percent,respectively over control.So far the grain yield of maize is concerned,in 2016 increase in the grain yield ha-1 in T5,T4,T3,T2 and T1 was 42.62,85.21,95.24,108.75 and 119.78 percent;in 2017 it was 49.30,308.51,329.98,358.78 and 381.61 percent;while increase in yield during 2018 was 42.62,85.21,95.24,108.75 and 119.75 percent,respectively over control.The treatments based on crop residue retention plus fertilization showed exceptionally promising performance by increasing grain yield more than double,particularly in T1 and T2,where wheat/maize straw retention plus fertilization was practiced.It is suggestible that for achieving higher grain yields in maize,wheat and maize straw both may be retained in addition to fertilization;because under this treatment the crop residues worked as compost and improved SOM that resulted in improved soil fertility.