| This study selected a6-year continuous spring maize expirenment field on Weibeihighland,through integration of fertilization and cultivation measures, which includedreduction of nitrogen fertilizer,soil tillage and straw mulching, to strengthen management ofrainfall and soil water during the fallow period and annual regulation of soil water andnutrient, and to explore its effects on crop yield, water use efficiency, soil moisture changeand its balance on spring corn field of weibei dryland. Through combination treatments ofdifferent fertilization practices (balanced fertilization, conventional fertilization, low fertilizertreatment) and different conservation tillage (continuous no tillage(NT-NT), continuoussubsoiling(ST-ST),continuous plowing(CT-CT), subsoiling and no tillage rotation(ST-NT),no tillage and plowing rotation(NT-CT), subsoiling tillage plowing rotation(ST-CT))),toinvestigate its effects on soil physical and chemical characteristics,soil water conservation,water use efficiency, maize growth and yield and economic returns. Results and progress ofthe study are as followings:(1) Effects of different rotational tillage on soil bulk density,soil porosity, soil waterholding capacity and soil aggregate stability of maize fieldWith soil depth got deeper, soil bulk density increased. Effects of fertilizationtreatments on the bulk density and soil porosity did not reach significant level. under samefertilization treatment, compared with continuous conventional tillage (CT-CT), soil bulkdensity increased and soil porosity increased under continuous no tillage (NT-NT)treatment, soil bulk density decreased and soil porosity increased under rotational tillagetreatment (NT-ST, NT-CT, CT-ST). Under balanced fertilization treatment, soil field waterholding capacity and aggregate stability were improved, with no significant differencesamong different tillage treatments. Under same fertilization treatment, compared withconventional tillage (CT-CT), water capacity and soil aggregate stability of conservationtillage treatments were improved in different extent.(2) Effects of different rotation tillage on soil water retention and crop water useefficiency Compared with conventional tillage of continuous ploughing (CT-CT) treatment, underthe same fertilization level treatment, soil water storage capacity in0—200cm soil layer ofspring maize field under conservation tillage during winter fallow were improved, and soilwater storage capacity in0—200cm soil layers under continuous no tillage treatment,subsoiling and no tillage rotation treatment was increased19.72%and13.42%(P<0.05)respectively. Compared with continuous plowing, soil water storage of0-200cm soil layersunder conservation tillage treatment during maize growth period increased in varying extent,its value of subsoiling and no tillage rotaion treatment, continuous no tillage treatment wereincreased9.69and2.11mm respectively, and soil water content increased20.08%and4.38%respectively, its fallow efficiency were increased by0.65and0.46percent. Averagewater use efficiency in6years of no tillage and subsoiling rotation treatment, continuous notillage treatments than conventional tillage were increased18.59%,5.82%,separately.(3) Effects of conservation tillage and its rotation on soil nutrientsWith soil depth increasing, total nutrient and available nutrient content were reduced.At the same level of fertilization, compared to traditional tillage of continuous plowing(CT-CT), continuous no tillage (NT-NT) and rotation tillage treatment (NT-ST, NT-CT,CT-ST,0-20cm) significantly increased the soil organic matter, total nitrogen and availablenitrogen content. Total and available phosphorus, potassium content under different rotationtillage were no significant difference to continuous plowing.(4) Effects of conservation tillage and its rotation on agronomic traits of spring maizeAt the same level of fertilization, compared to traditional tillage of continuous plowing(CT-CT), plant height and dry matter accumulation under continuous no tillage (NT-NT)treatment and rotation tillage treatments (NT-ST, NT-CT, CT-ST) in different growth stageof spring maize were increased. Under same tillage treatment, plant height and dry matteraccumulation of balanced fertilization treatment and traditional fertilization treatmentduring spring maize growth period were higher than low fertilizer treatment.(5) Effects of conservation tillage and its rotation on crop yield of spring maizeAt the same level of fertilization, compared to traditional tillage of continuous plowingtreatment (CT-CT), crop yield of spring maize under conservation tillage treatmentincreased. average grain yield in6years of spring maize under subsoiling and no tillagerotation treatment and continuous no tillage treatment increased7.64%and0.34%respectively, and harvest index were increased by3.64and2.28percentage points,increment of crop yield and harvest index of no tillage and subsoiling rotation treatmentwere the most obvious one. Under the same tillage treatments, maize yield and harvest index of balanced fertilizer treatment were highest, maizr yield and harvest index of lowfertilizer treatment and conventional fertilizer treatment were not significant.In conclusion, conservation tillage improved soil structure, and soil aggregate contentand stability increased, soil water storage abilityin0-200cm soil layers increased, and cropwater and nutrient use efficiency were improved, so it were beneficial to increase springmaize yield and were suitable fallow management measuers for spring maize production inWeibei plateau. |
PDF Full Text Request