| Weibei highland of Shaanxi province belongs to warm temperate and semi-humid prone todrought climate zone, and drought is the biggest limiting factor in crop production on dryland.Shortage of precipitation and uneven distributions in seasons are the main factors to cause thelow and unstable yields of winter wheat and spring maize growth on dryland. In order to studythe effects of soil water conservation, yield and benefit increasing of different rotational tillagepatterns in winter wheat-spring maize rotation field in Weibei highland, a field experiments ofNT/ST (no-tillage in the first year, subsoiling in the second year, again no-tillage followed byalternating the next year), ST/CT (subsoiling in the first year, conventional tillage in the secondyear, again subsoiling followed by alternating the next year) and CT/NT (conventional tillage inthe first year, no-tillage in the second year, again conventional tillage followed by alternating thenext year) rotational tillage,and conventional tillage(CT/CT), continuous subsoiling (ST/ST)andcontinuous no-tillage(NT/NT) treatments were conducted under different fertilizing (balancedfertilization, conventional fertilization, and low fertilizer treatment) levels during2007—2013inHeyang, Shaanxi. Soil physical structure and stability, soil moisture, soil nutrients, also wheatand maize agronomic traits and yield response were studied. The main results are as follows:1. Effects of different tillage patterns on soil bulk density, soil porosity, field water capacityand aggregate stabilityCompared with CT/CT, three rotational tillage patterns significantly decreased soil bulkdensity, enhanced soil total porosity, field water capacity and soil organic matter. In harvestingtime, average soil bulk density under NT/ST treatment was3.2%lower than CT/CT treatmentand average soil total porosity, field water capacity and soil organic matter was3.0%,10.0%and9.9%higher than CT/CT treatment. Soil aggregates properties changed significantly under threedifferent rotational tillage treatments, NT/NT, ST/ST and NT/ST was higher in themacro-aggregate content (R0.25) and stability rate of water stable aggregate and mechanicalstable aggregate than CT/CT treatments at0～60cm; NT/ST was also higher in water stableaggregate of water-stable aggregates than CT/CT at t0～60cm, average water stable aggregateunder NT/ST treatment was26.9%higher than CT/CT theatment. 2. Effects of different tillage patterns on soil moisture characteristicsIn fallow period, average water conservation rate under NT/ST, ST/CT and CT/NT treatmentwas22.4percentage points,4.4percentage points and4.9percentage points higher than CT/CTtreatment, respectively. Average soil water storage in0～200mm soil layer under NT/STandCT/NT treatment was18.2mm and11.8mm higher than CT/CT treatment. In wheat growthperiod, average soil water storage in0～200mm soil layer under NT/ST and CT/NT treatmentwas13.2mm and14.6mm higher than CT/CT treatment. In maize growth period, average soilwater storage in0～200mm soil layer under NT/ST and CT/NT treatment was16.2mm and11.7mm higher than CT/CT treatment, respectively, it had no significant differences amongST/CT treatments and CT/CT treatments.3. Effects of different tillage patterns on soil fertilityCompared with Low fertility, Balance fertility significantly increased soil organic matter andNPK content. Compared with CT/CT, NT/ST, CT/NT and ST/ST were conducive to theaccumulation of soil organic matter, average soil organic matter under NT/ST treatment was11.5%higher than CT/CT theatment.4. Effects of different tillage patterns on agronomic traits of wheat and maizeNT/ST and ST/ST treatment showed a higher stem number than CT/CT treatment, averagestem number under NT/ST treatment was13.8%higher than CT/CT treatment. Compared withCT/CT, NT/ST treatment significantly decreased plant height and dry biomass of winter wheatand spring maize. Soil moisture under NT/ST treatment was better, so its leaf area andphotosynthetic characteristics were better than ST/CT and CT/NT treatments, dry matteraccumulation and stomatal conductance were better than CT/CT and ST/CT treatments.5. Effects of different tillage patterns on crop yield and water use efficiency of wheat andmaizeCompared with Low fertility, Balance fertility and conventional fertility significantlyincreased spike number and1000-kernel weight of winter wheat and spring maize; In winterwheat production year, average yield of wheat under NT/ST and ST/CT treatment was increased8.1%and8.9%compared to CT/CT separately, and water use efficiency of wheat was increased14.3%and13.8%respectively. In spring maize production year, average yield of maize underNT/ST and ST/CT treatment was increased9.8%and4.9%compared to CT/CT separately, andwater use efficiency of maize was increased6.5%and6.1%respectively, and average yield andwater use efficiency of maize under CT/NT treatment was close to CT/CT treatment.6. Effects of different tillage patterns on economic benefits of crop productionCompared with low fertility treatment, balance fertility and conventional fertility treatmentsignificantly increased crop net income.Compared with CT/CT, NT/ST and CT/NT treatments reduced tillage mechanical inputs, increased the yield in drought years, so it improved economicbenefit. Net income of winter wheat and spring maize of NT/ST treatment was increased1340yuan/hm2and2426yuan/hm2compared to CT/CT.In conclusion, the effects of water storage capacity, soil fertility, soil physical structureimproving and crop yield increasing under balance fertility and NT/ST treatment, it was the bestone among three rotational tillage patterns, so balance fertility and NT/ST is a more appropriatefertilization and rotational tillage pattern for the wheat-maize rotation field in Weibei highland. |
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