An approach to green manure crop rotation fallow technigues for rainfed farmland in semi-arid areas
To explore the methods of reasonable management and protection of fallow land,the cultivated land in semi-arid ecological degradation area was used as the research object,three years of field experiments were carried out,including five treatments:Vicia villosa → rape → V.sativa(R1),rape → V.sativa → V.villosa(R2),V.sativa → V.villosa → rape(R3),abandoned(control 1)and leisure(control 2),the soil moisture and nutrients in farmland under different treatment conditions were monitored systematically to clarify the impact of different tillage measures,green manure varieties,and rotation sequences on soil quality in fallow farmland.The results showed that,more than 2257.5-3478.3kg·hm-2 dry matter biomass was produced and returned to the soil under green manure rotation treatments,although the average annual soil moisture dissipation in farmland increased by 17.69-71.36mm compared to control,respectively,also organic matter content was increased significantly by 8.87-32.8％compared to control 1 and control 2.The total dry matter of green manure returning to soil in R3 treatment during one rotation cycle was increased by 54％and 19.9％compared to R1 and R2 treatments respectively,the total dissipation of soil moisture in farmland was 62.98mm,29.14mm,140.34mm,and 202.78mm higher than that of R1,R2,control 1,and control 2,the water production efficien-cy increased by 39.3％and 21.4％compared to R1 and R2 treatments.The soil bulk density of 0-40cm has no significant difference between different treatments,which was between 1.151-1.219g·cm-3.The organic matter content in the 0-20cm soil layer in R3 increased by 27.5％,2.6％,44.5％,and 18.4％compared to R1,R2,control 1,and control 2,respectively.On the whole,the restoration of arable land quality is slow under traditional abandonment and leisure methods,reasonable rotation of green manure crops can accelerate the restoration of farmland quality effectively,Vicia sativa→ Vicia villosa→Rape is the best rotation sequence for green manure returning to field,which can be promoted and applied in semi-arid ecological degraded areas.
fallowtillage measuresgreen manurerotationsoil moisturephysical and chemical properties
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