Effects Of Conservation Tillages And Its Rotations On Spring Maize Field Of Weibei Highland

To deal with the status quo of rain scarcity and over-high evaporation on Weibei Highland and explore the proper measurements of conservation tillage and rotation tillage as to achieve the goals of increasing soil water conservation, gaining soil fertility, grain yield and income on spring maize field of Weibei Highland, during2007-2011, a series of study were conducted:The effect of soil water conservation,variation of physicochemical characteristics, efficiency of water up-taking, maize agronomic traits and comparison of revenues during winter fallow under different fertilizing (balanced fertilization, conventional fertilization, and low fertilizer treatment) levels, conservation tillage and rotation tillage combinations. The primary research results are as below:1.Impactons of conservation tillage and crop rotation measures on soil physical properties, and water conservationUnder different levels of fertility, the soil bulk density increased with soil depth under all tillage treatments; Under three types of tillage techniques, the values of soil bulk density ranked as no-tillage treatment> sub-soiling treatment> deep plowing treatment. With the successive implementation of conservation tillage, no-tillage and sub-soiling treatments showed to increase the content of the soil aggregates significantly. The average soil water content and soil water storage under no-tillage and deep plowing treatments were significantly higher than them under conventional tillage treatments.Under different levels of fertility, the no-tillage and sub-soiling shifting combination was the most effective measure to reduce the bulk density of top soil and improve soil structure. After four fallow periods results indicated that no-tillage and sub-soiling were significantly effective in water conservation; the average soil water content and average storage capacity were16.2%and441.5mm under no-tillage-deep plowing shifting treatment; continuous deep plowing was the lowest, respectively,15.7%and405.5mm.In2010and2011, two years of spring maize growth periods, under balanced fertilizing and sub-soiling treatment, the largest value of0～300cm soil layer water storage capacity was up to406.3mm whilst in2008to2011, four years of spring maize growth periods and under no-tillage-sub-soiling shifting cultivation, it was407.2mm.2.Conservation tillage and rotation tillage on soil nutrientsDuring2010to2011, under different treatments and fertility levels,0～60cm layer of soil available nutrient content showed the same fluctuation trend, total nutrients and available nutrient contents decreased with the going down of soil depth. Under different fertility levels, deep plowing and no-tillage treatments in0～60cm showed the higher average total and available soil nutrient content compared with sub-plowing treatment. Under the different levels of fertility, no-tillage-sub-soiling shifting treatment aided to increase available soil nutrients and organic matter formation.3. The impactions of conservation tillage and crop rotation on agronomic traits of spring maizeUnder different tillage practices, the spring maize plant height and dry matter accumulation of balanced fertilization and conventional fertilization treatment were significantly higher than of the low-fertilizer treatment; in the same fertility level, the spring maize plant height and dry matter accumulation of sub-soiling and no-tillage treatments compared with deep-plowing treatment were higher. Under different levels of fertility, no-tillage-sub-soiling shifting treatment can be conducive to root growth and dry matter accumulation of spring maize.4. conservation tillage and crop rotation on water use efficiencyBy2010-20112-year experimental study, the results showed that:the highest average water use efficiency was balanced fertilization and sub-soiling combination of spring maize,20.9kg/(hm2·mm) in2years, followed by conventional fertilization sub-soiling for19.3kg/(hm2.mm), low fertilizaion-sub-soiling treatment worst,16.1kg/(hm2·mm).Under different fertility levels by2008-20114-year plot study, from2008to2010and2008to2011the average water use efficiency of no-tillage-sub-soiling shifting treatment was the highest, of20.5kg/(hm2·mm). Under different combinations of tillage rotation from2008to2010and2008to2011, balanced fertilization average water use efficiency was up to:20.1kg/(hm2·mm).5. Effect of conservation tillage and tillage rotation on spring maize yield and revenueBy2010-20112-year plot study, the balanced fertilization and sub-soiling combination of spring maize showed the highest average yield and average net income, respectively,9098.7kg·hm-2, and6972.9yuan/ha, then followed by conventional fertilization and sub-soiling combination of8270.3kg·hm-2, and6491.4yuan/ha, and the low fertilization and deep plowing combination showed the lowest:6895.5kg·hm-2and4224.7yuan/ha.By the2008-20114-year plot study, under different fertility levels, no-tillage-sub- soiling shifting treatment showed the highest average yield and average net income, re spectively8452.1kg·hm-2and7604.4yuan/ha.Therefore,the balanced fertilization and no-tillage-sub-soiling treatment combination is the best combination mode in Weibei high land in improving spring maize yield and water use efficiency.