Effects Of Alternate Years Deep Plowing On Soil Fertility, Groth And Grain Yield In Summer Maize

The experiments were carried out on the farm of Henan University of Science andTechnology from October2009to October2011. This test adopted the six kinds ofprocessing methods as follows：two years conventional tillage and no-straw amendedtreatments, alternate years deep plowing and no-straw amended treatments, two yearsdeep plowing and no-straw amended treatments, two years conventional tillage andstraw amended treatments, alternate years deep plowing and straw amended treatments,two years deep plowing and straw amended treatments. The effects of six treatmentson the soil physical properties、soil chemical properties、soil enzyme activity、summermaize growth and yield were studied by field experiments and laboratory analysis. Themain conclusions were as follows:1. Effects of alternate years deep plowing on soil bulk density and watercontentSoil bulk density in deep plowing was less than conventional tillage. The resultsshowed that, comparing with conventional tillage, soil bulk density in deep plowingseparately decreased0.085g/m3and0.06g/m3in seeding period and maturation period.In addition, soil bulk density in straw amended treatments was less than no-strawamended treatments under the different straw treatments. Comparing with no-strawamended treatments, soil bulk density in straw amended treatments separatelydecreased0.210g/m3and0.15g/m3in seeding period and maturation period.The changes of soil water content with different tillage methods in each growingstage as follows: Soil water content of all the soil layers in straw amended treatmentswere higher than no-straw amended treatments in each growing stage. At0-20cm soillayer, Soil water content in deep plowing were higher than conventional tillage in eachgrowing stage. After that, soil water content in conventional tillage was rapidly fallingwith the increase of soil depth. On the contrary, soil water content in deep plowingdecreased slowly or appeared to be rising. There were no significant differences in soil water content between alternate years deep plowing and two years deep plowing.2. Effects of alternate years deep plowing on soil fertilitySoil organic matter content in alternate years deep plowing and two years deepplowing were higher than two years conventional tillage with the same straw treatment.At0-10cm soil layer, Soil organic matter content in alternate years deep plowing andstraw amended treatments was highest and more than6%comparing with two yearsconventional tillage and no-straw amended treatments. At10-20cm soil layer, Soilorganic matter content in two years deep plowing and straw amended treatments washighest and more than10.45%comparing with two years conventional tillage andno-straw amended treatments. At20-40cm soil layer, Soil organic matter content inalternate years deep plowing and straw amended treatments was more than7.92%comparing with two years conventional tillage and no-straw amended treatments. Itwas thus clear that deep plowing and straw amended treatments could significantlyimprove soil organic matter content of all the soil layers. Meanwhile, there were nosignificant differences in alternate years deep plowing and two years deep plowing.Soil alkali-hydrolyzable nitrogen、soil available phosphorus and soil availablepotassium of the different treatments decreased with the soil depth. The availablenutrients content in deep plowing was significantly higher than conventional tillage,and the available nutrients content in straw amended treatments was also higher thanno-straw amended treatments. But there were no significant difference on threeavailable nutrients between alternate years deep plowing and two years deep plowing.3. Effects of alternate years deep plowing on soil enzymeIn summer maize maturation period, straw amended treatments couldsignificantly improve the activity of catalase, urease, alkaline phosphatase and sucroseamong different soil layers(0-10，10-20，20-40cm). Straw treatments were nosignificant difference on soil enzyme in alternate years deep plowing and two yearsdeep plowing. Alternate years deep plowing and two years deep plowing couldsignificantly improve soil enzyme activity and soil nutrient content of all the soil layerwith the same straw treatments, and there was no significant difference between thetwo cultivation methods. It could performance the superiority of alternate years deepplowing.4. Effects of alternate years deep plowing on aging characteristics of earleaves after flowering and maize yieldStraw amended treatments and alternate years deep plowing led to significantly increase the SOD and POD activities of corn leaves in each growth period and theMDA content remain comfortably low. All these made leaf physiological functionstronger in later growing period. Compared to conventional tillage, alternate yearsdeep plowing could significantly increase the leaf-area-index in each growth period.Deep plowing and straw amended treatments led to the ultimate yield respectivelyincreased15.56%and2.83%on average compared with conventional treatment andno-straw amended treatments. Therefore, deep plowing and straw amended treatmentshad an important role in increasing yield. However, there was no significant differenceon increasing yield between alternate years deep plowing and two years deep plowingunder the same of Straw treatments.