ObjectivesThis study aimed to compare the effects of long-term different tillage and mulching methods on physical and chemical properties of surface soil, and the consequent agronomic characters of maize, to provide the references for choosing suitable tillage and mulching method in tableland region of the Loess Plateau.
MethodsThe long-term field trials are composed of 12 treatments: conventional tillage (CT), CT + film mulching, CT + straw mulching, CT + side-film mulching, CT+ whole film mulching, CT + straw and film mulching, tillage every other year (OT), no-tillage (NT), NT + film mulching, NT + straw mulching, NT + grass mulching, NT + straw and film mulching. The soil physical and chemical properties and the agronomic characters of maize after 12 years' consistent treatment were investigated.
ResultsThe no-tillage treatment reduced the soil bulk density and temperature during seedling emergence, reduced soil total P and available P content in mature stage, improved the saturated hydraulic conductivity and surface soil moisture from April 28 to October 15, the plant height, leaf area index and yields of maize were decreased as a result. Film mulching was able to reduce diurnal temperature, increase soil bulk density very significantly (P < 0.01), decrease saturated hydraulic conductivity significantly (P < 0.05) and decrease organic matter and total N of soil in maize mature stage. All the treatments containing film mulching increased the height, the yield and leaf area index of the maize very significantly (P < 0.01). Straw mulching showed different effects on ρb and Ks, they increased soil bulk density under conventional tillage but decreased it under no-tillage slightly; Compared with the no-straw-mulching treatments, straw mulching led very significant improvement of plant growth and yield (P < 0.01), as they could reduce the surface temperature, increase organic matter and total N of soil significantly (P < 0.05).
ConclusionsNo-tillage without mulching is capable of improving soil physical properties, but not of keeping soil moisture necessary for maize growth, so it is not acceptable for high yield maize production. No-tillage combined with straw and film mulching could significantly increase maize yield as they are effective in increasing soil organic matter and total N content. All types of film mulching have significant yield increase effect, of them, combined straw and film mulching is proved to be the optimal one in tableland region of the Loess Plateau.
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