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Gansu Agricultural University (2010)

Effects Of Conservation Tillage On Soil Ecology And Crops Physiological Characteristics Of Wheat-Isatis Rotation In Arid Area

Yang Jiang Shan

Titre : Effects Of Conservation Tillage On Soil Ecology And Crops Physiological Characteristics Of Wheat-Isatis Rotation In Arid Area

Auteur : Yang Jiang Shan

Grade : Doctoral Dissertation 2010

Université : Gansu Agricultural University

Résumé partiel
Less rainfall is the important limiting factor of agriculture development in semi-arid regions on the Western Loess Plateau. Traditional agriculture measure led to declined soil quality, serious soil erosion, low field capacity and productivity in the region. Many studies showed that conservation tillage ,such as no-tillage, stubble cover, and stubble standing could increase soil water holding capacity, fertility and infiltration, water use efficiency and productivity, it could also reduce soil erosion.This study was finacially supported by 2006BAD15B06 project, and carried out from 2007 to 2008 year in Semi-arid Loess Plateau of Gansu Dingxi. Three treatments, traditional tillage (T), no-tillage (NT) and no-tillage with straw mulch (NTS) were involved in W→I and I→W rotations experiment. Effects of conservation tillage on soil physical and biological characteristics, crop physiological and biochemical characteristics, photosynthetic characteristics and yield were studied to explore the mechanism of increasing water use efficiency and improving production under appropriated conservation tillage. Main results showed that:1.Conservation tillage could decrease soil bulk density, increase soil porosity and saturated hydraulic conductivity. In W→I and I→W rotations under T, NT and NTS different tillage methods,soil bulk density showed NTS NT>T too. Soil saturated hydraulic conductivity were NTS>NT>T in two rotation, and showed significant difference between treatments. In comparison, conservation tillage improved soil quality better in I→W rotation.2.NTS could improve soil temperature in cool season, and decrease soil temperature in hot season, this could help crops emergence and roots growth. At sowing and seedling stage of wheat and Isatis, soil temperature in different depths showed NTS> NT>T. Soil average temperature of NTS was increased by 2.33℃than that of T at 0-15cm layer in wheat sowing. At wheat seedling stage, soil average temperature of NTS was increased by 3.00℃than T. At Isatis sowing, soil average temperature of NTS was increase by 2℃than T in 0-15cm depth. In hot season,wheat field average temperature was reduced by 2.71℃than T in 0-15cm soil depth,and that of Isatis of NTS was reduced by 1.96℃than T. Wheat field was better at soil temperature adjusting than Isatis field under different tillage methods.3. NTS could increase soil water content of plough layer significantly in W→I and I→W rotations. During wheat and Isatis growing period, average soil moisture of two rotations in 0-30cm,30-200cm and 0-200cm all indicated NTS>T>NT. In 0-30cm depth,during wheat growing period,soil average water moisture of NTS was increased by 6.67% and 6.64% than NT and T respectively in W→I rotation,and In I→W rotation,soil average water content of NTS was increased by 5.81% and 3.36% than NT and T. In growth period of Isatis, Isatis average soil water content of NTS was increased by 3.87% and 3.16% than NT and T in W→I rotation,and In I→W rotation, wheat field average water content of NTS was increased by 5.46% and 4.79% than NT and T. Comparing two rotations, soil water content in W→I was higher during Isatis growing period, but that of I→W was higher during wheat growing period.4. Conservation tillage could significant improve soil enzyme activities and soil microorganisms quantity in W→I rotation. In Isatis field and wheat field, soil urease, alkaline phosphatase and invertase hydrolase activitise showed NTS>NT>T in same soil depth. In 0-30cm soil depth, all soil average hydrolase and oxidoreductase activities were NTS>NT>T, NTS had the significant effect to increase enzyme activities. Compared with W→I, I→W increased soil hydrolase and oxidoreductase activities better. From T, NT to NTS, quantity of soil microorganisms were increased gradually in W→I and I→W rotations at different layer. All soil bacteria, fungi, actinomycetes and total microbes were NTS> NT> T in 0-30cm depth.

Mots clés : conservation tillage, wheat-Isatis rotation, soil quality, crop physiological characteristics, photosynthesis, yield, water use efficiency

Présentation (Dissertationtopic )

Page publiée le 21 avril 2013, mise à jour le 4 mai 2018