Tillage practice and residue management play important roles in N pool in soils. This study determined the impacts of tillage practice and residue management on crop yield. It also investigated the distribution, fractionation, and stratification of N at soil at depths ranging from 0 to 60?cm under wheat–maize cropping systems. Three treatments were established in 2009: no-tillage with straw removal for winter wheat and summer maize (NT), no-tillage with straw mulching for winter wheat and summer maize (NTS), no-tillage with straw mulching for summer maize and plow tillage with straw incorporation for winter wheat (NPTS). After 8 years, soil total nitrogen (TN) content in NTS was greater than in NT, but only in 0–10?cm layer. NPTS treatment increased TN content over NT and NTS in 10–20?cm layer by 18.0% and 13.9%, and by 16.8% and 18.1% in 20–30?cm layer, respectively. Particulate organic N, microbial biomass N and water-extractable organic N levels were the greatest in 0–10?cm layer under NTS treatment; and in 10–30?cm layer, the corresponding values were the highest under NPTS treatment. NPTS treatment could immobilize the mineral N in 10–30?cm layer, and reduced leaching losses into deeper soil layers (40–60?cm). Furthermore, total yield increased by 14.7% and 8.5% in NPTS treatment compared to NT and NTS treatments, respectively. These results indicate that NPTS is an effective and sustainable management practice, which will improve soil fertility, sustainable crop production, and environmental quality in low-productivity soils in central China. 農(nóng)耕措施和秸稈處理對土壤氮素管理有重要影響。本研究測定了不同農(nóng)耕措施和秸稈處理下小麥-玉米種植系統(tǒng)中 0-60 cm深度土層中氮的分布、形態(tài)分析和分層情況,并探討了對作物產(chǎn)量的影響。實驗于 2009 年進行,設(shè)置了三種處理:冬小麥-夏玉米免耕無秸稈(NT)、冬小麥-夏玉米免耕秸稈覆蓋 (NTS)、冬小麥-夏玉米免耕秸稈還田(NPTS)。8年后測定相關(guān)數(shù)據(jù),NTS處理土壤全氮 (TN)含量僅在0-10 cm土層大于NT處理;相較于NT處理和NTS處理,NPTS處理使10-20 cm土層中的TN含量分別增加了18.0% 和13.9%,20-30 cm土層中的TN含量分別增加了16.8% 和18.1%。在NTS處理下,0-10cm土層中有機氮、微生物生物量氮和水可提取有機態(tài)氮含量最高;在10-30 cm土層中則是NPTS處理下最高。NPTS處理中,礦物氮被固定在10-30cm的土層中,并更少地浸出損失到更深的土層(40-60 cm)。此外,與NT和NTS處理相比,NPTS處理中作物總產(chǎn)量分別增加了14.7% 和 8.5%。這些結(jié)果表明,NPTS是一種有效和可持續(xù)的管理措施,能夠改善中國中部低生產(chǎn)力土壤的肥力狀況,實現(xiàn)可持續(xù)的作物生產(chǎn)和環(huán)境質(zhì)量保障。 |
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來自: 昵稱37581541 > 《秸稈還田》