【目的】探究保护性耕作和施氮对土壤碳氮矿化特性及其对玉米光合特性和产量的影响机理,为提高西北旱区土壤肥力、促进玉米生产提供依据。【方法】通过两年(2019—2020年)玉米田间定位试验,以传统耕作(CT)为对照,设置3种保护性耕作措施...【目的】探究保护性耕作和施氮对土壤碳氮矿化特性及其对玉米光合特性和产量的影响机理,为提高西北旱区土壤肥力、促进玉米生产提供依据。【方法】通过两年(2019—2020年)玉米田间定位试验,以传统耕作(CT)为对照,设置3种保护性耕作措施(免耕:NT;小麦季免耕玉米季旋耕:OT;起垄免耕:RNT)和2个施氮水平(N0:0;N_(2):170 kg N·hm^(-2)),共6个处理。系统研究保护性耕作和施氮对土壤养分含量、碳氮矿化特性、玉米光合生理特征和产量的影响。【结果】保护性耕作和施氮显著提高了土壤养分含量(P<0.05),N_(2)水平下NT、OT和RNT处理土壤有机碳(SOC)、微生物量碳(MBC)、全氮(TN)和微生物量氮(MBN)含量较CT分别提高了8.6%—24.7%、18.9%—27.0%、8.9%—20.2%和0.3%—24.9%。施氮显著增加了土壤碳矿化累积量(Cmin)、氮矿化累积量(Nmin)及其矿化速率,保护性耕作进一步提高了土壤碳、氮矿化特性。Cmin和Nmin分别在RNTN_(2)和OTN_(2)处理下达到最大值,较其他处理分别提高了4.0%—30.2%和8.0%—52.4%。保护性耕作和施氮显著提高了玉米叶片净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)(P<0.05),两年玉米Pn、Tr和Gs均在OTN_(2)处理达到最大值。两年玉米产量均表现为OTN_(2)>RNTN_(2)>NTN_(2)>CTN_(2)>NTN0>CTN0处理,最高产量分别为10.52和10.91 t·hm^(-2),较其他处理分别平均提高了24.5%和27.5%。基于结构方程模型分析发现,保护性耕作主要通过增加土壤养分含量,促进了土壤有机碳氮矿化,提升了土壤有效氮供应能力,进而促进玉米光合能力增强,实现玉米增产。【结论】在西北旱区,保护性耕作和施氮对于促进土壤碳氮矿化、提升玉米产量和维持土壤生产力具有重要意义,推荐小麦季免耕玉米季旋耕结合施氮为玉米增产提效最优管理措施。展开更多
Film mulching system is a widely employed agricultural practice worldwide. However, the effects of different planting and mulching patterns on soil nutrient content and enzymatic activity have not been well documented...Film mulching system is a widely employed agricultural practice worldwide. However, the effects of different planting and mulching patterns on soil nutrient content and enzymatic activity have not been well documented. In this study, we examined the impact of four planting and mulching patterns（including control, flat planting without mulching; M1, flat planting with film mulching; M2, ridge-furrow planting with film mulching on both ridges and furrows; and M3, ridge-furrow planting with film mulching on continuous ridges） on the seed yield of winter oilseed rape, soil moisture, soil temperature, soil organic carbon（SOC） content, soil nutrient content, and soil enzymatic activity over three growing seasons from 2012 to 2015 in a winter oilseed rape field in the semi-arid area of Northwest China. Seed yield of winter oilseed rape, soil moisture, soil temperature, enzymatic activities, and contents of nitrate-nitrogen, available phosphorus, and available potassium were all significantly higher in mulching treatments（M1, M2 and M3） than in control treatment over the three growing seasons, whereas SOC content was significantly lower in mulching treatments than in control treatment during 2013–2014 and 2014–2015. Among the three mulching treatments（M1, M2 and M3）, the M3 treatment showed consistently higher seed yield, SOC content, nutrient contents, and enzymatic activities than the other two treatments. Seed yield of winter oilseed rape was 41.1% and 15.0% higher in M3 than in M1 and M2, respectively. SOC content and soil enzymatic activities in the top 0–20 cm soil layers and nitrate-nitrogen content in the top 0–30 cm soil layers were all significantly higher in M3 than in M1 and M2. Therefore, we advise the ridge-furrow planting with film mulching on continuous ridges（i.e., M3） as an efficient planting and mulching pattern for sustainably improving the seed yield of winter oilseed rape and preserving soil fertility in the semi-arid area of Northwest China.展开更多
文摘【目的】探究保护性耕作和施氮对土壤碳氮矿化特性及其对玉米光合特性和产量的影响机理,为提高西北旱区土壤肥力、促进玉米生产提供依据。【方法】通过两年(2019—2020年)玉米田间定位试验,以传统耕作(CT)为对照,设置3种保护性耕作措施(免耕:NT;小麦季免耕玉米季旋耕:OT;起垄免耕:RNT)和2个施氮水平(N0:0;N_(2):170 kg N·hm^(-2)),共6个处理。系统研究保护性耕作和施氮对土壤养分含量、碳氮矿化特性、玉米光合生理特征和产量的影响。【结果】保护性耕作和施氮显著提高了土壤养分含量(P<0.05),N_(2)水平下NT、OT和RNT处理土壤有机碳(SOC)、微生物量碳(MBC)、全氮(TN)和微生物量氮(MBN)含量较CT分别提高了8.6%—24.7%、18.9%—27.0%、8.9%—20.2%和0.3%—24.9%。施氮显著增加了土壤碳矿化累积量(Cmin)、氮矿化累积量(Nmin)及其矿化速率,保护性耕作进一步提高了土壤碳、氮矿化特性。Cmin和Nmin分别在RNTN_(2)和OTN_(2)处理下达到最大值,较其他处理分别提高了4.0%—30.2%和8.0%—52.4%。保护性耕作和施氮显著提高了玉米叶片净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)(P<0.05),两年玉米Pn、Tr和Gs均在OTN_(2)处理达到最大值。两年玉米产量均表现为OTN_(2)>RNTN_(2)>NTN_(2)>CTN_(2)>NTN0>CTN0处理,最高产量分别为10.52和10.91 t·hm^(-2),较其他处理分别平均提高了24.5%和27.5%。基于结构方程模型分析发现,保护性耕作主要通过增加土壤养分含量,促进了土壤有机碳氮矿化,提升了土壤有效氮供应能力,进而促进玉米光合能力增强,实现玉米增产。【结论】在西北旱区,保护性耕作和施氮对于促进土壤碳氮矿化、提升玉米产量和维持土壤生产力具有重要意义,推荐小麦季免耕玉米季旋耕结合施氮为玉米增产提效最优管理措施。
基金supported by the Special Fund for Agro-scientific Research in the Public Interest,China (201503125,201503105)the National High Technology Research and Development Program of China (2011AA100504)
文摘Film mulching system is a widely employed agricultural practice worldwide. However, the effects of different planting and mulching patterns on soil nutrient content and enzymatic activity have not been well documented. In this study, we examined the impact of four planting and mulching patterns（including control, flat planting without mulching; M1, flat planting with film mulching; M2, ridge-furrow planting with film mulching on both ridges and furrows; and M3, ridge-furrow planting with film mulching on continuous ridges） on the seed yield of winter oilseed rape, soil moisture, soil temperature, soil organic carbon（SOC） content, soil nutrient content, and soil enzymatic activity over three growing seasons from 2012 to 2015 in a winter oilseed rape field in the semi-arid area of Northwest China. Seed yield of winter oilseed rape, soil moisture, soil temperature, enzymatic activities, and contents of nitrate-nitrogen, available phosphorus, and available potassium were all significantly higher in mulching treatments（M1, M2 and M3） than in control treatment over the three growing seasons, whereas SOC content was significantly lower in mulching treatments than in control treatment during 2013–2014 and 2014–2015. Among the three mulching treatments（M1, M2 and M3）, the M3 treatment showed consistently higher seed yield, SOC content, nutrient contents, and enzymatic activities than the other two treatments. Seed yield of winter oilseed rape was 41.1% and 15.0% higher in M3 than in M1 and M2, respectively. SOC content and soil enzymatic activities in the top 0–20 cm soil layers and nitrate-nitrogen content in the top 0–30 cm soil layers were all significantly higher in M3 than in M1 and M2. Therefore, we advise the ridge-furrow planting with film mulching on continuous ridges（i.e., M3） as an efficient planting and mulching pattern for sustainably improving the seed yield of winter oilseed rape and preserving soil fertility in the semi-arid area of Northwest China.
