摘要
【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。
【Objective】Exploring the effects of conservation tillage and nitrogen application on soil carbon and nitrogen mineralization characteristics,as well as their impact mechanisms on maize photosynthetic characteristics and yield,in order to provide a basis for improving soil fertility and promoting maize production in arid areas of Northwest China.【Method】This study conducted a two-year(2019-2020)maize field location experiment,with traditional tillage(CT)as the control,and set up three protective tillage measures(no tillage:NT;no tillage in wheat season and rotary tillage in maize season:OT;ridge cultivation with no tillage:RNT)and two nitrogen application levels(N0:0;N_(2):170 kg N·hm^(-2)),for a total of 6 treatments.The effects of conservation tillage and nitrogen application on soil nutrient content,carbon and nitrogen mineralization characteristics,maize photosynthetic physiological characteristics,and yield were investigated systematically.【Result】Conservation tillage and nitrogen application significantly increased soil nutrient content(P<0.05).Under N_(2)level,compared with CT treatment,NT,OT,and RNT treatments increased soil organic carbon(SOC),microbial biomass carbon(MBC),total nitrogen(TN),and microbial biomass nitrogen(MBN)content by 8.6%-24.7%,18.9%-27.0%,8.9%-20.2%,and 0.3%-24.9%,respectively.The application of nitrogen significantly increased the accumulation of soil carbon mineralization(Cmin),nitrogen mineralization accumulation(Nmin),and their mineralization rates.Conservation tillage further improved the soil carbon and nitrogen mineralization characteristics.Cmin and Nmin reached their maximum values under RNTN_(2)and OTN_(2)treatments,respectively,which increased by 4.0%-30.2%and 8.0%-52.4%compared with other treatments.Conservation tillage and nitrogen application significantly increased the net photosynthetic rate(Pn),transpiration rate(Tr),and stomatal conductance(Gs)of maize leaves(P<0.05).The Pn,Tr,and Gs of maize reached their maximum values in the OTN_(2)treatment for two years.The yield of maize in two years showed the order of OTN_(2)>RNTN_(2)>NTN_(2)>CTN_(2)>NTN0>CTN0,with the highest yields of 10.52 and 10.91 t·hm^(-2),respectively,which increased by an average of 24.5%and 27.5%compared with other treatments.Based on structural equation modeling analysis,it was found that conservation tillage mainly increased soil nutrient content,promoted soil organic carbon and nitrogen mineralization,enhanced soil available nitrogen supply capacity,and thus promoted the enhancement of maize photosynthetic capacity,achieving maize yield increase.【Conclusion】In the arid northwest region,conservation tillage and nitrogen application were of great significance in promoting soil carbon and nitrogen mineralization,increasing maize yield,and maintaining soil productivity.It was recommended that no tillage in wheat season and rotary tillage in maize season combined with nitrogen application was the optimal management measures for increasing maize yield and efficiency.
作者
卢怡宁
谷晓博
杜娅丹
李晓雁
延廷霖
赵彤彤
LU YiNing;GU XiaoBo;DU YaDan;LI XiaoYan;YAN TingLin;ZHAO TongTong(Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas,Ministry of Education/College of Water Resources and Architectural Engineering,Northwest A&F University,Yangling 712100,Shaanxi)
出处
《中国农业科学》
北大核心
2025年第15期3051-3063,共13页
Scientia Agricultura Sinica
基金
国家自然科学基金(52109066)
中国博士后科学基金(2023T160534)
陕西省博士后科学基金(2023BSHTBZZ29)。
关键词
保护性耕作
施氮
有机碳矿化
有机氮矿化
玉米
产量
conservation tillage
nitrogen application
organic carbon mineralization
organic nitrogen mineralization
maize
yield
