秸秆还田下氮肥水平对秸秆碳固定及土壤有机碳储量的影响  

Effects of nitrogen fertilizer level on straw carbon sequestration and soil organic carbon stock under straw returning

作　　者：孙旭超 张紫薇 王若飞 冯成 曹凑贵[3] 王浩 杨青华[1] 张学林[1] 胡权义 SUN Xuchao;ZHANG Ziwei;WANG Ruofei;FENG Cheng;CAO Cougui;WANG Hao;YANG Qinghua;ZHANG Xuelin;HU Quanyi(Agronomy College,Henan Agricultural University,Zhengzhou 450046,China;Yexian Agricultural Production Accident Appraisal Service Center,Yexian 467200,China;College of Plant Science and Technology,Huazhong Agricultural University,Wuhan 430070,China)

机构地区：[1]河南农业大学农学院,郑州450046 [2]叶县农业生产事故鉴定事务中心,叶县467200 [3]华中农业大学植物科学技术学院,武汉430070

出　　处：《中国生态农业学报（中英文）》2024年第9期1556-1565,共10页Chinese Journal of Eco-Agriculture

基　　金：国家自然科学基金项目(31670447)资助。

摘　　要：土壤有机碳(SOC)库在养分循环和缓解全球温室效应方面起重要作用。为了探究氮肥对秸秆碳在土壤中的转化以及SOC库的影响,本研究采用盆栽试验,向不同施氮水平[0 kg(N)∙hm^(-2)(N0)、120 kg(N)∙hm^(-2)(N120)、240 kg(N)∙hm^(-2)(N240)、360 kg(N)∙hm^(-2)(N360)]的稻田土壤中添加^(13)C标记的小麦秸秆,在水稻成熟后采集土样测定不同碳组分含量以及δ^(13)C值,并分析土壤微生物群落组成。研究结果显示,与N0处理相比,N240和N360处理中SOC显著提高7.8%和7.4%,全氮显著提高37.2%和34.3%,溶解性有机碳显著提高33.7%和48.6%,微生物量碳显著提高97.9%和89.6%;但土壤碳氮比显著降低21.6%和20.0%。相比N0处理,N120处理的SOC、全氮、碳氮比和溶解性有机碳并没有显著差异,但显著提高微生物量碳的含量。此外,秸秆还田条件下施用氮肥使细菌含量显著提高24.7%~55.4%,真菌含量显著提高18.3%~30.2%,总磷脂脂肪酸含量显著提高18.1%~45.2%。施用氮肥提高>2000μm和250~2000μm团聚体的占比以及游离态颗粒有机碳(fPOC)和微团聚内颗粒有机碳(iPOC)组分的有机碳储量,同时分别显著增加了fPOC和iPOC组分中δ^(13)C值128.3%~194.8%和105.6%~216.9%。但是在高氮(N360)处理下,除fPOC组分外,其他各有机碳组分储量未持续增加。结构方程表明,施用氮肥可通过增加溶解性有机碳含量,增加土壤中fPOC组分中有机碳储量,或者促进微生物群落活性增加iPOC组分中有机碳储量来提高SOC含量。本研究结果表明,秸秆还田条件下施用适量氮肥能够促进秸秆碳在土壤中的固定并且增加SOC含量。Soil organic carbon(SOC)plays a crucial role in nutrient cycling and mitigating global greenhouse gas effects.This study aimed to assess the influence of nitrogen fertilizer on straw carbon dynamics in soil and its implications for SOC accumulation.A pot experiment was conducted using paddy soil with wheat straw returning subjected to varying nitrogen application levels[0,120,240,360 kg(N)∙hm^(-2)],denoted as N0,N120,N240,and N360,respectively.^(13)C-labeled wheat straw was applied,and soil samples were collected after rice maturity to analyze various carbon fractions,δ^(13)C values,and soil microbial community composition.The results demonstrated that compared to the N0 treatment,SOC content significantly increased by 7.8%and 7.4%in the N240 and N360 treatments,respectively.Total nitrogen content significantly increased by 37.2%and 34.3%,dissolved organic carbon significantly increased by 33.7%and 48.6%,and microbial biomass carbon significantly increased by 97.9%and 89.6%,respectively.However,compared to N0 treatment,soil carbon-to-nitrogen ratios significantly decreased by 21.6%and 20.0%in N240 and N360 treatments,respectively.In the N120 treatment,no significant differences were observed in SOC,total nitrogen,carbon-to-nitrogen ratio,or dissolved organic carbon compared to the N0 treatment,although microbial biomass carbon content was significantly higher.Moreover,nitrogen fertilization with straw return significantly increased bacterial content by 24.7%to 55.4%,fungal content significantly increased by 18.3%to 30.2%,and total phospholipid fatty acid content significantly increased by 18.1%to 45.2%.Application of nitrogen fertilizer also enhanced the proportion of>2000μm and 250-2000μm aggregates,as well as the organic carbon stock in the free particulate organic carbon(fPOC)and intra-microaggregate particulate organic carbon(iPOC)fractions.Additionally,δ^(13)C values in the fPOC and iPOC fractions significantly increased by 128.3%to 194.8%and 105.6%to 216.9%,respectively.However,at the highest nitrogen

关 键 词：秸秆还田 施氮量 土壤有机碳 溶解性有机碳 稳定同位素标记 土壤微生物 秸秆碳 

分 类 号：S153[农业科学—土壤学]