不同有机物料对洱海流域农田土壤温室气体排放的短期影响

Short Term Effect of Different Organic Materials Addition on Greenhouse Gas Emission of Agricultural Soil in Erhai Lake Basin

本研究旨在探明不同有机物料施用对洱海流域露地蔬菜和水旱轮作2种典型种植模式农田土壤温室气体排放的影响。采用室内培养试验,设置了不添加有机物料(CK)、秸秆、生物炭和牛粪添加4个处理,在恒温恒湿下培养15 d。结果表明:(1)与CK相比,有机物料对菜地土壤N_(2)O排放均有抑制作用,对水旱轮作土壤则为促进作用,其中秸秆的促进作用最高。与秸秆处理相比,生物炭和牛粪处理水旱轮作土壤N_(2)O排放分别降低了64.9%和68.3%(P<0.05)。3种有机物料均降低了菜地土壤N_(2)O排放比率,但仅秸秆添加显著增加了水旱轮作土壤N_(2)O排放比率(P<0.05)。(2)与CK相比,生物炭和牛粪处理对菜地和水旱轮作土壤CO_(2)排放均表现出轻微的抑制作用,生物炭和牛粪处理CO_(2)排放量比秸秆处理分别降低了84.9%~85.1%和41.7%~43.1%(P<0.05)。(3)有机物料添加增加了菜地土壤CH_(4)排放量,而仅秸秆添加提高了水旱轮作土壤CH_(4)排放量(P<0.05)。(4)与CK相比,有机物料添加后菜地土壤硝化速率显著升高(P<0.05),土壤矿化速率也均升高,但仅秸秆和牛粪处理效果显著(P<0.05);而水旱轮作土壤硝化速率和矿化速率则均有所降低,其中秸秆和生物炭显著降低(P<0.05)。长期仅施有机肥的水旱轮作农田土壤全球增温潜势比菜地高,其中秸秆添加显著提高了水旱轮作土壤增温潜势,而3种有机物料均显著降低了菜地土壤增温潜势。研究可为洱海流域农田合理添加有机物料以降低温室气体排放和提高土壤供氮能力提供了科学依据。

Organic material application is an important measure for agricultural soil fertility improvement and has a great effect on soil greenhouse gas emissions.To explore the effect of the addition of different organic materials on soil greenhouse gas emissions from typical open field vegetable and rice-rotated planting patterns in the Erhai Lake basin,the incubation experiment was conducted with four treatments,including no addition(CK),straw,biochar and cow manure addition for 15 days under constant temperature and humidity.The results showed that:(1)compared with CK treatment,the addition of three organic materials all had a reduction trend for vegetable soil N_(2)O emissions,but an increase for rice-rotated soil,of which the straw addition had a significant increase effect.Compared with straw treatment,soil N_(2)O emissions from rice-rotated soil under biochar and cow manure treatments declined by 64.9%and 68.3%,respectively(P<0.05).The N_(2)O emission ratio of open field vegetable soil was reduced by all three organic materials(P<0.05),while only straw significantly increased the soil N_(2)O emission ratio of rice-rotated soil.(2)The biochar and cow manure treatments had a slight inhibiting effect on soil CO_(2) emissions for two soils compared with CK treatment.Compared with straw treatment,the biochar and cow manure treatments significantly reduced soil CO_(2) emissions from open field vegetable and rice-rotated soil by 84.9%-85.1%and 41.7%-43.1%,respectively(P<0.05).(3)The addition of organic materials increased the soil CH_(4) emission from open field vegetable soil,while only straw addition increased the soil CH_(4) emission from rice-rotated soil(P<0.05).(4)Compared with CK treatment,soil nitrification rate of open field vegetable soil was significantly increased after organic material addition(P<0.05),and soil mineralization rate was also increased,but only straw and cow manure treatment had significant effects(P<0.05).However,the nitrification rate and mineralization rate of rice-rotated soil after organic material addition were both reduced compared with CK treatment,of which straw and biochar significantly decreased the two rates(P<0.05).The soil N_(2)O and CO_(2) emissions of rice-rotated system with only organic fertilizer were significantly higher than those of open field vegetable system with organic and inorganic fertilizer application,and the soil N_(2)O and CO_(2) emissions were significantly increased after the addition of straw.The global warming potential(GWP)of rice-rotated soil with long-term application of organic fertilizer was higher than that of open field vegetable soil,and the addition of straw significantly increased GWP of rice-rotated soil,while the addition of organic matter significantly reduced GWP of open field vegetable soil.This study provided a scientific basis for the appropriate addition of organic materials to farmland in the Erhai Lake basin to reduce greenhouse gas emissions and improve soil nitrogen supply capacity.