不同施肥处理对花菜-毛豆轮作系统碳收支的影响

摘要

Based on the time scale of vegetable growing season, from the two aspects: soil carbon sequestration and net ecosystem carbon budget (NECB), under equal nitrogen condition, the effects of three treatments: chemical fertilizer application (H), organic combined with chemical feitilizer (HY) and straw combined with chemical fertilizer (HJ) on carbon budget of cauliflower-soybean rotation system were studied. The aim of this study is to explore the vegetable fertilization pattern of yield increasing and emissions reducing. The results showed that compared to H, HY and HJ increased significantly soil carbon sequestrations by 191.38% and 73.10%. Soil carbon sequestration was positively correlated with organic matter in fertilizer. Soil carbon sequestration under HJ was higher than HY by 30.93%. The NECB values of all the fertilization treatments were in the range of 302~5135 kg?hm-2, which belonged to carbon sink. HY increased significantly the NECB value, which was 16 times higher than H. Compared with HJ and HY, H increased greenhouse gas (CH4 and CO2) emission fluxes respectively by 10.57% and 19.60%. H also decreased soil carbon sequestrations, which was lower than HJ (14.76%) and HY (13.87%). In conclusion, the results of soil carbon sequestration and net ecosystem carbon budget indicated that the organic fertilizer could improve effectively the carbon sink of cauliflower-soybean rotation system. Considering the economic and environmental benefits, HJ is the best fertilization model, which not only can improve the carbon sink, but also can realize the recycling utilization of straw and reduce the application amount of chemical fertilizer, so as to promote the sustainable development of agriculture.%基于蔬菜生长季的时间尺度,从土壤固碳量和净生态系统碳收支(NECB)两个角度,研究等氮条件下,不同施肥模式对花菜-毛豆轮作系统碳收支的影响.试验为大田小区试验,设置单施化肥(H)、商品有机肥配施化肥(HY)、秸秆堆肥配施化肥(HJ)3个施肥处理,旨在探索菜田减排增汇的施肥模式.研究结果显示,(1)有机肥料配施化肥能显著提高土壤固碳量,HJ、HY固碳量分别比H高191.38%和73.10%;土壤固碳量与肥料中有机质的含量有关,HJ固碳量比HY高68.32%.(2)各施肥处理NECB为302~5135 kg?hm-2,均为净碳汇,有机肥配施无机肥能显著提高NECB值,平均较化肥处理(H)NECB高出约16倍.其中,H处理温室气体累积排放量分别比HJ、HY高出10.57%、19.60%,而蔬菜固碳量却较HJ、HY低14.76%、13.87%,表明有机肥配施化肥既可以减排,同时可以提高轮作系统的净碳收支(NECB).总之,土壤固碳量、系统净碳收支两方面的试验结果均表明:有机肥配施无机肥可以有效提高花菜-毛豆轮作系统净碳汇.综合考虑经济、环保效益,HJ是最佳的施肥模式,不仅可以提高花菜-毛豆轮作系统净碳收支,达到减排增汇的效果,而且可以实现秸秆的资源化利用,降低化肥的施用量,有利于农业的可持续发展.