连续炭基肥替代化肥对菜园土壤性质和细菌群落结构的影响

Effects of Continuous Biochar-based Fertilizer Replacement on Soil Properties and Bacterial Community Structure in Vegetable Garden

摘要:

为了解生物炭基肥替代化肥减量施用的田间长期效应，利用定位试验研究连续5 a炭基肥替代化肥对蔬菜产量、土壤理化性质和细菌群落结构的影响。结果表明，连续5 a实施炭基有机肥替代化肥，土壤pH提高了0.13~0.25，土壤有机质、碱解氮和有效磷含量也分别提高了2.1%~62.2%、5.8%~86.0%和0.4%~103.1%，炭基肥替代化肥处理的荠菜(Capsella bursa- pastoris)产量提高了4.0%~14.8%，但75%替代处理较50%替代处理有所降低。炭基肥替代化肥处理的土壤菌群Sobs、Shannon、Ace和Chao指数均高于单施化肥处理，且均以75%替代处理最高。炭基肥替代化肥显著降低了土壤中硝化菌属(Nitrolancea)、拟无枝酸菌属(Amycolatopsis)、芽单胞菌属(Gemmatimonas)等的丰度，增加了纤维素降解菌菌群(Planifilum、Saccharomono-spora)的丰度。芽单胞菌属、Ilumatobacteraceae、Methyloligellaceae等的丰度与土壤全氮、全磷、有机质间具有显著的相关性。可见，连续炭基肥替代化肥明显改善了菜地土壤的理化性质，从而影响了土壤细菌群落结构和多样性，适量替代可以提高蔬菜产量，但应注意长期连续施用对土壤pH、碳/氮的影响，避免过量施用抑制作物对养分的吸收利用。

Abstract:

In order to understand the field long-term effect of biochar-based fertilizer instead of chemical fertilizer, the vegetable yield, soil physical and chemical properties and bacterial community structure with biochar-based fertilizer replacement for 5 consecutive years were studied by localization experiment. The results showed that soil pH increased 0.13-0.25 after 5 years, and the contents of organic matter, alkali-hydrolyzable nitrogen and available phosphorus in soils increased 2.1%-62.2%, 5.8%-86.0% and 0.4%-103.1%, respectively. The yield of Capsella bursa-pastoris with biochar-based fertilizers increased by 4.0%-14.8% than that of the control, but the yield under 75% replacement was lower than that of 50% replacement. The indexes of Sobs, Shannon, Ace and Chao of soil bacteria with biochar-based fertilizer were higher than those of chemical fertilizer, and those under 75% replacement were the highest. Compared to chemical fertilizer, the abundances of Nitrolancea, Amycola- topsis and Gemmatimonas with biochar-based fertilizer decreased significantly, and the abundances of cellulose-degrading bacterial increased, such as Planifilum and Saccharimonadales. There were significant correlations between the abundances of Gemmatimonas, Ilumatobacteraceae, Methyloligellaceae, and soil total nitrogen, total phosphorus, organic matter. Therefore, the replacement of continuous biochar-based fertilizer significantly improved soil physical and chemical properties, and caused the changes in bacterial community structure and diversity. Appropriate replacement of biochar-based fertilizers could increase vegetable yield, but the effect of long-term continuous application on soil pH and C/N should be paid attentions, so as to avoid excessive application inhibiting nutrients uptake and utilization by crops.