生物有机肥对马铃薯产量与土壤氮循环作用机制研究

Mechanism of Bio-organic Fertilizer on Potato Yield and Soil Nitrogen-cycling

为探讨煤基生物有机肥对滴灌条件下马铃薯产量和土壤理化特性及氮循环相关功能微生物丰度的影响,揭示煤基生物有机肥对作物产量和土壤氮循环的作用机制,在施用相同化肥基础上,分别增施0、1500、3000、4500 kg/hm^(2)(CF、BF1、BF2、BF3处理)煤基生物有机肥开展田间试验。结果表明:与CF相比,增施煤基生物有机肥显著增加了植株和块茎干物质积累量,显著提高块茎总产量5.30%~9.49%,且随增施量的增加而增加;显著降低了土壤pH值,增加了有机碳含量。随有机肥增施量的增加,土壤细菌和真菌丰度呈现减少趋势,但均高于CF。增施煤基生物有机肥显著提高了亚硝酸盐还原酶基因(nirS)丰度,对固氮酶基因(nifH)和氨氧化细菌(AOB)的氨单加氧酶基因(amoA)丰度提高不显著。土壤有机碳是驱动nirS型反硝化菌丰度的重要环境因子。适宜增施煤基生物有机肥可以调控土壤细菌和真菌占比,调节土壤氮循环过程,与其他功能基因相比,nirS基因丰度变化对煤基生物有机肥的添加更为敏感。增施煤基生物有机肥有助于提升马铃薯田生产力,以增施4500 kg/hm^(2)煤基生物有机肥最佳。

The effects of coal-based bio-organic fertilizer on potato yield,soil physical and chemical properties and abundance of nitrogen-cycling microbes under drip irrigation were studied,aiming to reveal the mechanism of the fertilizer on crop yield and soil nitrogen cycle.A field experiment was conducted from May to September in 2019,located in Guyang County,Inner Mongolia.Totally 1500 kg/hm^(2)(BF1),3000 kg/hm^(2)(BF2),4500 kg/hm^(2)(BF3)of coal-based bio-organic fertilizer and no organic fertilizer(CF)were applied respectively on the same levels of chemical fertilizations.The chemical fertilizers were 210 kg/hm^(2) of nitrogen(N),150 kg/hm^(2) of phosphorus(P_(2)O_(5))and 180 kg/hm^(2) of potassium(K_(2)O).The field experiment included four treatments and each treatment was repeated three times.Plant dry matter accumulation and tuber yield were quantified at potato maturity and harvest periods,respectively.Samples were collected from 0~20 cm layer for analysis of physicochemical properties of soil and abundances of nitrogen cycling microbes before tuber harvesting.The abundances of bacteria(16S rRNA),fungi(ITS)and nitrogen cycle functional genes(nirS,ammonia-oxidizing bacteria amoA,nifH)were quantified by quantitative real-time PCR techniques.Compared with CF,increasing the coal-based bio-organic fertilizer ratio could significantly increase the dry matter accumulation of plant and tuber.The total tuber yield was increased by 5.30%~9.49%with the organic fertilizer increasing.The soil pH value of organic fertilizer treatments was significantly lower but organic carbon content was higher than that of CF.The abundance of soil bacteria and fungi was decreased with the increase of organic fertilizer application,but it was higher than that of CF.The abundance of microbial genes related to soil nitrogen-cycling responded positively to the addition of organic fertilizer.Furthermore,the gene abundance of nitrite reductase(nirS)was significant,while nitrogenase(nifH)and ammonia monooxygenase(amoA)of ammonia-oxidizing bacteria(AOB)were not significant.The content of soil organic carbon appeared to be the key factor influencing the abundance of nirS-type denitrifying bacteria.Overall,these results indicated that the proportion of soil bacteria and fungi could be regulated through proper application of the coal-based bio-organic fertilizer.Soil nitrogen cycle would be affected by the coal-based bio-organic fertilizer.The abundance of nirS gene was more sensitive to the addition of organic fertilizer than that of other functional genes.The coal-based bio-organic fertilizer would help to improve the productivity of potato fields,and the application of 4500 kg/hm^(2) had a better performance.