生物质炭与氮肥配施对红壤线虫及土壤酶活性的影响

发布时间：2018-08-17 18:19

【摘要】：作为土壤改良剂,施用生物质炭是一种改善贫瘠或退化土地的有效手段。虽然生物质炭可以增加植物的养分供应,改善土壤的物理化学性质和微生物特性,但仍缺乏生物质炭对土壤动物群落影响的研究。本研究在结合田间定位试验和室内培养试验,探讨了不同量的生物质炭与氮肥配施对红壤物理化学性质、功能指标和土壤生物群落、作物生长的影响。基于田间定位试验,本研究首先探讨了不同用量的生物质炭与氮肥配施对干旱期和湿润期红壤微生物性质和线虫群落的影响。结果表明:(1)生物质炭在干旱期和湿润期均显著影响土壤含水量和pH(P0.05)。随着生物质炭用量的增加,土壤含水量呈先上升后下降的趋势,而土壤pH值保持上升趋势。(2)土壤微生物生物量碳氮、碳氮比及基础呼吸均受到生物质炭和氮肥的显著影响,且低量生物质炭对微生物生物量碳氮、碳氮比及基础呼吸有刺激作用,而高量生物质炭则对其有抑制作用。如生物质炭施用量低于30 thm-2时,在干旱期和湿润期时均促进土壤微生物活性。此外,生物质炭的效果也依赖于不同采样时期。如在施用量高于30 thm-2时,微生物生物量碳在干旱期显著高于对照,在湿润期与对照无显著差异;而微生物生物量氮则呈相反趋势。(3)可溶性有机物和矿质氮在干旱期受到生物质炭和氮肥的显著影响(P0.01),但在湿润期时仅受到氮肥的影响。可溶性有机物和矿质氮随生物质炭用量的增加呈下降趋势。(4)生物质炭、氮肥及二者的交互作用在干旱期和湿润期均显著影响线虫数量及营养类群的结构。高量生物质炭和氮肥配施提高土壤线虫的数量。值得注意的是,生物质炭显著提高了干旱期食真菌线虫的比例,尤其在干旱期趋势明显,暗示生物质炭作用下土壤食物网结构趋向于以真菌主导的能流通道。(5)冗余分析表明土壤微生物性质、土壤养分与线虫群落显著相关。在干旱期,可溶性碳氮、矿质氮、含水量、pH和基础呼吸与线虫群落关系较密切;在湿润期,可溶性碳氮、矿质氮、微生物生物量氮和微生物量碳氮比与线虫群落联系密切。在田间试验调查的基础上,通过盆栽调控试验进一步在玻璃温室控制条件下研究了不同用量生物质炭和氮肥配施对土壤理化性质、微生物学性质、土壤功能及微型动物(原生动物和线虫)的影响。结果表明:(1)生物质炭、氮肥及二者交互作用显著影响土壤湿度和pH,在油菜开花期和成熟期时,随生物质炭施用量的增加,土壤含水量降低而土壤pH呈上升趋势。采样时间对土壤湿度和pH的影响达到极显著水平(P0.01)。(2)生物质炭和氮肥显著影响可溶性有机物、矿质氮和速效磷,且其交互作用对矿质氮影响显著。在开花期和成熟期时,单施生物质炭降低了土壤可溶性有机碳和氮的含量,而增加了土壤速效磷含量。与开花期相比,成熟期时生物质炭和氮肥配施提高了可溶性有机物和矿质氮含量,降低了速效磷含量。(3)土壤微生物生物量碳受到生物质炭的显著影响。在开花期和成熟期时,随生物质炭用量的增加,土壤微生物碳氮一般呈现先升高后下降的趋势。氮肥显著影响土壤微生物活性,且与生物质炭交互作用达到显著水平。开花期时,施入生物质炭促进土壤微生物活性;成熟期时处理间则无明显差异。采样时间对基础呼吸、微生物生物量磷的影响达到极显著水平。(4)在开花期时,生物质炭提高了鞭毛虫的数量,降低了变形虫和线虫的数量;在成熟期时,随生物质炭用量的增加,原生动物数量和线虫数量呈下降趋势;与开花期相比,成熟期食细菌线虫比例下降,其他营养类群的比例则呈增加趋势。成熟期时,生物质炭和氮肥配施提高了食真菌线虫的比例,降低了线虫通道指数,表明以真菌为主导的能流通道逐渐加强。(5)非度量多维尺度分析表明,采样时间影响土壤线虫群落的程度比处理之间的差异更大。由相关分析得到,可溶性碳氮、含水量、速效磷、pH和土壤基础呼吸对线虫群落的影响较大。(6)参与土壤碳、氮、磷循环的酶活性受到生物质炭和氮肥及其交互作用的显著影响。低量生物质炭对酶活性有一定的刺激作用,高量生物质炭则抑制酶活性。生物质炭和氮肥配施后,酶活性在成熟期时最低。此外,表征碳、氮、磷循环的酶及其总酶与土壤含水量、速效磷、矿质氮和基础呼吸呈显著正相关,而与可溶性碳氮、微生物生物量磷显著负相关。(7)生物质炭、氮肥及其交互作用对油菜生物量有极显著影响(P0.01)。油菜开花期和成熟期,生物质炭和氮肥配施有明显的协同交互作用,即高量生物质炭和高量氮肥配施时,油菜生物量最高。油菜产量受到生物质炭的显著影响(P0.05),生物质炭施用量的增加也伴随着油菜产量的显著增加。其中,油菜产量和植株生物量与pH呈正相关,与土壤湿度和矿质氮呈显著负相关。田间试验和室内培养试验均表明土壤微生物学性质和原生动物、线虫群落受到生物质炭和氮肥配施的影响。
[Abstract]:Biochar, as a soil amendment, is an effective means to improve poor or degraded land. Although it can increase the nutrient supply of plants and improve the physical and chemical properties and microbial characteristics of soil, there is still a lack of research on the effects of biochar on soil fauna communities. This study is conducted in combination with field experiments and laboratories. The effects of different amounts of biomass carbon and nitrogen fertilizer on the physicochemical properties, functional indices, soil biological community and crop growth of red soil were studied in the field incubation experiment. The results showed that: (1) Biochar significantly affected soil water content and pH during drought and wet periods (P 0.05). With the increase of biomass carbon, soil water content increased first and then decreased, while soil pH maintained an upward trend. (2) Soil microbial biomass C-N, C-N ratio and basal respiration were all affected by biochar. The low biomass char could stimulate the microbial biomass C N, C N ratio and basal respiration, while the high biomass char could inhibit it. For example, when the biomass char application rate was lower than 30 thm-2, the soil microbial activity was promoted in both dry and wet periods. For example, when the application rate was higher than 30 thm-2, the microbial biomass carbon in drought period was significantly higher than that in control, but there was no significant difference in wet period, while the microbial biomass nitrogen showed the opposite trend. (3) Soluble organic matter and mineral nitrogen were significantly affected by biomass carbon and nitrogen fertilizer in drought period (P 0.01), but in wet period. Soluble organic matter and mineral nitrogen decreased with the increase of biomass carbon application. (4) Biochar, nitrogen fertilizer and their interaction significantly affected the number of nematodes and the structure of vegetative groups during drought and wet periods. Biochar significantly increased the proportion of fungi-eating nematodes during drought, especially during drought, suggesting that the structure of soil food web tended to be fungal-dominated energy-flow pathway. Mineral nitrogen, water content, pH and basal respiration were closely related to nematode community; soluble carbon and nitrogen, mineral nitrogen, microbial biomass nitrogen and microbial biomass carbon and nitrogen ratio were closely related to nematode community in wet period. The results showed that: (1) Biochar, nitrogen fertilizer and their interaction significantly affected soil moisture and pH. At flowering and maturing stages of rape, soil water content increased with the increase of biomass char application. The effect of sampling time on soil moisture and pH reached a very significant level (P 0.01). (2) Biochar and nitrogen fertilizer significantly affected soluble organic matter, mineral nitrogen and available phosphorus, and their interaction had a significant effect on mineral nitrogen. Compared with flowering stage, the content of soluble organic matter and mineral nitrogen was increased and the content of available phosphorus was decreased at maturity stage. (3) Soil microbial biomass carbon was significantly affected by biomass carbon. Soil microbial C and N increased first and then decreased. Nitrogen fertilizer significantly affected soil microbial activity, and the interaction with biomass carbon reached a significant level. (4) Biochar increased the number of flagellates and decreased the number of amoebas and nematodes at flowering stage, decreased the number of protozoa and nematodes at maturity stage, and decreased the proportion of bacterial-eating nematodes at maturity stage compared with flowering stage. At maturity stage, the proportion of fungal nematodes increased and the nematode channel index decreased with the application of biomass carbon and nitrogen fertilizer. (5) Non-metric multidimensional scale analysis showed that sampling time affected soil nematode community more than the difference between treatments. (6) Enzyme activities involved in soil carbon, nitrogen and phosphorus cycling were significantly affected by biomass carbon and nitrogen fertilizer and their interactions. Low biomass carbon stimulated enzyme activities, while high biomass carbon stimulated enzyme activities. Inhibitory enzyme activity was lowest at maturity stage after application of biomass carbon and nitrogen fertilizer. In addition, enzymes and total enzymes characterizing carbon, nitrogen and phosphorus cycling were positively correlated with soil water content, available phosphorus, mineral nitrogen and basal respiration, but negatively correlated with soluble carbon and nitrogen and microbial biomass phosphorus. The biomass of rape was significantly affected by the combination of biomass carbon and nitrogen fertilizer at flowering stage and maturity stage (P 0.01). The biomass of rape was the highest when high biomass carbon and nitrogen fertilizer were applied together. The yield of rape was significantly affected by biomass carbon (P 0.05), and the increase of biomass carbon application was accompanied by the increase of biomass carbon application rate. The yield of rape and plant biomass were positively correlated with pH, negatively correlated with soil moisture and mineral nitrogen. Field and laboratory experiments showed that soil microbial properties and protozoa, nematode communities were affected by the combination of biomass carbon and nitrogen fertilizer.
【学位授予单位】：南京农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S154

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