堆肥中生物可利用有机碳的鉴别和评价

发布时间：2019-07-06 07:17

【摘要】：我国有机堆肥的产量大、种类多,但有机堆肥的质量标准中对有机碳的指标单一,对于添加煤矸石等物质作为有机质对农田的生态安全性缺乏科学研究。本论文在系统分析不同来源的有机堆肥中有机碳的组成以及利用堆肥进行盆栽试验的基础上,着重探讨了不同类型有机碳(总有机碳TOC、易氧化有机碳LOC、水溶性有机碳WSOC和低分子量有机碳LMWOM)的生物可利用性和生物降解性,为堆肥肥效与生态安全性评价提供依据。为了阐明作物对堆肥中有机质消耗利用规律的认识,在四种堆肥(C1~C4)的盆栽试验中对四种作物(青瓜、西红柿、番薯、玉米)栽培前后的堆肥有机质的消耗进行了定量分析,采用重铬酸钾氧化—容量法测定了TOC。发现作物在不同栽培基质上的生长情况普遍存在差异,且堆肥对不同作物的生长影响也存在明显差异,说明堆肥和作物之间存在相互选择性,因此应该尽可能视作物种类施用合适堆肥。不栽种作物的空白组对有机质消耗率最大为42%,栽种作物的实验组中,除青瓜外,其他三种作物对堆肥基质中有机质的消耗均达到90%以上,最大达99.9%。说明作物栽培显著促进了有机质的消耗,在种植作物前,应该尽可能视作物种类施用充足的有机肥底肥,减少对土壤有机质的消耗。试验中一次种植后基质中的有机质即降至4.2%~12.6%,接近耕作层土壤的普通有机质含量水平,对于耕作密度强度大的农田,有必要坚持长期施用有机肥,确保农田的土壤性能优良。为有效评估堆肥中有机碳的含量及其对作物的影响,借助相关性分析统计方法,探讨了堆肥中不同类型有机碳对作物生长的影响。研究表明较之总有机碳,易氧化性有机碳(LOC)与作物生长更密切,更灵敏地反映堆肥的肥效。以番薯为例,TOC、LOC、WSOC与作物生物量之间的相关系数分别为0.100、0.699、-0.004,LOC与作物生物量呈显著正相关,WSOC则呈弱负相关。因此,在堆肥工艺上应该通过避免过度氧化LOC以保证其含量,并保证充分腐熟来减少WSOC等措施来控制堆肥产品的有机碳指标。现有国家堆肥质量准标中仅有有机质指标,不能客观地反映有机堆肥的质量,有必要增加LOC和WSOC的含量指标。为了初步探究堆肥中低分子量有机碳被作物直接吸收利用的“碳肥”效应,利用顶空萃取-气相色谱-质谱(HS-GC-MS)法对堆肥与栽培基质中的LMWOM进行定性和定量分析。研究表明,堆肥中含有多种低分子有机物,其中低分子量醛类有机物质相对含量相对较高。除C1基质外,与不栽培作物的空白组对比,青瓜和玉米的栽培基质中的醛类物质普遍都有增加,说明作物在生长过程中会促使低分子量醛类物质的产生。作物生长与醛类物质密切相关。为了评估堆肥中有机碳的生态安全性,通过盆栽实验探讨了商品堆肥中添加煤矸石作有机质对作物和栽培基质的影响。结果表明煤矸石对土壤微生物有明显抑制。考虑到对土壤微生物的负面影响,应该从有机肥生产源头避免在堆肥中添加煤矸石。为进一步探讨煤矸石的生物可利用性,用不同来源的微生物作为接种物,按照国际标准OECD 301B开展了生物降解试验。结果表明:经过28d的微生物降解,煤矸石在活性污泥中的降解率为21.9%,在菜园土中的降解率为14.4%,初步说明煤矸石不具有快速生物降解性。煤矸石作为外加碳源添加到有机堆肥中,虽然能够提高堆肥中的总有机碳含量,但这种碳元素难以生物利用,具有环境持久性,长期施用对农田的生态安全有潜在的风险。
[Abstract]:There are many kinds of organic compost in China, but the index of organic carbon is single in the quality standard of organic compost. On the basis of system analysis of the composition of organic carbon in organic composts of different sources and the use of compost for pot experiment, the organic carbon (TOC) of different types (TOC) and the organic carbon (LOC) are discussed. Bioavailability and biodegradability of water-soluble organic carbon (WSOC) and low-molecular-weight organic carbon (LMWOM) provide a basis for the evaluation of the fertilizer efficiency and ecological safety of the compost. In order to understand the law of the utilization of organic matter in the compost, a quantitative analysis of the consumption of the composted organic matter before and after the cultivation of four kinds of crops (green, tomato, sweet potato, and corn) was carried out in the pot experiment of four kinds of compost (C1-C4). The TOC was determined by the method of potassium dichromate oxidation and capacity determination. There was a significant difference in the growth of the crops on different cultivated substrates, and there was a significant difference in the effects of the compost on the growth of different crops, indicating the mutual selectivity between the compost and the crop, and the appropriate compost should be applied as much as possible. In the experimental group, the consumption of organic matter in the compost matrix was over 90% and the maximum of 99.9%. The method of the invention can obviously promote the consumption of organic matters, and before planting the crops, the sufficient organic fertilizer base fertilizer should be applied to the crop type as much as possible to reduce the consumption of organic matter in the soil. In the experiment, the organic matter in the matrix is reduced to 4.2%-12.6%, and the organic matter content in the soil near the farming layer is close to that of the soil in the farming layer. For the farmland with large cultivated density, it is necessary to adhere to the long-term application of the organic fertilizer, so as to ensure the good soil performance of the farmland. In order to effectively evaluate the content of organic carbon in compost and its effect on crops, the effects of different types of organic carbon on the growth of crops were discussed by means of correlation analysis. The results show that the organic carbon (LOC) is more closely related to the growth of the crops than the total organic carbon, and the fertilizer efficiency of the compost is more sensitive. Taking sweet potato as an example, the correlation coefficient between the TOC, LOC, WSOC and crop biomass was 0.100, 0.699,-0.004, LOC was positively correlated with the crop biomass, and the WSOC was negatively correlated. Therefore, the organic carbon index of the composted product should be controlled by avoiding over-oxidation of LOC in the composting process to ensure its content, and ensuring adequate decomposition to reduce the WSOC. It is necessary to increase the content index of LOC and WSOC in the existing national compost quality standard with only the organic matter index, which can not objectively reflect the quality of the organic compost. In order to study the "carbon fertilizer" effect of direct absorption and utilization of low molecular weight organic carbon in compost, the qualitative and quantitative analysis of the LMWOM in the composted and cultivated substrate was carried out by using the headspace extraction-gas chromatography-mass spectrometry (HS-GC-MS) method. The results show that the relative content of low molecular weight aldehydes is relatively high in the compost. In addition to the C1 matrix, there is an increase in the number of aldehydes in the cultivation matrix of the green and corn, indicating that the production of low-molecular-weight aldehydes is promoted in the growing process of the crop, compared with the blank group of the non-cultivated crop. The growth of crops is closely related to the aldehydes. In order to evaluate the ecological security of organic carbon in compost, the effect of organic matter on crop and culture matrix was discussed by pot experiment. The results show that the coal-stone is obviously inhibited by the soil microorganisms. In view of the negative impact on the soil microorganisms, it should be avoided from the production of organic fertilizer to avoid the addition of coal and stone in the compost. In order to further explore the bioavailable properties of the coal and stone, the biodegradation test was conducted in accordance with the International Standard OECD 301B using a different source of microorganism as the inoculum. The results showed that the degradation rate of coal-fired stone in activated sludge was 21.9%, and the degradation rate in vegetable garden soil was 14.4%. The addition of coal-stone as an external carbon source to the organic compost, although the total organic carbon content in the compost can be improved, the carbon element is difficult to be bioutilized, has environmental durability, and has a potential risk for long-term application to the ecological safety of the farmland.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S141.4

【相似文献】