长期施用有机肥对潮土区甘薯碳氮积累与分配的影响

Effects of Long-Term Application of Organic Fertilizer on Carbon and Nitrogen Accumulation and Distribution of Sweetpotato in Fluvo-Aquic Soil Area

【目的】甘薯碳氮积累与分配是影响产量形成的关键因素。研究长期有机肥料添加条件下甘薯碳氮积累与分配的响应关系,为实现潮土区甘薯高产高效栽培提供科学依据。【方法】以40年潮土长期定位试验(徐州)为平台,选择不施肥(CK)、施氮磷钾肥(NPK)、施有机肥料(M)、有机肥料+氮磷钾肥处理(MNPK)处理作为研究对象,测定分析不同施肥措施下耕作层土壤性质、甘薯收获期的地上/地下部生物量以及各主要功能器官的碳氮含量,阐明不同施肥处理对甘薯碳氮含量及其在各功能器官中的分配比例的影响,以及不同施肥措施下甘薯地上、地下部碳氮比(C/N)的变化,并运用主成分分析法解析甘薯碳氮分配与土壤性质的关系。【结果】长期有机肥配施氮磷钾化肥(MNPK),相较单施有机肥料(M)或化肥(NPK),甘薯块根生物量与干物质量显著提高(P<0.05)。同时土壤全氮、速效钾含量均显著提高(P<0.05)。通过对土壤性质与甘薯碳氮固持及碳氮比之间的相关性分析表明,甘薯各器官碳氮固持量与土壤有机碳(SOC)、全氮(TN)、速效钾含量呈极显著正相关(P<0.01)。而土壤有效磷(AP)含量并未与甘薯叶片碳氮含量表现出相关关系,但与块根氮固持量呈极显著正相关(P<0.01),相关系数达0.839。甘薯叶片C/N与土壤EC呈极显著正相关(P<0.01),叶柄与藤蔓C/N与土壤EC呈极显著负相关(P<0.01),甘薯地下块根C/N与土壤有效磷含量呈极显著负相关(P<0.01)。通过对碳氮固持量在地上部、地下部的分配比例以及地上部、地下部的C/N进行主成分分析(PCA),结果表明前两个轴共同解释了66.6%的变异,第一主成分轴贡献率为42.8%。CK与NPK处理在轴1上的排序较高,说明两者处理下土壤pH与EC值较高,且对于碳氮在甘薯地上部的分配以及地下部C/N的解释度较高。【结论】有机物料添加能够合理调配各器官C/N,提高碳氮在甘薯地下块根部分的分配比例,促进甘薯产量的形成。

【Objective】The accumulation and distribution of carbon and nitrogen in sweet potato is the key factor of yield formation,the response relationship between carbon and nitrogen accumulation and distribution in sweetpotato under long-term organic fertilizer addition was studied to provide scientific basis for high-yield and high-efficiency cultivation of sweetpotato in fluvo-aquic soil region.【Method】Based on the 40-year long-term locating test of fluvo-aquic soil(Xuzhou),the treatments of no fertilizer(CK),nitrogen,phosphorus and potassium fertilizer(NPK),organic fertilizer(M),organic fertilizer+nitrogen,phosphorus and potassium fertilizer(MNPK)were selected as the research objects,soil properties,aboveground/underground biomass and carbon and nitrogen contents of main functional organs of sweet potato under different fertilization measures were measured and analyzed,the effects of different fertilization treatments on the content of carbon and nitrogen in sweet potato and the distribution ratio of carbon and nitrogen in various functional organs,as well as the changes of the ratio of carbon and nitrogen(C/N)in the aboveground and underground parts of sweet potato under different fertilization measures were expounded.The relationship between the distribution of carbon and nitrogen in sweet potato and soil properties was analyzed by principal component analysis.【Result】Compared with single application of organic fertilizer(M)or chemical fertilizer(NPK),long-term application of organic fertilizer combined with nitrogen,phosphorus and potassium fertilizer(MNPK)significantly increased the biomass and dry matter quality of sweet potato root tuber(P<0.05).At the same time,the contents of total nitrogen and available potassium in soil were significantly increased(P<0.01).The correlation analysis between soil properties and C/N fixation and C/N ratio of sweet potato showed that the C/N fixation of sweet potato organs was significantly positively correlated with soil organic carbon(SOC)and total nitrogen(TN)(P<0.01),and significantly positively correlated with soil available potassium(AK)(P<0.05).However,the content of soil available phosphorus(AP)was not correlated with the content of carbon and nitrogen in sweet potato leaves,but positively correlated with the nitrogen fixation of root tuber(P<0.01),with a correlation coefficient of 0.839.The C/N ratio of leaves of sweet potato was positively correlated with soil EC(P<0.01),and the C/N ratio of petioles and stems of sweet potato was negatively correlated with soil EC(P<0.01).The C/N ratio of underground tubers of sweet potato was negatively correlated with soil available phosphorus(P<0.01);principal component analysis(PCA)was used to analyze the distribution ratio of carbon and nitrogen fixation in aboveground and underground parts and the C/N ratio of aboveground and underground parts.The results showed that the first two axes explained 66.6% of the variation,and the contribution rate of the first principal component axis was 42.8%.The order of CK and NPK treatments on axis 1 was higher,which indicated that the soil pH and EC values were higher under both treatments,and the explanations for the distribution of carbon and nitrogen in the aboveground part and C/N in the underground part of sweet potato were higher.【Conclusion】It can be seen that organic material addition can reasonably allocate C/N of each organ,improve the distribution ratio of carbon and nitrogen in the storage root part of sweetpotato,and promote the formation of sweetpotato yield.