长期定位施肥对黑土养分平衡和胡敏素分子结构动态变化的影响

Effects of Long-Term Localized Fertilization on Nutrient Balance and Dynamic Change of Hu Molecular Structure in Black Soil

以黑土长期定位试验(始于1979年)为基础,根据土壤养分的输入和输出分析长期不同施肥处理的土壤养分收支状况。利用红外光谱和核磁共振光谱分析胡敏素(Humin,Hu)分子结构的动态变化特征并分析土壤养分收支状况与Hu结构变化之间的关系。结果表明:不同施肥措施在改变黑土养分含量的同时,影响了土壤中惰性组分Hu的分子结构。1980年—2014年有机无机肥配施(MNPK)处理可以满足作物对养分的吸收,土壤总养分含量有盈余,且较不施肥(CK)处理增加土壤有机碳含量,降低土壤C/N比,同时土壤Hu的2 920/1 620和2 920/2 850、脂族C/芳香C、烷基C/烷氧C和疏水C/亲水C比值均增加,表明黑土Hu分子结构变得脂族化、简单化,施肥可以增加土壤活性有机碳,减少惰性有机碳组分含量。有机肥(M)和氮磷钾化肥(NPK)处理不能满足作物对养分的吸收,土壤养分出现亏缺状况。红外光谱显示,施肥年限增加,有机肥(M)和氮磷钾化肥(NPK)处理土壤Hu的2 920/1 620下降,表明其脂族C含量降低;核磁共振光谱显示,氮磷钾化肥(NPK)和不施肥(CK)处理烷基C/烷氧C降低,表明其活性有机碳含量下降。虽然各施肥处理较不施肥(CK)处理整体增加土壤Hu的脂族C含量,降低芳香C含量,但随着施肥年限的增加,氮磷钾化肥(NPK)处理使土壤Hu结构有变复杂化的趋势。各养分盈亏量与土壤Hu的结构特征参数之间具有相关性,N,P_2O_5和K_2O养分盈亏量和总养分盈亏量与2 920/1 620、脂族C呈正相关,与芳香C呈负相关,表明养分状况可以影响土壤Hu的结构。节约经济成本情况下,轮作周期内施入一次有机肥,每年结合氮磷钾化肥的施入可以满足作物对养分的吸收,在提高作物产量的同时,改善土壤腐殖质惰性组分结构,培肥地力。

The study was based on the long-term black soil positioning test(beginning in 1979),and according to the input and output of soil nutrient,the soil nutrien t ba lance of different fertilization treatments was analyzed.The dynamic characteri stics of Hu molecular structure were analyzed by infrared and nuclear magnetic resonance spectroscopy,and the relationship between soil nutrient budget and th e change of Hu structure was analyzed.The result shows:different fertilization measures changed the molecular structure of the inert component Hu in the soil while changing the nutrient content of black soil.From 1980 to 2014,organic a nd inorganic fertilizer(MNPK)treatment to meet the crop nutrient absorption,the total soil nutrient content was surplus,and the soil organic carbon content was increased and soil C/N ratio was decreased without CK treatment.At the sam e time,the ratio of 2 920/1 620 and 2 920/2 850,aliphatic C/,aromatic C,alkyl C/,alkoxy C and hydrophobic C/,hydrophilic C increased in the soil Hu,indicating that the molecular structure of black soil Hu became aliphatic and simplified.Fertilization can increase soil active organic carbon and reduce th e content of inert organic carbon components.Organic fertilizer(M)and nitroge n,phosphorus and potassium fertilizer(NPK)could not meet the nutrient uptake of crops,and the soil nutrient deficit appeared.Infrared spectrum display,w ith the increase of fertilization years,the Hu of 2 920/1 620 decreased with o rganic manure(M)and nitrogen phosphorus potassium fertilizer(NPK)treatment,indicating that the content of aliphatic C decreased.Nuclear magnetic resonanc e spectroscopy showed that the treatment of alkyl C/alkoxide C decreased with NPK and non-fertilization(CK),indicating that the activity of organic carb on decreased.Although the treatments of fertilizer application without fert ilization(CK)increased the soil Hu lipid C content and decreased the aromatic C content,with the increase of fertilization years,the treatment of nitro gen,phosphorus and potassium fertilizer(NPK)resulted in the change of soil H u structure.There is a correlation between the nutrient deficit and the structu ral parameters of soil Hu,N,P2O5,K2O nutrient budget and total nutrie nt budget and 2 920/1 620 positive,aliphatic C,aromatic C was negatively cor related with the nutrient status,that can affect the structure of soil Hu.In the case of saving economic cost,the application of organic fertilizer in the r otation cycle,combined with the application of nitrogen,phosphorus and potassi um fertilizer per year can meet the crop nutrient absorption,improving soil humus inert component structure while improving crop yield.