施肥对不同肥力水平春玉米农田土壤有机碳及其组分的影响

Effect of fertilization on soil organic carbon and its fractions under different yield levels of spring corn

选取辽河灌区不同肥力水平春玉米（Zea mays ssp.mays L.）农田土壤为研究对象,通过连续3年田间定位试验研究施肥对不同层次土壤有机碳组分（TOC、ASOC、LFOC、DOC和MBC）的影响,分析土壤有机碳组分的产量效应。结果表明,连续种植春玉米能够显著增加低产田土壤w（TOC）,增加各产田土壤w（ASOC）和w（MBC）,降低各产田土壤w（LFOC）,土壤w（DOC）变化较小。施肥使土壤w（TOC）增加了-13.41%～7.54%,平均增加了0.16%;使高产田表层（0-10 cm）土壤w（TOC）显著增加,低产田犁底层（20-40 cm）土壤w（TOC）显著降低。施肥使土壤w（ASOC）增加了-13.98%～72.22%,平均增加了15.82%;使低产田犁底层和高产田耕层（10-20 cm）土壤w（ASOC）显著增加,中产田耕层土壤w（ASOC）显著降低。施肥使土壤w（LFOC）增加了-42.60%～168.57%,平均增加了48.83%;使中产田表层和犁底层、高产田表层和耕层土壤w（LFOC）显著增加,高产田犁底层土壤w（LFOC）显著降低。施肥使土壤w（DOC）增加了-42.74%～51.29%,平均增加了9.36%;使中产田耕层和犁底层、高产田表层和耕层土壤w（DOC）显著增加,低产田耕层土壤w（DOC）显著降低。施肥使土壤w（MBC）增加了-1.16%～19.97%,平均增加了9.32%,除中产田耕层土壤之外其他土层土壤w（MBC）均有所增加。施肥主要提高土壤ASOC和LFOC含量,促进土壤DOC的变化。施肥显著增加低产田土壤有机碳组分含量,促进中产田土壤有机碳组分变化,增加高产田土壤有机碳耗损。施肥主要增加表层（0-10 cm）土壤有机碳组分含量,耗损犁底层（20-40 cm）土壤有机碳,调解耕层（10-20 cm）土壤活性有机碳组分。施肥对微生物可利用性及结构不同的活性有机碳组分影响不同;高、中、低产田因其土壤理化性状及有机碳本底值不同,对施肥的响应存在差异。施肥总体增加土壤活性有机碳各组分含量,同时通过改变微生物及玉米根系活力影响活性有机碳含量及组分。土壤中有机碳组分与产量的回归方程为（产量）=-4 665.61-0.008×w（SOC）-0.421×w（ASOC）-0.777×w（LFOC）＋5.370×w（DOC）＋33.408×w（MBC）。ASOC和MBC具有土壤肥力指示作用,施肥主要通过调控土壤ASOC提高玉米产量。

This article selected the different fertility levels farmland soil planted spring maize （Zea mays ssp. mays L.） in Liaohe Irrigation for the study object. Through three consecutive years field experiment, the effects of fertilization on the constituents of soil organic carbon （TOC, ASOC, LFOC, DOC and MBC） were studied in different soil depths and the yield effect of soil organic carbon constituents were analyzed. The results indicated that consecutive planting spring maize significantly increased the w（TOC） in the low-yielding field, increased the w（ASOC） and w（MBC） and reduced the w（LFOC） in all types field soil, and the changes of w（DOC） was small. The fertilization made the w（TOC） increasing from -13.41% to 7.54%, by an average of 0.16%. It made the w（TOC） significantly increasing in the surface layer soil （0-10 cm） of high-yielding field, and made the w（TOC） significantly reducing in the plow ground floor soil （20-40 cm） of low-yielding field. The fertilization made the w（ASOC） increasing from -13.98% to 72.22%, by an average of 15.82%. It made the w（ASOC） significantly increasing in the plow ground floor soil of low-yielding field and in the plow layer soil （10-20 cm） of high-yielding field, and made the w（ASOC） significantly reducing in the plow layer soil of middie-yielding field. The fertilization made the w（LFOC） increasing from -42.60% to 168.57%, by an average of 48.83%. It made the w（LFOC） significantly increasing in the surface layer and plow ground floor soil of middle-yielding field and in the surface layer and plow layer soil of high-yielding field, and made the w（ASOC） significantly reducing in the plow ground floor soil of high-yielding field. The fertilization made the w（DOC） increasing from -42.74% to 51.29%, by an average of 9.36%. It made the w（DOC） significantly increasing in the plow layer and plow ground floor soil of middle-yielding field and in the surface layer and plow layer soil of high-yielding field, and made the w（DOC） significantly reducing in the plow layer soil of low-yielding field. The fertilization made the w（MBC） increasing from -1.16% to 19.97%, by an average of 9.32%. In addition to plow layer soil of middle -yielding field, the w（MBC） were increased. The fertilization mainly increased the contents of ASOC and LFOC, and promoted the changes of soil DOC. The fertilization significantly increased the contents of soil organic carbon （SOC） in low-yielding field, promoted the changes of SOC in middle-yielding field, and increased the depletion of SOC in high-yielding field. The fertilization mainly increased the contents of SOC in the surface layer soil, depleted the SOC in plow ground floor soil, and mediated the components of ASOC in plow layer soil. The fertilization influenced different on the bioavailabillty and the component of Asoc with different structures. The physical and chemical properties of soil and the background value of SOC were different for high, middle and low -yielding field, so that their reactions were very different to the fertilization. The fertilization overall increased the contents of each component of ASOC, and influenced the contents and components of ASOC through changing the microorganism and the activity of corn root. The regression equation of the SOC contents and ：yield was expressed as follow： yield =-4665.61-0.008×w（SOC）-0.421×w（ASOC）-0.777×w（LFOC）＋5.370×w（DOC）＋33.408×w（MBC）. The ASOC and MBC are provided with indicative function of soil fertility. The fertilization increased the yield of corn mainly by mediating contents of ASOC in soil.