长期施氮引起的黄土高原旱地土壤不同形态碳变化

doi:10.3864/j.issn.0578-1752.2014.14.010

摘要/Abstract

摘要： 【目的】提高土壤碳固持，特别是增加有机碳累积、减少碳损失，对于提高旱地土壤肥力、缓解大气温室效应具有重要意义。黄土高原旱地土壤有机碳含量低，增施氮肥是这一地区重要的作物增产措施，但氮肥投入对土壤碳的影响如何，一直没有报道。【方法】利用黄土高原旱地持续23年的长期定位试验，在每年施磷39 kg P2O5•hm-2条件下，设置0、45、90、135、180 kg N•hm-2 5个氮水平种植冬小麦，在小麦收获期采集0—40 cm不同土层的土壤样品，研究长期施用不同用量的氮肥对旱地土壤总碳、有机碳、轻质有机碳及无机碳的影响，分析不同氮肥用量引起的土壤有机碳、轻质有机碳及无机碳累积量的变化，定量分析氮肥用量对旱地土壤不同形态碳的影响。【结果】随氮肥用量增加，旱地土壤不同土层总碳无显著变化，但0—30 cm土层有机碳含量却随之增加，与不施氮肥相比，增幅可达7%—28%；0—40 cm土层轻质有机碳含量也增加，增幅达31%—106%，但施氮量过高不利于有机碳累积。对不同形态土壤碳累积量与氮肥用量的回归分析表明，施氮量120 kg N•hm-2时，0—30 cm土层有机碳累积量达最高值36.6 Mg；施氮量161 kg N•hm-2时，0—40 cm土层轻质有机碳累积量达最高值2.69 Mg；每千克肥料氮每年可使土壤有机碳增加1.34 kg•hm-2，轻质有机碳增加0.31 kg•hm-2；0—20 cm表层土壤轻质有机碳占有机碳的百分比也随施氮量增加而升高。相反，5—20 cm土层土壤无机碳含量却随氮肥用量增加而显著降低，施氮量180 kg N•hm-2时，无机碳累积量比不施氮减少2.8 Mg，每千克肥料氮每年可使无机碳减少0.67 kg•hm-2。【结论】在黄土高原旱地长期施用不同用量的氮肥虽不显著影响土壤的总碳数量，却显著地改变了旱地土壤碳的组成，即通过增加土壤的轻质有机碳，增加了土壤的有机碳累积量，同时降低了土壤的无机碳累积。因此，合理调控氮肥用量，不仅是旱地作物增产的关键措施，对增加土壤有机碳固持、培肥土壤也有重要意义。同时，施用氮肥引起的土壤无机碳损失不容忽视，其潜在的农业、生态与环境效应需引起大众关注。

关键词: 土壤 , 氮肥用量 , 有机碳 , 无机碳 , 轻质有机碳

Abstract: 【Objective】 Increased organic carbon (C) sequestration, especially the accumulation of organic C in soil, and decreased carbon losses from soil are of great importance for improving the dryland soil fertility and mitigating the greenhouse effect. Soils in the Loess Plateau areas are known typically lower in contents of organic C, and increasing application of nitrogen (N) fertilizer is proved to be the important tactical measure to increase crop yields, but information about how the N fertilizer input can affect the soil C is still lacking. 【Method】 A 23 years long-term experiment was conducted with winter wheat as test crop growing at five N rates of 0, 45, 90, 135, 180 kg N•hm-2 per year on a basal fertilization of 39 kg P2O5•hm-2 per year in dryland area of Loess Plateau. Soil samples were collected from 0 to 40 cm soil layers for each plots at harvest of winter wheat, in order to study the effects of long-term application of different nitrogen fertilizer rates on soil total carbon (TC), total organic carbon (TOC), light fraction organic carbon (LFOC) and inorganic carbon (IC), estimate the changes of TOC, LFOC and IC accumulation, and quantify the effects of N fertilizer application rates on different kinds of C in dryland soil. 【Result】 Obtained results showed that, with the increase of N fertilizer rates, the TC showed no significant change, while the TOC contents in 0 to 30 cm soil layers were increased by 7% to 28%, and the LFOC contents in 0-40 cm soil were increased by 31% to 106 %, but over application of N fertilizer showed no advantages on the organic carbon accumulation. Analysis of regression with the accumulation of different soil C fractions to N fertilizer application rates showed that, TOC accumulation in 0 to 30 cm soil layers reached the maximum of 36.6 Mg at 120 kg N•hm-2 and LFOC in 0 to 40 soil layers reached the maximum of 2.69 Mg at 161 kg N•hm-2, with the application of 1.0 kg fertilizer N per year led to an increase of TOC by 1.34 kg•hm-2 and LFOC by 0.31 kg•hm-2. In addition, the ratio of LFOC to TOC in 0 to 20 cm soil layers was found also increased with the increase of N fertilizer rate. In contrast, the IC content decreased significantly with the increase of N fertilizer application rates, especially in the 5 to 20 cm soil layers, where accumulation of IC was found decreased by 2.8 Mg at 180 kg N•hm-2, with the application of 1.0 kg fertilizer N per year led to a decrease of IC by 0.67 kg•hm-2. 【Conclusion】 Long term application of different rates of N fertilizer showed no significant effects on the amount of TC, but the composition of different C fraction was remarkably changed in the dryland soil of the Loess Plateau, with the accumulation of TOC increased due to increase of LFOC sequestration in soil, but the IC accumulation decreased. Therefore, rational application of N fertilizer is not only the key measure to increase the crop yield, but is also of great importance to increase the organic carbon sequestration and then the soil fertility. However, the loss of inorganic carbon from soil caused by application of N fertilizer should not be overlooked, and sufficient attentions and concerns should be paid to the effects from the losses of soil IC on the sustainability of agriculture, ecology and environment in this area.

Key words: soil , N fertilizer rate , total carbon , organic carbon , inorganic carbon , light fraction of organic carbon

李小涵1, 2, 李富翠1, 刘金山1, 2, 郝明德3, 王朝辉1, 2. 长期施氮引起的黄土高原旱地土壤不同形态碳变化[J]. 中国农业科学, 2014, 47(14): 2795-2803.

LI Xiao-Han-1, 2 , LI Fu-Cui-1, LIU Jin-Shan-1, 2 , HAO Ming-De-3, WANG Chao-Hui-1, 2 . Changes of Different Carbon Fractions Caused by Long-Term N Fertilization in Dryland Soil of the Loess Plateau[J]. Scientia Agricultura Sinica, 2014, 47(14): 2795-2803.

0
/ / 推荐

导出引用管理器 EndNote|Reference Manager|ProCite|BibTeX|RefWorks

链接本文: https://www.chinaagrisci.com/CN/10.3864/j.issn.0578-1752.2014.14.010

https://www.chinaagrisci.com/CN/Y2014/V47/I14/2795

参考文献

[1]Lal R. Carbon management in agricultural soils. Mitigation and Adaptation Strategies for Global Change，2007, 12(2): 303-322.

[2]黄耀, 孙文娟. 近20年来中国大陆农田表土有机碳含量的变化趋势. 科学通报, 2006, 51(7): 750-763.

Huang Y, Sun W J. Changes of organic carbon content in topsoil of cropland in recent 20 years in the mainland of China. Chinese Science Bulletin, 2006, 51(7): 750-763. (in Chinese)

[3]杨景成, 韩兴国, 黄建辉. 土壤有机质对农田管理措施的动态响应. 生态学报, 2003, 23(4): 787-796.

Yang J C, Han X G, Huang J H. The dynamics of soil organic matter in cropland responding to agricultural practices. Acta Ecologica Sinica, 2003, 23(4): 787-796. (in Chinese)

[4]Guo J H, Liu X J, Zhang Y, Shen J L, Han W X, Zhang W F, Christie P, Goulding K W T, Vitousek P M, Zhang F S. Significant acidification in major Chinese croplands. Science, 2010, 327(5968): 1008-1010.

[5]Ayoub A T. Fertilizers and the environment. Nutrient Cycling in Agroecosystems, 1999, 55(2): 117-121.

[6]Shauna M, Robert G, Richard B. Effects of increased atmospheric CO2, temperature, and soil N availability on root exudation of dissolved organic carbon by a N-fixing tree (Robinia pseudoacacia L). Plant and Soil, 2000, 222(1/2): 191-202.

[7]Sharrow S H, Ismail S. Carbon and nitrogen storage in agroforests, tree plantations, and pastures in western Oregon, USA. Agroforestry Systems, 2004, 60(2): 123-130.

[8]李小涵, 王朝辉, 郝明德李生秀. 黄土高原旱地不同种植模式土壤碳特征评价. 农业工程学报, 2010, 26(S2): 325-330.

Li X H , Wang Z H, Hao M D, Li S X. Evaluation on soil carbon contents under different cropping systems on dryland in Loess Plateau. Transactions of the CSAE, 2010, 26(S2): 325-330. (in Chinese)

[9]郝明德, 王旭刚, 党廷辉, 李丽霞, 高长青. 黄土高原旱地小麦多年定位施用化肥的产量效应分析. 作物学报, 2004, 30(11): 1108-1112.

Hao M D, Wang X G, Dang T H, Li L X, Gao C Q. Analysis of Long-term Fertilization Effect on Yield of Wheat in Dry - land on Loess Plateau. Acta Agronomica Sinica, 2004, 30(11): 1108-1112. (in Chinese)

[10]郭胜利, 高会议, 党廷辉. 施氮水平对黄土旱塬区小麦产量和土壤有机碳、氮的影响. 植物营养与肥料学报, 2009, 15(4): 808-814.

Guo S L, Gao H Y, Dang T H. Effects of nitrogen application rates on grain yield, soil organic carbon and nitrogen under a rainfed cropping system in the loess tablelands of China. Plant Nutriti on and Fertilizer Science, 2009, 15(4): 808-814. (in Chinese)

[11]Haynes R J. Labile organic matter fractions as central components of the quality of agricultural soils: an overview. Advances in Agronomy, 2005, 85: 222-269. (in Chinese)

[12]谢驾阳, 王朝辉, 李生秀. 施氮对不同栽培模式旱地土壤有机碳氮和供氮能力的影响. 西北农林科技大学学报: 自然科学版, 2009, 37(11): 187-192, 200.

Xie J Y, Wang Z H, Li S X. Effects of nitrogen fertilizer application on soil organic carbon and nitrogen accumulation and mineralization under different cultivations in northwest dryland. Journal of Northwest A &F University: Natural Science Edition, 2009, 37(11): 187-192, 200. (in Chinese)

[13]王玲莉, 娄翼来, 石元亮, 韩晓日. 长期施肥对土壤活性有机碳指标的影响. 土壤通报, 2008, 39(4): 752-755.

Wang L L, Lou Y L, Shi Y L, Han X R. Long-term fertilization on indicators of soil active organic carbon. Chinese Journal of Soil Science, 2008, 39(4): 752-755. (in Chinese)

[14]Bremer E, Janzen H H, Johnston A M. Sensitivity of total, light and mineralizable organic matter to management practices in a Lethbridge soil. Canadian Journal of Soil Science, 1994, 74 (2): 131-138.

[15]Hassink J, Whitmore A P, Kubát J. Size and density fractionation of soil organic matter and the physical capacity of soils to protect organic matter. Developments in Crop Science, 1997, 25: 245-255.

[16]Campbell C A, Selles F, Lafond G P, Biederbeck V O, Zentner R P. Tillage-fertilizer changes: effect on some soil quality attributes under long-term crop rotations in a thin Black Chernozem. Canadian Journal of Soil Science, 2001, 81(2): 157-165.

[17]潘根兴. 中国土壤有机碳和无机碳库量研究. 科技通报, 1999, 15(5): 330-332.

Pan G X . Study on Carbon Reservoir in Soils of China. Bulletin of Science and Technology, 1999, 15(5): 330-332. (in Chinese)

[18]Li G T, Zhang C L, Zhang H J. Soil inorganic carbon pool changed in long-term fertilization experiments in north China plain. Proceedings of the 19th World Congress of Soil Science: Soil solutions for a changing world, Brisbane, Australia, 1-6 August 2010. International Union of Soil Sciences (IUSS), c/o Institut für Bodenforschung, Universität für Bodenkultur.

[19]马元喜. 不同土壤对小麦根系生长动态的研究. 作物学报, 1987, 13(1): 37-44.

Ma Y X. A study on growing dynamic of wheat root system in various soils. Acta Agronomica Sinica, 1987, 13(1): 37-44. (in Chinese)

[20]邱新强, 高阳, 黄玲, 李新强, 孙景生, 段爱旺. 冬小麦根系形态性状及分布. 中国农业科学, 2013, 46(11): 2211-2219.

Qiu X Q, Gao Y, Huang L, Li X Q, Sun J Sh , Duan Ai-Wang. Temporal and spatial distribution of root morphology of winter wheat. Scientia Agricultura Sinica, 2013, 46(11): 2211-2219. (in Chinese)

[21]孟红旗, 刘景, 徐明岗, 吕家珑, 周宝库, 彭畅, 石孝君, 黄庆海. 长期施肥下我国典型农田耕层土壤pH演变. 土壤学报, 2013, 50(6): 1109-1116.

Meng H Q, Liu J, Xu M G, Lü J L, Zhou B K, Peng Ch, Shi X J, Huang Q H. Evolution of pH in topsoils of typical Chinese croplands under long-term fertilization. Acta Pedologica Sinica, 2013, 50(6): 1109-1116. (in Chinese)