中文关键词土壤呼吸自养呼吸异养呼吸氮磷添加温度敏感性 英文关键词soil respirationautotrophic respirationheterotrophic respirationN and P additiontemperature sensitivity

作者	单位	E-mail
周俊杰	西北农林科技大学水土保持研究所, 黄土高原土壤侵蚀与旱地农业国家重点实验室, 杨凌 712100	zjj9598@126.com
陈志飞	西北农林科技大学水土保持研究所, 黄土高原土壤侵蚀与旱地农业国家重点实验室, 杨凌 712100
杨全	中国科学院水利部水土保持研究所, 杨凌 712100
赖帅彬	西北农林科技大学水土保持研究所, 黄土高原土壤侵蚀与旱地农业国家重点实验室, 杨凌 712100
王智	西北农林科技大学水土保持研究所, 黄土高原土壤侵蚀与旱地农业国家重点实验室, 杨凌 712100 中国科学院水利部水土保持研究所, 杨凌 712100
徐炳成	西北农林科技大学水土保持研究所, 黄土高原土壤侵蚀与旱地农业国家重点实验室, 杨凌 712100 中国科学院水利部水土保持研究所, 杨凌 712100	Bcxu@ms.iswc.ac.cn

中文摘要 为探究不同氮磷添加水平对黄土丘陵区退耕草地土壤呼吸及其组分的影响，于2018年5~9月采用田间试验的方法，设置3个施氮（以N计）主区[0、50和100 kg·（hm²·a）^-1]和3个施磷（以P₂O₅计）副区[0、40和80 kg·（hm²·a）^-1].测定每月各处理下土壤总呼吸和异养呼吸速率，以及土壤温度和土壤含水量.结果表明，氮磷添加对土壤温度和土壤水分的影响均不显著（P>0.05）.土壤呼吸速率具明显月份变化特征，在7月达到峰值.未施肥处理的月平均土壤总呼吸、异养呼吸和自养呼吸分别为0.69、0.39和0.29 g·（m²·h）^-1.未施氮条件下，施磷对土壤呼吸及其组分无显著影响（P >0.05）.施氮条件下，磷添加显著提高土壤呼吸及其组分的呼吸速率（P<0.05），氮磷配施后月平均土壤总呼吸、异养呼吸和自养呼吸最大值分别为0.93、0.50和0.47 g·（m²·h）^-1.未施肥的土壤总呼吸、异养呼吸和自养呼吸的Q₁₀值分别为1.86、2.36和2.24；氮磷添加降低了土壤呼吸及其组分的Q₁₀值.总体上，氮磷添加对黄土丘陵区退耕草地土壤呼吸及其组分的影响与施氮磷量有关. 英文摘要 Understanding the soil respiration characteristics in response to nitrogen and phosphorus addition in farming-withdrawn grasslands within semi-arid loess hilly-gully regions is of great importance for providing a theoretical basis for evaluating the effects of artificial regulation approaches on carbon cycling. We report on a field experiment that was undertaken from May to September 2018 in a farming-withdrawn grassland ecosystem in China, which is dominated by Stipa bungeana and Lespedeza davurica. Three different levels of nitrogen and phosphorus additions were used, including three main plots of N[0, 50, and 100 kg·(hm²·a)^-1] and three subplots of P (P₂O₅)[0,40, and 80 kg·(hm²·a)^-1]. The soil respiration rate, heterotrophic respiration rate, soil temperature, and soil moisture were measured monthly in each treatment. Results showed that N and P addition had no effect on soil temperature or moisture content (P>0.05). The soil respiration rate showed an obvious monthly variation and peaked in July. In the treatment without fertilizer addition, the monthly mean soil respiration rate, heterotrophic respiration rate, and autotrophic respiration rate were 0.69, 0.39, and 0.29 g·(m²·h)^-1, respectively. P addition had no significant effect on the soil respiration rate and its components without N addition (P>0.05). Under conditions of N addition, P addition significantly increased the soil respiration rate and its component (P<0.05). The monthly mean soil respiration rate, heterotrophic respiration rate, and autotrophic respiration rate were 0.93, 0.50, and 0.47 g·(m²·h)^-1, respectively. The Q₁₀ (i.e., temperature sensitivity) values for soil respiration, heterotrophic respiration, and autotrophic respiration in unfertilized soil were 1.86, 2.36, and 2.24, respectively. The addition of N and P reduced the Q₁₀ value of soil respiration and its components. Our findings suggest that the response of soil respiration and its two components to N and P addition in studied farming-withdrawn grassland in the semiarid loess hilly-gully region were closely related to their addition amounts.

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