| 紫色土丘陵区坡地柑橘园土壤碳氮的空间分布特征 |
| 摘要点击 652 全文点击 209 投稿时间：2023-02-03 修订日期：2023-03-12 |
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| 中文关键词 紫色土 柑橘园 坡位 氮（N） 碳（C） 空间分布 |
| 英文关键词 purple soil citrus orchards slope position soil nitrogen （N） soil carbon （C） spatial variation |
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| 中文摘要 |
| 20世纪90年代以来,西南紫色土丘陵区大量坡耕地转变为果园,提高了农民的经济收益,但这一土地利用变化对土壤碳（C）、氮（N）空间分布特征的影响仍然缺乏研究.为探究紫色土丘陵区坡耕地转变为果园后土壤C、N的空间分布特征,选取四川盆地中部紫色土丘陵区代表性柑橘园为研究对象,分析了由坡耕地转变为柑橘园后,土壤C、N空间分布特征及其主要影响因素.结果表明,坡面位置（坡位）对土壤总氮（TN）、硝态氮（NO3--N）和可溶性有机碳（DOC）含量均有显著影响（P<0.05）,而对土壤总有机碳（SOC）和铵态氮（NH4+-N）的含量没有显著影响（P>0.05）.在0~30 cm土层,土壤NO3--N含量沿坡面的变化趋势为：上坡位<中坡位<下坡位,而TN和DOC含量沿坡面的变化趋势为：上坡位>中坡位>下坡位.各坡位土壤C、N含量随深度（0~30 cm）增加呈现整体降低趋势,其中土层深度对土壤TN、SOC、NO3--N和DOC含量的影响显著（P<0.05）.坡面土壤TN储量（0~30 cm）随坡位自上而下逐渐降低（P<0.05）,其中坡上、坡中和坡下的土壤TN储量分别为2.37、1.89和1.62 t·hm-2（以N计）.SOC储量沿坡面的分布差异不显著,变化范围（以C计）为56.12~58.48 t·hm-2,整个坡面土壤TN与SOC的储量呈显著正相关关系.结果表明,在预测土壤C、N含量及储量对土地利用转变响应时不能忽视土壤养分的空间分布规律,研究可为理解紫色土丘陵区耕地转变为果园后土壤C、N空间分布特征及主控因子提供研究案例. |
| 英文摘要 |
| Since the 1990s, a large area of sloping farmland in a purple soil hilly region of southwest China was converted into an orchard to prevent soil erosion, increase soil fertility, and elevate economic benefits for farmers. In order to explore the spatial distribution of soil carbon (C) and nitrogen (N) fractions on the slope of returning arable lands to citrus orchards in purple soil hilly areas, a soil sampling event was carried out in a citrus orchard at the Yanting Agro-ecological Experimental Station of Purple Soil, Chinese Academy of Sciences, to examine the differences in soil C and N fractions and their influencing factors. The results showed that the slope position had significant effects on the contents of soil total nitrogen (TN), nitrate nitrogen (NO3--N), and dissolved organic carbon (DOC) (P < 0.05), but the effects were not obvious regarding the total organic carbon (SOC) and ammonia nitrogen (NH4+-N) of the soil (P > 0.05). For topsoil (0-30 cm), the variation trend of soil NO3--N content along the slope was upper slope < middle slope < lower slope, whereas the TN and DOC contents along the slope exhibited the trend of upper slope > middle slope > lower slope. The contents of soil C and N in each slope position generally showed a downward trend with increasing soil depth (0-30 cm). The contents of soil TN, SOC, NO3--N, and DOC were significantly affected by soil depth (P < 0.05). The TN storage (0-30 cm) significantly decreased from the top to the bottom within the soil slope, with a value of 2.37, 1.89, and 1.62 t·hm-2 (reported as N) for the upper slope, middle slope, and lower slope, respectively. There was no significant difference in SOC reserves along the slope, with a range from 56.12 to 58.48 t·hm-2 (reported as C). Our results provide scientific basis for understanding the spatial distribution of soil nutrients of the restored farmland in purple soil hilly areas. Our research suggests that the spatial distribution of soil carbon and nitrogen storage should not be ignored when predicting the response of soil nutrients to land use change. |
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