Scholarlink

<p>Nitrate stock in the vadose zone controls the timing and magnitude of its transfer from soils to groundwater and surface waters, thus acting as a key regulator of the global N cycle. This study evaluated how land-use conversion from natural vegetation to intensive cotton and jujube cultivation affected N surplus and nitrate dynamics in the vadose zone, surface water, and groundwater in the upper Tarim River. We established field-scale N balances by quantifying inputs and outputs. Concurrently, soil samples were collected from 108 representative plots (including 76 cotton fields, 27 jujube fields, and 5 natural vegetation areas), together with 105 surface water samples from the watershed and 98 groundwater samples. The annual N surpluses reached 270&#xa0;kg N ha⁻¹ for cotton and 355&#xa0;kg N ha⁻¹ for jujube, leading to corresponding annual nitrate accumulation rates of 174 and 240&#xa0;kg N ha⁻¹ yr⁻¹ in the 0–200&#xa0;cm soil profile. Despite a thick vadose zone that buffers the transfer of N from soils to groundwater, 14.0% of groundwater and 12.4% of surface water samples exceeded the World Health Organization drinking water standard (11.3&#xa0;mg N L⁻¹). N input and cultivation area were the primary positive drivers of nitrate storage, while irrigation rate exerted a negative control. These findings indicate that vadose zone nitrate storage represents the primary fate of surplus nitrogen following the conversion to intensive agriculture. Historical nitrate accumulation constitutes a legacy reservoir with long-term water quality implications, highlighting the urgent need for integrated nutrient and water management strategies to mitigate environmental risks in arid agricultural systems.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Excessive Nitrogen Surpluses from Land Conversion to Intensive Agriculture Drives Vadose Zone Nitrate Stock in Extremely Arid Northwestern China

  • 期刊论文

  • 发表日期：

    2026年6月2日

查看全文
  • Xinlu Bai,
  • Baoyue Zhang,
  • Sansan Song,
  • Mengjie Liu,
  • Weimo Wu,
  • Jianbin Zhou,
  • Jinhu Zhi

摘要

Nitrate stock in the vadose zone controls the timing and magnitude of its transfer from soils to groundwater and surface waters, thus acting as a key regulator of the global N cycle. This study evaluated how land-use conversion from natural vegetation to intensive cotton and jujube cultivation affected N surplus and nitrate dynamics in the vadose zone, surface water, and groundwater in the upper Tarim River. We established field-scale N balances by quantifying inputs and outputs. Concurrently, soil samples were collected from 108 representative plots (including 76 cotton fields, 27 jujube fields, and 5 natural vegetation areas), together with 105 surface water samples from the watershed and 98 groundwater samples. The annual N surpluses reached 270 kg N ha⁻¹ for cotton and 355 kg N ha⁻¹ for jujube, leading to corresponding annual nitrate accumulation rates of 174 and 240 kg N ha⁻¹ yr⁻¹ in the 0–200 cm soil profile. Despite a thick vadose zone that buffers the transfer of N from soils to groundwater, 14.0% of groundwater and 12.4% of surface water samples exceeded the World Health Organization drinking water standard (11.3 mg N L⁻¹). N input and cultivation area were the primary positive drivers of nitrate storage, while irrigation rate exerted a negative control. These findings indicate that vadose zone nitrate storage represents the primary fate of surplus nitrogen following the conversion to intensive agriculture. Historical nitrate accumulation constitutes a legacy reservoir with long-term water quality implications, highlighting the urgent need for integrated nutrient and water management strategies to mitigate environmental risks in arid agricultural systems.