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Land‐use change from cropland to orchard leads to high nitrate accumulation in the soils of a small catchment

Gao, Jingbo; Lu, Yongli; Chen, Zhujun; Wang, Lei; Zhou, Jianbin. 2019 Land‐use change from cropland to orchard leads to high nitrate accumulation in the soils of a small catchment. Land Degradation & Development. https://doi.org/10.1002/ldr.3412

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Abstract/Summary

Land‐use change from cereals to fruit orchards usually results in a high nutrient surplus in soil. The excessive accumulation of nitrogen (N) in soil, mainly as nitrate, leached from the root zone may serve as a long‐term source of surface or groundwater pollution. The N balances and nitrate accumulation in the soil profiles of cereal fields and kiwifruit orchards in the Yujiahe catchment, Shaanxi, China, were compared. Excessive N fertilisation resulted in an excessive N surplus (1,133 kg N ha−1 yr−1) in orchards (8‐times higher than that in cereal fields). More than 77.5% of nitrate in the soil profile (0–400 cm) of the orchards was below a soil depth of 100 cm. The average accumulated nitrate within a profile 0–400 cm of orchards was 3,288 kg N ha−1, which was 16‐fold higher than that of cereal fields. The accumulated nitrate in soil profiles on the downslope (5,959 kg N ha−1) was approximately 2 times higher than that of the upslope in the same sloping orchards. The accumulated nitrate in soil profiles at the lowland zone of the catchment was higher than that of the upland zone. Excessive nitrate moves not only vertically downwards to deeper soil depth but also laterally into lower elevations at both field and catchment scales. The total stored nitrate in the upper soil profile of 400 cm in the catchment was 464.8 Mg N, whereas 94.8% (440.8 Mg N) was in orchards. Thus, changing land use from cereal crops to orchards leads to a high nitrate accumulation in the catchment.

Item Type: Publication - Article
Digital Object Identifier (DOI): https://doi.org/10.1002/ldr.3412
ISSN: 1085-3278
Additional Keywords: GroundwaterBGS, Groundwater, Environmental change, Nitrate pollution
Date made live: 11 Sep 2019 10:54 +0 (UTC)
URI: http://nora.nerc.ac.uk/id/eprint/525065

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