Understanding water losses from irrigated pastures on loess-derived hillslopes
| Autor: | Peter C. Almond, Wei Hu, Channa Rajanayaka, C. Ghimire, S. Maley, G. Van Der Klei, M. Dodson, Nathan P. Arnold, Dirk Wallace, M.S. Srinivasan, R. Hayman, Steve Thomas, S. Langer, T. Johns, Mark S. George, Rogerio Cichota |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Hydrology
Irrigation geography geography.geographical_feature_category 0208 environmental biotechnology Soil Science 04 agricultural and veterinary sciences 02 engineering and technology Plant Science Pasture 020801 environmental engineering Water balance Loess 040103 agronomy & agriculture 0401 agriculture forestry and fisheries Environmental science Fragipan Surface runoff Agronomy and Crop Science Ecology Evolution Behavior and Systematics Nature and Landscape Conservation |
| Zdroj: | Journal of New Zealand Grasslands. 82:103-110 |
| ISSN: | 2463-2880 2463-2872 |
| Popis: | Irrigation is likely to increase water losses from hillslopes, particularly on loess-derived soils with impeded drainage. This is important as irrigation of these soils in New Zealand is increasing. A field site was established to measure runoff from a pasture hillslope irrigated by a centre-pivot in South Canterbury. Between November and March, 161 and 199 mm of irrigation was applied, with 23% more at the bottom of the slope. Runoff varied with position in the hillslope, with 3.5 times from the bottom plot (52 mm) compared to the top. Over the length of the slope (40 m) this represents a potential loss of 9% of precipitation, or 21% of the irrigation. Evidence for saturation excess and infiltration excess runoff was observed, with antecedent soil moisture conditions being a key factor. Pasture production and water use efficiency (WUE) also varied with slope, the least (4.6 t DM/ha or 12 kg DM/ha/mm) observed at middle and most at the top of the slope (10.1 t DM/ha or 23 kg DM/ha/mm). This was likely due to a combination of differences in radiation and soil conditions. There was indication that pasture growth was limited by water availability at the top and potentially excess at the bottom of the slope. Our results indicate potential for improving irrigation practices. |
| Databáze: | OpenAIRE |
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