Water use and root growth by annual and perennial pastures and subsequent crops in a phase rotation

Autor: S.F Micin, P. R. Ward, F. X. Dunin
Rok vydání: 2002
Předmět:
Zdroj: ResearcherID
ISSN: 0378-3774
DOI: 10.1016/s0378-3774(01)00157-3
Popis: Perennial pastures and trees have been proposed as a means of increasing water use, reducing groundwater recharge, and therefore reducing the spread of secondary salinity in southern Australia. This paper investigates comparative water use throughout a 5-year rotation involving 3 years of pasture (either annual subterranean clover ( Trifolium subterraneum L.) or perennial lucerne ( Medicago sativa L.)) followed by wheat ( Triticum aestivum L.) and then by canola ( Brassica napus L.). Within the pasture phase, lucerne reduced soil water content during summer and autumn by approximately 60 mm more than the annual pasture. Lucerne in its second year produced 1.7 times more root biomass than the annual pasture, and also grew roots deeper into the soil. Wheat after lucerne produced 15 t ha −1 dry matter compared with 8 t ha −1 for wheat after clover, but grain yields were similar due to a combination of frost damage and water stress. There was a small difference in canola dry matter production, but no differences in canola grain yield or 1000-grain weight in the second year after pasture. Canola root distributions were similar on the two blocks. Average annual water leakage was 45 mm for the annual pasture–wheat–canola rotation and 17 mm for the lucerne pasture–wheat–canola rotation. Wheat after lucerne extracted 20 mm more water from the ‘B’ horizon than wheat after clover, and this extended the period of protection against water leakage. Water leakage under the lucerne block commenced before the dry soil buffer was completely refilled, indicating the possibility of bypass flow.
Databáze: OpenAIRE
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