|TANAKA, DONALD - Retired ARS Employee|
Submitted to: Soil Science Society of America Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/9/2019
Publication Date: 9/5/2019
Citation: Halvorson, J.J., Archer, D.W., Liebig, M.A., Yeater, K.M., Tanaka, D.L. 2019. Impacts of intensified cropping systems on soil water use by spring wheat. Soil Science Society of America Journal. 83:1188-1199. https://doi.org/doi:10.2136/sssaj2018.09.0349.
Interpretive Summary: In semi-arid rainfed farming regions such as central North Dakota, effective use of water is critical. We measured soil water at various depths, and together with precipitation and yield data, determined the efficiency with which different crop sequences, under two tillage treatments, stored and used water. Soil water at planting and harvest was higher under no-till than minimum tillage for continuously grown spring wheat but not other crop sequences. Continuously cropped sequences stored more precipitation over the winter but had lower seasonal water use and average spring wheat yields compared to sequences with fallow. Water use efficiency was lower for spring wheat-fallow or continuous spring wheat compared to other sequences but continuous cropping resulted in markedly more efficient use of precipitation over the period of the study. These results are useful to producers in selecting crop sequences and tillage practices to best utilize precipitation in the northern Great Plains.
Technical Abstract: In semi-arid dryland farming regions such as central North Dakota, effective use of water is critical. As part of a long-term (1993-2011) study near Mandan, ND, we measured soil water at various depths, and together with precipitation and yield data, determined water use efficiency (WUE) and precipitation use efficiency (PUE) for spring wheat (Triticum aestivum L.) grown in different crop sequences under minimum (Min-till) or No-till. Root zone soil water (0-122 cm), measured at planting (SWP) and at harvest (SWH), varied as interaction between crop sequence and tillage. Under Min-till, lowest SWP was observed for intensified crop sequences, characterized by continuous cropping, but SWP was generally not impacted by intensification under No-till. Conversely SWH was unaffected by intensification under Min-till but highest for continuous spring wheat (CSW) under No-till. Tillage effects were evident for CSW where both SWP and SWH were significantly higher under No-till than Min-till. Intensification increased overwinter precipitation storage efficiency but also resulted in lower water use and grain yields, irrespective of tillage. Spring wheat WUE was highest for 3-phase sequences compared to either CSW or spring wheat-fallow. Continuous cropping resulted in lower WUE under Min-till but did not influence WUE under No-till. Continuous cropping also resulted in greater PUE over the period of the study. While crop sequence and tillage management can affect average WUE and PUE, the yield response to atypical annual or even intraseasonal patterns of precipitation and temperature may be of greater importance in the northern Great Plains.