Excess moisture effects on the growth & yield of Spring Wheat
Canadian Agricultural Partnership funding
Curtis Cavers, AAFC Portage la Prairie
The current study was planned to see the effect of early and late flooding on four commonly grown wheat varieties in Manitoba. Plots were also grown under no flooding conditions as control for comparisons.
Continuous flooding at 2-3 leaf stage delayed wheat maturity and exhibited significant yield loss. Flooding at later crop stage did not have any effect on maturity, although it also reduced yield. Flooding at early crop stage produced nutrient deficiency symptoms in tested wheat varieties. Nutrient deficiency symptoms, however, were not so evident in plots of variety AAC Cameron. This might be a reason why this variety did not suffer yield loss up to the extent as seen in other three wheat varieties. These tests will be repeated next year again.
Wet soils cause an oxygen deficiency and reduction in nutrient uptake. Early flooding can significantly reduced tillering, plant height, delayed head emergence significantly affecting the grain yield. Excessive soil moisture also delays agronomic operations. The impact of these losses on farm net income is significant. During 1966-2015, excess moisture accounted for 38% of all crop losses in Manitoba (MASC).
Manitoba crop insurance data from 1965-1972 showed clay soils subjected to excess moisture in July experienced the highest yield loss (2-6 bu/ac/day) for barley, oats, wheat and flax crops (Rigaux and Singh,1977).
Additionally, farmers experience loss of nutrients due to extreme moisture as well as loss of soil. Excess water conditions may impact the ability of a plant to take up inorganic nutrients due to the effects on processes associated with solute movement across membranes (Barrett-Lennard 2003). Uptake of essential nutrients such as N, P, and K takes place against gradients of chemical and electrical potential, which requires energy inputs from aerobic respiration; respiration is inhibited under anaerobic conditions making nutrient uptake energetically unfavorable (Greenway and Gibbs 2003). For example, Huang et al. (1995) reported reduced concentrations of N, P, K, Mg, and Zn in wheat shoots under waterlogged conditions (and an increased concentration of these same elements in the wheat roots).