Wind and Windblown Sand Damage to Pearl Millet

Abstract

Pearl millet [Pennisetum glaucum (L.) R. Br.] is grown worldwide in areas affected by wind erosion, but no data on associated damage to millet are available. Laboratory wind tunnel experiments were conducted to determine the kind and extent of damage to millet caused by wind, sandblasting, and burial. In Exp. 1, millet was exposed for 15 min to wind (8, 11, or 14 m s−1) or wind + sand (8.3, 25.0, or 41.7 g m−1 s−1 sand abrader flux) at 8 and/or 16 d after emergence (DAE). Viable leaf area, leaf net photosynthesis, and NO3 content were measured through 21 DAE and dry matter production through 57 DAE. In Exp. 2, millet was seeded as three single seeds or in tufts, exposed to 25 g m−1 s−1 sand flux for 15 min at the 1-, 2-, or 3-leaf stage, and then manually covered by 15 mm sand. Survival was monitored weekly; dry matter was determined 70 DAE. In Exp. 1, survival was uniformly 100%. Wind alone or low sand flux had no effect on viable leaf area. High sand flux decreased viable leaf area by 74% at 2 d after the 8-DAE exposure and 42% at 5 d after the 16-DAE exposure. Photosynthesis of the remaining leaf area was reduced up to 88% immediately after exposure compared with the control, and NO3 content of sandblasted millet was increased up to six times. Dry weight was reduced 40% at 21 DAE by the highest sand flux, but 9.7% at 57 DAE. In Exp. 2, burial decreased millet survival and dry weight. Buried tufts had a higher survival rate and 35% more dry weight than buried single plants. Millet buried at the 1-leaf stage had 28% higher survival than plants treated later. Sandblasting reduced dry matter of buried millet only. Regression analyses between calculated total kinetic effects and growth parameters showed low r2 values. Millet can survive short-term sandblasting at any growth stage, but growth is reduced by strong sand flux, a sequence of wind erosion events during early growth, or by combinations of abrasion with burial by blown sand

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