Cotton Seedling Abrasion and Recovery from Wind Blown Sand

Abstract

Millions of hectares of crops are exposed to wind blown sand abrasion each year, and in many instances the damage is thought to be severe enough to require replanting. The goal of this study was to determine the effects of wind blown sand abrasion duration on cotton (Gossypium hirsutum L.) seedlings. Seedlings of three cotton cultivars were exposed to wind velocities of 13.4 m s−1 with sand abrasive flux density of 0.42 g cm−1 width s−1 for six treatment durations ranging from 0 to 40 min. Plants were destructively sampled at the time of the sand abrasion treatment and also at ≈2 and 4 wk after exposure. These three sampling dates provided two time intervals for assessing the amount of plant damage and regrowth using classical growth analysis. With increasing sand abrasion treatment time, leaf area and leaf, stem, and total shoot biomass were all reduced while final number of mainstem nodes increased (P ≤ 0.05). Cultivar differences in leaf mass were significant only at the second destructive sampling date (P ≤ 0.05). For the first harvest interval, between the first and second destructive sampling, shoot relative growth rate (RGR) and net assimilation rate (NAR) decreased with increasing sand abrasion treatment time. Regrowth during the second harvest interval revealed the opposite pattern, with RGR and NAR both increasing with increasing sand abrasion treatment time. In both harvest intervals, variation in RGR depended mainly on NAR rather than leaf area ratio (LAR). These results indicate that, despite near‐complete defoliation at the longest treatment duration of 40 min, cotton plants receiving this level of damage in the field may not require replanting.