Water use efficiency and yield of cotton under deficit irrigation and mulching practices

Abstract:

Here is a paradox that cotton growers in temperate Europe face: the crop demands 700-1300 mm of water to complete its cycle, yet the regions experimenting with cotton cultivation receive less than 650 mm of summer rainfall. This research examined four deficit irrigation levels (100%, 80%, 60%, 40% ETc) combined with four mulch types (none, wheat straw, black polythene, biodegradable film) in a factorial randomized block design on cotton variety Sicala V-2 at the Midlands Institute of Agriculture and Food, Nottingham, UK, during summer 2023. Black polythene mulch at 80% ETc achieved the best balance: seed cotton yield of 2134 kg/ha (88% of full irrigation without mulch), water use efficiency of 8.14 kg/m³ (+67% over unmulched full irrigation), and B:C ratio of 2.87. Severe deficit (40% ETc) raised WUE to 11.83 kg/m³ but depressed yield to 1487 kg/ha. Mulching reduced soil evaporation by 28-41% depending on material. These findings support 80% ETc with black polythene mulch as the recommended deficit irrigation strategy for cotton in water-limited UK trial conditions.