Efeito da Aplicação da cobertura morta (mulch) e diferentes intervalos de rega no crescimento e rendimento da Acelga (Beta vulgaris var. Cicla) em solos salinos do Vale de Infulene

Abstract

Soil salinity refers to the excessive accumulation of soluble salts in the soil; when these reach high levels, they impair crop growth and degrade soil quality. The use of mulching is increasingly advocated to minimize salt stress conditions in horticultural practices. Furthermore, irrigation management plays a crucial role in salinity control, as it can facilitate the leaching of salts into deeper soil layers while maintaining adequate moisture levels for crop development. Thus, a trial was conducted to evaluate the effect of mulching and different irrigation intervals on the growth and yield of Swiss chard (Beta vulgaris var. cicla) in the saline soils of the Infulene Valley. The study took place in the KaMubukwana municipal district (Benfica neighborhood, Maputo City) between August and November 2025, at the fields of the "10 de Novembro" association. A randomized complete block design (RCBD) was used in a 2 × 3 factorial arrangement, comprising an irrigation factor with two levels—(i) daily irrigation and (ii) irrigation every other day—and a cultural practices factor with three levels: (i) local practice (chicken manure and daily irrigation), (ii) surface mulching, and (iii) incorporated straw. Four replications were used, totaling 24 plots. Parameters evaluated included the number of leaves, plant height, and yield. Soil salinity (EC) and pH were also assessed through weekly measurements using a portable COMBI 5000 device. Mulching application resulted in the highest number of leaves and yield for the Swiss chard (p<0.05). On the other hand, the application of mulch reduced the pH at the 20–40 cm depth from 9.7 to 8, while daily irrigation reduced the EC at the 0–20 cm depth from 4.4 to 0.6 dS m⁻¹; likewise, the interaction between daily irrigation and buried straw reduced the EC from 0.4 to 0.3 dS m⁻¹ at the 20–40 cm depth. This study supports recommending the use of mulch and buried straw in combination with daily irrigation for Swiss chard cultivation in saline-sodic soils.