Regulation of Growth and Seed Yield in Chia (Salvia hispanica L.) under Contrasting Soil Moisture Regimes

Abstract

As chia crop (Salvia hispanica L.) expands into new environments in Kenya, its response to moisture stress is only partially understood. This study simulated different soil moisture regimes to determine their effects on chia crop growth and yield, and to identify key traits that influence yield formation. Treatments comprised 40%, 60%, 80%, and 100% field capacity (FC). Watering soil to 40%, 60%, and 80% FC involved maintaining soil moisture at proportions equivalent to 0.40, 0.60, and 0.80 of the water content determined at field capacity, and irrigation was applied when approximately 50% of the assigned treatment moisture level had been depleted. Crop growth traits and yield components were maximized at 80% FC, with significant reductions observed at lower moisture levels, particularly 40% FC. However, in some instances, differences between crops grown under 80% and 100% FC were marginal. This suggests that moderate soil moisture levels may be sufficient in maximizing growth and yield of chia. The key determinants of chia seed yield were the number of panicles per plant and biomass production. These results imply that the introduction of chia into diverse agroecological zones in Kenya could consider not only rainfall amount and distribution patterns but also soil moisture retention capacity. Areas characterized by low rainfall, poor moisture retention, and heavy clay soils may be less suitable for chia production. However, field-based validation across agroecological zones is necessary in refining these recommendations.