Hypoxic stress in the root zone of pea (Pisum sativum L.) under different suboptimal water regimes and soil cover systems and impact on growth

Abstract

Hypoxia stress in plants due to excess water limits agricultural productivity in crops such as peas (Pisum sativum L.), affecting physiological processes such as root respiration and photosynthesis. With the need to optimize water use in agriculture, this study evaluated the effect of different levels of water saturation in the root zone (25 %, 50 %, 75 % and 100 %) on pea growth, comparing systems with cover (closed) and without cover (open) on hypoxic stress and water efficiency.  The study was conducted in Viacha La Paz, Bolivia (3,857 m a.s.l.), in 2019. Variables (height, stem diameter, leaf area, IAF, TCA, TCR, TAN and water consumption) were measured under two systems. Destructive sampling was carried out monthly for 126 days. The 75 % saturation treatment in a closed system showed the best results in height (79.70 cm), leaf area (545 cm²), IAF (1.0265) and TAN (0.0023 g/cm² day). In the open system, the same level stood out in TCA (1.0179 g/day) and TCR (0.1475 g/g day). The open systems with 75 % and 100 % saturation registered higher water consumption (12,860.63 cm³ and 12,583.60 cm³), while the closed systems with 100 % and 75 % consumed less water (9,089.10 cm³ and 8,781.00 cm³). The 75% saturation level in the closed system optimized pea growth and reduced water consumption, proving to be an efficient strategy for crops under conditions of water limitation, minimizing hypoxic stress without compromising productivity.