Soil-plant system response to pulsed drip irrigation and salinity:: Bell pepper case study

High-frequency drip irrigation supplies water and nutrients at a rate that is close to plant uptake, thus enhancing growth and production. In light of water scarcity in and regions, marginal water is increasingly considered as a resource for agricultural production. The objective of this study was to investigate the combined effects of pulsed irrigation and water salinity on the response of the soil-plant system. As a test crop, bell pepper (Capsicum annuum L.) was cultivated in a screen-house and drip irrigated daily (D) and at high frequency (P) with saline (S) and fresh (F) water. Simultaneous monitoring of meteorological, physiological, soil physical, plant and soil chemical, and yield data was performed during the experiment. Most physiological parameters were negatively affected by high water salinity. No consistent effect of the irrigation frequency was found on the overall season, although pulsed irrigation led to higher plant weight and leaf area at the early stages of plant growth. The distinct patterns of soil water content for the two irrigation frequencies are presented. Salinity in the root zone was higher under pulsed irrigation, an observation that is supported by measured leaf chloride content and tensiometer readings indicating that the once daily application may have more efficiently removed salts from the top soil. Yield, fruit weight, and irrigation water use efficiency (IWUE) were highest under once daily irrigation with fresh water. High-frequency irrigation led to higher Mn concentrations in leaves and fruits and increased concentrations of Cl, N, and P in leaves, confirming earlier conclusions on improved P mobilization and uptake under pulsed irrigation.