Application of a modified irrigation method using compensated radiation integral, substrate moisture content, and electrical conductivity for soilless cultures of paprika

Irrigation strategy has a direct influence on the productivity and the production cost of soilless cultures of paprika, and thus more efficient irrigation methods are required. The objective of this study was to compare water use efficiency and crop productivity between a conventional irrigation method and a modified irrigation method using a precise irrigation control system. Accumulated radiation was used as an irrigation index for the conventional method as a control, whereas the compensated value of accumulated radiation as well as the substrate moisture content and electrical conductivity was used as irrigation indices for the modified one. Plant growth and water use efficiency were compared between both irrigation systems. The experiment was performed in a commercial farm cultivating paprika in Hwasung, Korea. For the modified method, the substrate moisture content was well-controlled in the range of 69-85% and showed a narrow fluctuation compared to the control. Additionally, the substrate electrical conductivity was maintained within 2.4-4.6 dS m−1 during the growth period, whereas the substrate electrical conductivity increased up to 7.9 dS m−1 for the control. Water consumption and water-use efficiency of the shoots and fruits were 6.6% and 3.7% higher, respectively, with the modified method compared to the control. Overall plant growth was better with the modified method. Based on these results, it could be concluded that the modified irrigation method improved the productivity of paprika in soilless cultures.