Cooling Effect of Different Irrigation Methods in the Growth Stages of Chili Pepper (Capsicum frutescens L.)

Abstract

Sufficient application of water contributes to cooling of the soil and plant surroundings. In such context, this study investigated the cooling effect of different irrigation methods, using chili pepper as test crop, in its growth and yield performance. Drip, sprinkler, and furrow irrigation methods, applied at 7 a.m., 10 a.m., and 4 p.m. were evaluated. The cooling effect of irrigation method was evaluated in terms of canopy and soil temperature reduction. In addition, the plant growth and yield performance were also measured and analyzed. The canopy temperature reduction of 2.40 ºC, 2.21 ºC, and 1.88 ºC during the vegetative, flowering, and fruiting stages, respectively were obtained when water is applied at 4:00 p.m. using the sprinkler method. The significant reduction in canopy temperature which caused cooling effect by irrigation was attributed to the increased evaporation and relative humidity. Highest soil temperature reduction was achieved at 0.56 ?C using furrow irrigation. The significant change in furrow irrigation was caused by increased evaporation from the soil surface and the changes in the thermal conductivity and diffusivity of the soil. Plant height increase was highest using sprinkler irrigation which grew as high as 66.07 cm before the harvesting period. Stem diameter was bigger in furrow irrigated plants having a mean of 11.55 cm during the fruiting stage. Fruit yield was significantly highest (8.56 tons/ha) in sprinkler irrigation at 4:00 p.m. These results indicated that the cooling effect of irrigation contributes to growth and yield performance of chili pepper by delivering water through sprinkler irrigation method in the afternoon. These reported findings have practical implications for farm adaptation especially in high temperature environments. Finally, studies should be conducted by experimenting on crops belonging to different family to establish comparison.