Determination of the Permanent Wilting Point of Physalis peruviana L.

Abstract

The soil–water potential limit, or permanent wilting point (PWP), of Physalis peruviana L. is not known. Thus, determining the PWP of P. peruviana in different soils is essential to plan crops and manage irrigation in order to optimize the use of water and electricity. The objective of this study was to determine the PWP for P. peruviana in sandy and sandy clay loam soils. In a greenhouse, P. peruviana plants were grown in pots with different types of soil and maintained at 80% of field capacity. At intervals of 10 days, the irrigation of three pots was stopped, and when the plants wilted, they were transferred to a dark chamber without a vapor pressure deficit to verify if they would return to turgidity. When turgidity was not recovered, the PWP was considered, and the soil matric potential was determined by the water retention curve method. In sandy soil, P. peruviana wilted, on average, 1.7 days faster than in sandy clay loam soil. Regardless of the soil, matric potential equivalent to PWP decreased throughout the P. peruviana crop cycle. For sandy soil, the matric potential equivalent to PWP of P. peruviana ranges from −180 kPa (equivalent to 12% of the estimated value with a moisture release curve) to −2266 kPa (151% of the estimated value). In sandy clay loam soil, this matric potential ranges from −665 kPa (44% of the estimated value) to −1611 kPa (107% of the estimated value). The results contribute to water management and calculation of available water for P. peruviana; however, different soil textures do not have a single matric potential equivalent to PWP.