RESPONSE OF WATER STRESSED TOMATO PLANTS TO SOIL ORGANIC AMENDMENTS

Abstract

Two field trials were conducted during successive two summer seasons of 2019 and 2020 at the experimental farm, Fac. Environ. Agric. Sci., Arish Univ., North Sinai to investigate the influence of drought stress (100% ETc (D0), 85% ETc (DL), 75% ETc (DM) and 55% ETc (DH) and organic amendments (biochar, BCH and barley straw, ST) on soil water relation as well as growth, yield and quality of tomato. Biochar+barley straw treatment exhibited the highest increment under all water levels of the three water relation, i.e., field capacity (FC), plant permanent wilting point (PWP) and plant available water content (AWC) traits with no significant differences between biochar and biochar+barley straw treatments. The highest yielding treatments under high drought stress (55% ETc, DH) level were both BCH and BCH+ST treatments. As for stress tolerance indices, BCH+ST followed by BCH treatment recorded the highest RDI, STI, GMP, YI, DI, K1STI and K2STI suggesting more stress tolerance mechanism. Based on the yield category, treatments classified into three groups: high, moderate and low yield/feddan. Comparison between the two drought stress levels (DH and DM) shows the extent of improvement in the 75% ETc (DM). Construction of dendrogram based on 12 drought tolerance indices under non-stress and both high and moderate drought conditions were involved. Based on Fruit yield (ton/fed) under non-stress and high drought stress, the 4-amendment treatments split into two main clusters. Cluster I contained stress tolerant treatment that had low value of stress susceptibility (Biochar and Biochar+ST) indicating the best cluster for both growth conditions. Cluster II performed poorly in the reverse trend of tolerant-group. So, this study confirms the contribution of biochars to the sustainability of agriculture and water conservation.