Biomass and Rootstock Quality of Guava (Psidium guajava L.) Saline Water Irrigated under Nitrogen Fertilization

The increase in N concentration in the root zone of plants under saline conditions can inhibit the absorption of chloride and reduce the osmotic, toxic and nutritional effects caused by this ion. Thus, this study aimed to evaluate biomass and rootstock quality of guava. cv. Paluma irrigated with saline water under four N rates. The experiment was carried out in a greenhouse at the Center of Science and Agri-food Technology of the Federal University of Campina Grande (UFCG) at Pombal-PB, Brazil. The experimental design was randomized block with a 5 × 4 factorial arrangement. The treatments were levels of electrical conductivity of water - ECw (0.3. 1.1. 1.9. 2.7 and 3.5 dS m-1), with 70, 100, 130 and 160% of the N rate recommended for guava seedlings (541, 773, 1004.9 and 1236.8 mg N dm-3 of soil) and four replicates totaling 80 plots, each one with five plants. Salt stress caused by electrical conductivity of irrigation water of 1.4 dS m-1 onwards affected negatively the formation of phytomass of guava cv. Paluma rootstock, and this effect was mitigated on root dry matter and Dickson quality index by the increase in nitrogen rate up to 819.38 mg of N dm-3 of soil.