Utilização de biocarvão e hidrogel e seu efeito na retenção hídrica do solo, no crescimento e na produtividade de cajueiro-anão clone “brs 226”

Abstract

The use of irrigation systems is the most commonly recommended strategy to supply the water requirement of plants in regions with ordinary or sporadic water deficit, however, because it requires a large investment in its implementation and maintenance, its use is limited among producers. Thus, looking for strategies that aim to reduce the applied water are always necessary. Based on these characteristics, the use of soil conditioners is an alternative with the potential to decrease the use of irrigation water, as they have a porous structure that increases the natural capacity of the soil to retain water. Thus, the aim of this study was to analyze the effect of two soil conditioners, biochar and hydrogel, on the growth, production and water retention variables of a dwarf cashew orchard “BRS 226” submitted to the rainfed regime. The experiment was carried out in the experimental field of Paraipaba, belonging to Embrapa - Agroindustria Tropical, Paraipaba - CE, using a randomized block design with four blocks and nine treatments. The biochar used was originated from cashew firewood and applied to the pits of the plants in doses of 0.5; 1.0; 2.0 and 4.0 kg pit-1. The hydrogel, on the other hand, used the polymer of the commercial name Hydroplan - EB®, in doses per pit of 20; 40; 60 and 80 g pit-1. The established dwarf cashew clone was the “BRS 226” with a spacing of four meters between plants and eight meters between lines. Two batteries of tensiometers were installed at depths of 0.15; 0.45 and 0.75 m of each treatment for monitoring soil moisture variation. Analyzes were carried out to determine the physical attributes of the soil, together with the making of a characteristic curve of water in the soil. The growth variables analyzed were plant height, stem diameter and crown diameter. For growth variables, average weight, production per plant and productivity of peduncles and nuts were analyzed. Water retention was monitored using daily data from tensiometers. The treatments that showed the highest water retention capacity in the soil were T1 and T7 respectively, 0.5 kg of biochar per pit and 60 g of water-retaining polymer per pit, although there was no statistical difference in the growth and growth variables. production of plants treated with conditioners.