Allan Cunha Barros

Características químicas e salino-sodicidade dos solos do Perímetro Irrigado Califórnia, SE, Brasil

The improper irrigation management may result in the accumulation of salts in the soil profile, which intensity depends on the irrigation water quality, the leaching fraction adopted and on the evapotranspiration demand of the region. The objective of the present study was to study the physical and chemical characteristics of the soils in the irrigated district of California, located in the northwest of the State of Sergipe. Thus, soil sampling were made in 54 lots, corresponding to 16.4% of the lots of this district. The highest salt and sodium concentrations occurred in the shallowest soil layer (0-0.2m), evidencing the lack of an appropriate irrigation management in order to control the salinity build up. The increasing of the soil pH was significantly correlated to the exchangeable sodium percentage, reaching values over 9.5. Significant positive correlations were observed between the electrical conductivity and the Ca and Mg content, indicating that salts of both ions could be accumulating in soil by the capillary rise of the water table, associated to the lack of leaching and drainage.

Sais fertilizantes e manejo da fertirrigação na produção de tomateiro cultivado em ambiente protegido

Avaliou-se o efeito da aplicacao em excesso de fertilizantes via irrigacao em solos com diferentes niveis de salinidade, sobre as variaveis produtivas do tomateiro em ambiente protegido localizado no Departamento de Engenharia de Biossistemas da ESALQ/USP, Piracicaba-SP. O delineamento estatistico foi o em blocos casualizados em esquema fatorial 6x2 com quatro repeticoes, em que os fatores consistiram em seis niveis iniciais de salinidade do solo (S1 = 1,62; S2 = 2,40; S3 = 2,98; S4 = 3,48; S5 = 4,63 e S6 = 5,82 dS m-1) e em dois manejos da fertirrigacao (M1 - Adubos aplicados em fertirrigacao obedecendo a curva de absorcao de nutrientes da cultura e M2 - Cultivo sem aplicacao de fertilizantes via agua de irrigacao). As variaveis fitomassa fresca de frutos e numero de frutos foram afetadas estatisticamente, tanto pelo manejo quanto pela salinidade do solo com reducoes de 38,82 e 27,31 % para o manejo M1. A interacao entre (salinidade x manejo) e a salinidade isolada influenciou significativamente os componentes estudados, exceto para fitomassa seca do caule e raiz na interacao. O manejo M1 foi superior em todos os componentes de producao estudados quando comparado ao manejo M2. O limiar para a cultivar foi superior ao encontrado na literatura.

Lisímetro de pesagem de grande porte. Parte II: consumo hídrico do coqueiro anão verde irrigado

This paper, as Part II of a research carried out in Sergipe state, aims to determine evapotranspiration and crop coefficient of dwarf-green coconut (Cocos nucifera L.) based on lysimeter measurements and Bowen ratio-energy balance method. The reference evapotranspiration was obtained by the Penman-Monteith approach on daily-scale during the experimental period. The data acquisition system was used to obtain all data from the sensors necessary to determine the energy balance components. The water requirements of coconut palm during the phenological growth stage is 1263.30 mm, with daily average of 3.90 mm d-1. The crop coefficient during this phenological growth stage varies between 0.50 and 1.80, with daily mean of 0.96.