The growing competition for good-quality water is forcing the use of saline water for irrigation in several areas around the world. The objective of this study was to evaluate the influence of different electrical conductivities of irrigation water on the maize production aspects. The study was conducted in the field from August to December 2017 at the Experimental Farm of the Universidade da Integração Internacional da Lusofonia Afro-Brasileira (UNILAB), Redenção, CE, Brazil. A randomized complete block design with five irrigation water salinity (1.0, 2.0, 3.0, 4.0 and 5.0 dS m-1) and four repetitions was used. The evaluated variables were: unhusked and husked ear weights, husked ear length and diameter, cob weight, 1000-grain weight and yield. The increase of salt concentration in irrigation water reduced the unhusked and husked ear weights, cob weight, 1000-grain weight and yield. Ear length and diameter were not influenced by the increase in water salinity.

ESTRESSE SALINO E COBERTURA VEGETAL MORTA NA CULTURA DO MILHO - DOI: 10.7127/rbai.v12n700889

Salinity is a complex phenomenon that affects the metabolic processes of the plant, changing the physiological and biochemical parameters. In this context, the objective of this study was to evaluate the effect of irrigation water salinity on growth, biomass and gas exchanges in soybean crop in soil with and without biofertilizer. The experiment was carried out in a greenhouse at the experimental area of ​​the Agrometeorological Station of the UFC, Fortaleza, CE, Brazil, from May to June 2016. The treatments were distributed in randomized blocks in a 5 × 2 factorial scheme, corresponding to the levels of irrigation water salinity: 0.8; 1.6; 2.4; 3.2 and 4.0 dS m^-1, in soil without and with bovine biofertilizer, in five replicates. The following variables were evaluated: growth (plant height, number of leaves, stem diameter, and leaf area), biomass (leaf, root and total dry matter) and gas exchanges (photosynthesis, stomatal conductance and transpiration). Irrigation water salinity reduced photosynthesis, stomatal conductance and transpiration, but with less intensity in the plants that received bovine biofertilizer. The aerobically fermented bovine biofertilizer attenuates saline stress on the initial growth and biomass of soybean plants.

IRRIGAÇÃO COM ÁGUA SALOBRA NA CULTURA DO RABANETE EM SOLO COM FERTILIZANTES ORGÂNICOS - DOI: 10.7127/rbai.v10n600514

Forest floor litter can influence biogeochemical cycling and root growth in Pinus taeda systems, especially on low soil fertility sites. The impact of fertilization and liming on forest floor litter (quantity, elemental composition and root presence) was evaluated in a Pinus taeda stand in southern Brazil. A nutrient omission experiment was initiated in November 2008 on an 11 year-old Pinus taeda plantation. The experiment was a randomized block design with seven treatments and four blocks. The treatments were: complete (macro + micro + lime); minus macronutrients; minus micronutrients; minus K; minus Zn; minus lime; and control. In 2012, forest floor litter samples were collected, divided by layer (new litter, old litter, coarse fragmented forest layer > 2mm, fine fragment forest floor < 2mm, and fine roots) and analyzed for concentrations of Na, Al, and total nutrients. Results indicated that lime increased Ca and Mg concentrations, reduced Al toxicity, and improved fine root growth. An increase in fine roots was observed in treatments without K. There were large increases in Fe and Al as a function of litter age and increased Mn in fragmented litter when lime was applied. There was little variation in forest floor litter accumulation in all treatments. Elemental abundance was C>N>Fe>P>Ca>K>Mg>Mn under control conditions and C>N>Ca>Mg>P>Fe>Mn>K for the complete treatment. Occurrence of needle chlorosis, similar to that reported for Mg, and low growth under lime omission indicate that Mg was a major factor limiting growth. Fertilization and liming affected the bio-cycling of nutrients, Al toxicity, and root growth.