Valdécio dos Santos Rodrigues

Loblolly pine (Pinus taeda L.) is one of the most planted forest species in the Americas. Since few studies have comprehensively assessed loblolly pine responses to fertilization, the present study performed a meta-analysis of the Americas based on 44 publications (1970-2022) of loblolly pine fertilization under field conditions. In general, fertilization increased root dry matter (+33%), litter (+21%), plant height (+6%), trunk diameter (+9%), wood yield (+30%), and needle concentrations of P (+9%), K (+36%), Ca (+17%), Mg (+14%), and S (+12%). Wood production was higher with residue fertilization, primarily with use of composite residues (cellulosic sludge + ash), compared to mineral fertilization. In regards to mineral applications, wood production was higher when multiple nutrients were added from fertilization and liming operations. Applications at planting (< 1 year) or on established trees (2-8 years), showed similar increases in wood production with higher responses occurring on sandy soils. These factors generally increased needle nutrient concentrations, except for no alteration or slight decreases in N under most conditions. The present study revealed loblolly pine responses to contrasting application strategies, which can help identify efficient fertility management practices for this commercially significant tree species.

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.

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.

ATRIBUTOS QUÍMICOS DO SOLO EM ÁREA CULTIVADA COM MILHO SOB IRRIGAÇÃO COM ÁGUA SALINA - DOI: 10.7127/rbai.v12n7001016

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

A salinidade da água é um dos maiores problemas que limita o crescimento e a produção agrícola nas regiões de climas árido e semiárido do Nordeste. O objetivo do trabalho foi avaliar o efeito do estresse salino da água de irrigação no crescimento inicial e no acúmulo de biomassa do milho. O experimento foi conduzido em campo no período de agosto a setembro de 2017, na fazenda experimental de Piroás da Universidade da Integração Internacional da Lusofonia Afro-Brasileira. O experimento foi conduzido no delineamento em blocos casualizados e quatro repetições. Os tratamentos foram constituídos de cinco condutividade elétrica da água de irrigação (1,0; 2,0; 3,0; 4,0 e 5,0 dSm-1). Aos 45 dias após a semeadura foram analisadas a altura de plantas, diâmetro do caule, número de folhas, área foliar, comprimento da raiz, massa seca da parte aérea, da raiz e total. Todas as variáveis foram reduzidas linearmente com o aumento da salinidade na água de irrigação. O aumento do teor salino das águas de irrigação foi prejudicial ao crescimento em altura, diâmetro do caule, número de folhas, área foliar e comprimento da radicular, também afetou negativamente o acúmulo da matéria seca da parte aérea, da raiz e total das plantas de milho.

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.