Saline-sodic soils are a major impediment for agricultural production in semi-arid regions. Salinity and sodicity drastically reduce agricultural crop yields, damage farm equipment, jeopardize food security, and render soils unusable for agriculture. However, many farmers in developing semi-arid regions cannot afford expensive amendments to reclaim saline-sodic soils. Furthermore, existing research does not cover soil types (e.g., Luvisols and Lixisols) that are found in many semi-arid regions of South America. Therefore, we used percolation columns to evaluate the effect of inexpensive chemical and organic amendments (gypsum and cow manure) on the reclamation of saline-sodic soils in the northeast of Brazil. Soil samples from two layers (0–20 cm and 20–40 cm in depth) were collected and placed in percolation columns. Then, we applied gypsum into the columns, with and without cow manure. The experiment followed a complete randomized design with three replications. The chemical amendment treatments included a control and four combinations of gypsum and cow manure. Percolation columns were subjected to a constant flood layer of 55 mm. We evaluated the effectiveness of sodic soil reclamation treatments via changes in soil hydraulic conductivity, chemical composition (cations and anions), electrical conductivity of the saturated soil-paste extract, pH, and the exchangeable sodium percentage. These results suggest that the combined use of gypsum and cow manure is better to reduce soil sodicity, improve soil chemical properties, and increase water infiltration than gypsum alone. Cow manure at 40 ton ha−1 was better than at 80 ton ha−1 to reduce the sodium adsorption ratio.

The use of wastewater has emerged as alternative to control environmental pollution and a viable option to improved water availability in the arid and semiarid zones. In this study, the effects of irrigation solution with domestic sewage effluent and, of growing substrate on growth of Aroeira seedlings was examined in a greenhouse experiment. The effects of five irrigation solution (Public-supply water, PSW, domestic sewage effluent, DSE and the mixtures of 75% DSE + 25% PSW, 50% DSE + 50% PSW and 25% DSE + 75% PSW) and two growing substrate (75% soil + 25% bovine manure and, 75% soil + 25% coconut fiber) were used in a completely randomized block design, arranged as split plots with three replications for each treatment. The evaluations were made at 30, 60, 90 and 150 days after planting, and the parameters following were measured: stem diameter, shoot height, relationship between height and diameter, shoot/root dry matter ratio, dry matter of the root, shoot and total and, Dickson index. The analysis results indicated that the irrigation solution composed by raw sewage effluent or mixed with Public-supply water increased the growth and improved morphological index of Aroeira seedlings, being the better development found when plant of Aroeira were grown in bovine manure + soil substrate under irrigation with solution containing 100% domestic sewage effluent.

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Presente trabalho teve como objetivo analisar a população de coliformes totais, termotolerantes e a Salmonella presentes no solo irrigado com efluente doméstico tratado. As amostras do solo foram coletadas com trado holandês, nos meses de abril e setembro de 2012 no período chuvoso e seco respectivamente, na área do cultivo do capim-elefante (P. purpureum) irrigada com água residuária de origem domestica. as amostras foi feita em 12 pontos aleatórios, nas linhas do plantio com profundidades de 0 - 0,40 m, em o cada duas coletas simples para formar uma composta. Em seguida foram levadas ao Laboratório de Inspeção de Produtos de Origem Animal (LIPOA) da UFERSA, para analise da salmonella e as amostras para analise de coliformes foram encaminhadas para o Laboratorio de Quimica da UERN, para indicador de contaminação microbiológica. Foi determinada a quantidade de coliformes totais e termotolerantea (Escherichia coli) e salmonella por grama de solo. As amostras de coliformes foram analisadas pela técnica do Número Mais Provável por 100 g-1 (NMP 100 g-1) de coliformes totais e termotolerantes (CTe) foi realizados pela técnica dos tubos múltiplos NMP. Para o isolamento de Salmonella spp, utilizou-se a técnica de concentração por membrana filtrante, de 42 mm de porosidade por 142 mm de diâmetro.

HIGHLIGHTS Growth and leaf area of mini watermelon in hydroponic cultivation are reduced at electrical conductivity above 4.00 dS m-1. Electrical conductivity of up to 6.90 dS m-1 does not reduce the net photosynthesis of mini watermelon in hydroponic cultivation. Coconut fiber is the best hydroponic substrate for mini watermelon.

Cowpea is an important source of protein, being the main subsistence crop in the northeast region of Brazil, where water restriction and salinity are limiting factors. Identification of saline stress tolerant varieties can aid crop expansion and improve crop yields. The objective was to study the tolerance of traditional varieties of cowpea to the salinity of irrigation water in the emergency and initial growth phase. The experiment was carried out in a greenhouse using a completely randomized design (DIC), in a 23 x 2 factorial scheme, composed of 23 cowpea varieties (Canapu Vermelho, Boquinha, Pingo de Ouro, Sempre Verde, Ceará, Baeta, Manteiga, Roxão, Costela de Vaca, Feijão Branco, Coruja, Rabo de Peba Branco, Sopinha, Canapu Branco, Lisão, Canapu Miúdo, Sempre Verde Ligeiro, Vagem Roxa, Ovo de Peru, Rabo de Peba Miúdo, Feijão Azul, Canário, and Paulistinha) and two levels of salinity of irrigation water (S1 = 0.5 and S2 = 5.5 dS m-1), with four repetitions of 50 seeds. The seedlings were evaluated for emergence, vigor, salinity tolerance index, and dissimilarity. Increased salinity of irrigation water reduced emergence, vigor and dry matter accumulation of cowpea varieties. The cowpea varieties ‘Lisão’, ‘Costela de Vaca’, ‘Canário’, ‘Feijão Branco’, ‘Ceará’, and ‘Boquinha’ are the most tolerant to salinity, while the varieties ‘Sempre Verde’ and ‘Manteiga’ are the most sensitive to salinity in the emergency and initial growth phase.

The objective of this study was to evaluate the effect of light availability and salt stress on the growth and quality of hazel sterculia seedlings. The experiment was conducted with two light conditions-full sun (L1), and 50% shading (L2)-and five salinity levels in the irrigation water-1.0 (S1), 2.2 (S2), 3.2 (S3), 4.2 (S4), and 5.1 (S5) dS m-1. The environment with 50% shading was the most suitable to produce hazel sterculia seedlings, even under high salinity (5.1 dS m-1). Increasing salinity negatively affects the growth and quality of hazel sterculia seedlings. Therefore, controlling sunlight availability and irrigation water saline conditions increases rooting potential and seedling survival in the field.

HIGHLIGHTS Irrigation with saline effluent from fish farming does not reduce cherry tomato fruit production. The use of saline effluent from fish farming in irrigation reduces production and vigor of cherry tomato seeds. Application of effluent in the appropriate stages promotes production of fruits and seeds of cherry tomato equal to those of the control.