The objective of this work was to evaluate the effects of different storage conditions on the physiological and sanitary quality and oil content of castor bean (Ricinus communis) seeds. Seeds of castor bean plants of the Guarani, and IAC-80 cultivars were stored in two environments (cold room, and room conditions), using three package types (multifoliate Kraft paper bag, and polyethylene bag, and polyethylene bag with vacuum at 1 atm). In addition, another storage condition was evaluated: cryopreservation (-196 °C) in foil paper bags. Seed quality was evaluated before storage and at 4, 8, and 12 months after storage by testing their 7-day and 14-day germination, emergence, health, water content, and oil content. The experiment was conducted in a completely randomized design, with 7×4 factorial arrangement consisting of seven storage conditions and four evaluation times. Cryopreservation is the ideal condition for maintaining the seed physiological quality of the Ricinus communis cultivars used throughout storage. The oil content of the R. communis seeds decreases, and the incidence of Aspergillus spp. and Fusarium spp. fungi increases throughout storage, regardless of the storage conditions.

Evaluating spatial variability of hydraulic properties and salinity of soils is important for an adequate agricultural management of alluvial soils, and protection of riparian vegetation. Thus, the objective of this work was to evaluate the accuracy of geophysical techniques for indirect measurements of apparent electrical conductivity (ECa), using an electromagnetic induction equipment (EM38®), and soil physical hydraulic parameters and their spatial interrelations. The study was carried out at the Advanced Research Unit of the UFRPE, in the Brígida River Basin, in Panamirim, state of Pernambuco, Brazil, in the second half of 2016. This river had a 100 m wide riparian forest strip transversely to the river bank on both sides of the river. A regular 20×10 m grid with 80 points was used to evaluate the soil hydraulic conductivity and ECa. The geostatistics showed the spatial dependence and the dependence of the soil attributes, their spatialization, and precise mapping through indirect readings. Most of the variability (86%) in soil electrical conductivity was explained by indirect readings using the EM38®. Ranges of 80 m, 380 m, and 134 m were found for soil moisture, ECa, and hydraulic conductivity, respectively, presenting strong spatial dependence. The results showed the importance of riparian forests to the maintenance of soil moisture and porosity to the improvement of soil water infiltration capacity even under severe water deficit conditions and soil subsurface layers.

Swine wastewater can be used as a biofertilizer and promote significant improvements in soil physical-chemical attributes and yield. The objective of this study was to evaluate the effects of swine wastewater application on soil and maize yield. The experiment was conducted at the Agricultural Sciences Center of the Federal University of Piauí, in Teresina, Piauí, Brazil, from August to November 2015. The experimental design used completely randomized blocks in split-plot scheme, with five doses of swine wastewater (0, 25, 50, 75 and 100 m3 ha-1) in the plots and two soil depths (0.20 and 0.40 m) in the subplots, with four replications. Exchangeable contents of calcium, magnesium, phosphorus, potassium and sodium, electrical conductivity, pH, sum of bases, base saturation, potential acidity and cation exchange capacity, and crop yield were evaluated. Results showed calcium, magnesium, sum of bases and cation exchange capacity increased with elevated levels of swine wastewater. Potassium and sodium contents however decreased with doses of 51.58 and 52.28 m3 ha-1, respectively. Except for potassium and potential acidity, variables showed higher values at the 0-0.20 m depth.

Vegetable production is an impactful activity, characterized by intensive land use, high input demand, and it requires strategic management adoption, especially in sustainable production systems, where the pillars of sustainability (environmental, social and economic) must be respected. In this sense, the objective of this work was to evaluate economic indicators of lettuce production using Caatinga spontaneous species (Calotropis procera: rooster tree) as fertilizer and cultivated in two seasons (spring and fall-winter) in the municipality of Serra Talhada, PE. The experimental design was in randomized blocks, arranged in a 4 x 4 factorial scheme, with three replications. The first factor was the biomass amounts of green manure (5.4, 8.8, 12.2 and 15.6 t ha-1 on a dry basis); and the second was their incorporation times in the soil (0, 10, 20 and 30 days before lettuce transplanting). The green mass yield, production costs, rate of return, and net profit margin were determined. The amount 15.6 t ha-1 of C. procera allowed higher profitability to the organic production of lettuce, and it is considered ideal to incorporate the green manure 11 (spring) and 15 (fall-winter) days before transplanting the vegetable. The spring crop promoted a superior economic return to the fall-winter planting, demonstrating economic viability even in the smallest amount of C. procera.

Intercropping is a management strategy for the sustainability of agricultural systems, and is suitable for the production of vegetables. Kale is predominantly grown singly, but field observations have indicated that this crop has satisfactory productive potential when grown in intercrops with other vegetables. The objective of this work was to evaluate the agronomic performance and biological efficiency of kale plants intercropped with spice species. The experiment was carried out at the Didactic Horta of the Federal University of Ceará, Fortaleza, state of Ceará, Brazil. The experiment was conducted in a randomized block design with five replications. The treatments consisted of kale grown singly and intercropped with spice species (chives, coriander, basil, and parsley) and these spice species grown singly. The fresh and dry weights of the kale leaves, and the shoot of the spice species were evaluated. The biological efficiency was evaluated by the land use efficiency index (LUE), relative contribution of the kale crop to the LUE, area time equivalent ratio, and system productivity index. The intercropping of kale with parsley resulted in the highest fresh, and dry weights of kale leaves, showing the highest agronomic efficiency.

The number of studies on plant compounds with insecticidal activity has increased in recent years, and one of the primary targets of these compounds is leaf-cutter ants, which are considered the most important pests in Brazilian plantations, especially ants of the genus Atta. The objective of this study was to evaluate the toxic activity of the crude extract and fractions of the leaves of Esenbeckia pumila Pohl (Rutaceae) on Artemia salina and Atta sexdens rubropilosa and to perform a phytochemical study of this plant species. The toxicity of the extract and fractions was evaluated by determining the mean lethal concentration (LC50) on A. salina. The insecticidal activity was evaluated by feeding the ants an artificial diet containing the crude extract or fractions, and the results were analyzed using the log-rank test. The substances were isolated by chromatography, and the molecular structure was determined by spectroscopy. In the bioassay with A. salina, the ethanol extract and dichloromethane and ethyl acetate fractions were highly toxic. The analysis of survival curves indicated that the mortality rate of A. sexdens rubropilosa workers fed different fractions was higher than that of ants fed the control diet, especially the ethyl acetate fraction, with a mean survival time of 3 days and cumulative mortality of 100% on day 21 (p<0.05). The phytochemical study of this plant species allowed isolating the flavonoid rutin and a mixture of the triterpenes α-amyrin, β-amyrin, and lupeol. These results suggest the insecticidal potential of E. pumila on Atta sexdens rubropilosa.

The genetic variability within the crop species Ipomoea batatas is broad, hence, in order to support future breeding programs it is of the utmost importance that germplasm banks be created, conserved, and characterized. Therefore, the objective of this work was to rescue and evaluate the genetic divergence in sweet potato accessions collected in traditional communities of Vale do Ribeira Paulista. Sweet potato samples were collected from quilombos, indigenous villages, caiçaras communities, and small farms. The study was conducted between February 2013 and August 2014 in a randomized block design with three replications. Genetic material included 95 collected accessions and two commercial cultivars. Morphological characteristics of the accessions were evaluated and distances in the genetic distance matrix were estimated by means of multi-category variables, the data being subsequently clustered by the Tocher method. Analysis of the relative contribution of each characteristic and phenotypic correlation of descriptors was also performed. Results evidenced wide genetic diversity among the sweet potato accessions collected in Vale do Ribeira, which were not grouped according to the collection point. The descriptors that contributed more than 60% of genetic diversity included: leaf size, general leaf profile, immature leaf color, petiole pigmentation, predominant branch color, branch secondary color, stem length, cortical thickness, predominant periderm color, and periderm color intensity. Correlations between morphological descriptors was observed in 22.26% of the paired traits.

New hybrid onions that are more productive are currently being cultivated. Information on growth and nutrient accumulation must thus be updated to assist in the refinement of existing recommendations, enabling the better exploitation of the productive potential of these new genotypes. We determined the growth of plants and the accumulation and export of nutrients of the short-day onion ‘Soberana’ established by direct seeding. The experimental design was a randomized block with four replicates and the treatments were evaluation times. Leaf number, tissue dry weight, nutrient accumulation, and the maximum daily rate of accumulation were evaluated throughout the growing cycle. The order of nutrient accumulation was (g plant-1) K (0.72) > Ca (0.38) > N (0.32) > S (0.14) > P (0.08) > Mg (0.06) and (mg plant-1) Fe (2.26) > Mn (1.43) > Cu (0.93) > Zn (0.91) > B (0.85). Macronutrient demand was highest between 61 and 148 days after sowing (DAS), and micronutrient demand was highest between 70 and 148 DAS.

In Brazil, studies on chickpeas (Cicer arietinum L.) have demonstrated the high productive potential of this crop, especially in the Cerrado areas of Cristalina, GO, and Brasília, DF. Due to dry winter climatic conditions, the North of Minas Gerais may be very suitable for the production of this crop. However, more information on chickpea sowing dates is needed. Therefore, the objective of the present study was to evaluate different chickpea sowing times in two municipalities of Minas Gerais State in Brazil: Montes Claros and Januária. The experiment was carried out in a randomized block design, comprising three sowing dates (12 May, 23 June, and 22 July, 2015), and seven replications. The cultivar used was BRS Aleppo, and the chickpeas were harvested 121 days after sowing. The variables evaluated included plant height, productivity, number of pods with one grain, and number of pods with two grains. The data were submitted to analysis of variance, and joint analysis of the experiments was performed. The highest yields were obtained when chickpeas were sown in May in Montes Claros, with a yield of 5.3 t ha-1. In Januária, chickpeas sown in May and June produced yields greater than 3.0 t ha-1. The plants sown in July, considered late for planting, were harvested during the rainy season, which compromised the quality and yield of the grains. In addition, maximum temperatures above 30ºC were recorded from September onwards in both locations, which also resulted in a reduction in the number of grains per plant. Thus, this sowing season is not recommended in the studied region.

No-tillage cotton systems require soil coverage with cover crop residue for a longer time due to the late cycle of cotton. However, decomposition rates may vary between cover crops, and the adjustment of models to describe it is critical to no-tillage cotton management. Two non-linear regression models, exponential (EM) and Michaelis-Menten (MM), were adjusted to dry matter decomposition of cover crops in a cotton no-tillage system, in Brazil. Three field trials were performed in 2012 for the cover crops Urochloa ruziziensis (brachiaria), Pennisetum glaucum (pearl millet), and Cajanus cajan (pigeon pea). Samples of cover crop were collected at 20, 50, 70, 110, 140, and 170 days after sowing upland cotton to measure dry matter decomposition. MM showed better adjustment than EM for all cover crops. The estimations of half-life parameters were different between the cover crops, suggesting that each cover crop has its own rate of decomposition. For pearl millet, brachiaria, and pigeon pea, the half-life estimation by exponential model was over the MM in 9, 12, and 12 days.