Having to evaluate the effect of varieties and phosphorus fertilization on growth and productivity of castor beans, is an experiment conducted at the Center for Agricultural Sciences, located in Rio Largo- AL. The paper was a 5 x 2 factorial, consisting of five doses of P2O5 (0, 45, 90, 135 e 180 kg ha-1) using triple superphosphate as source, and two varieties of castor bean, (BRS 149 Nordestina and BRS 188 Paraguaçu), with the treatments distributed in a randomized block design with four replications. We determined leaf area (LA) and plant height (PH) 30, 60, 90 and 120 days after transplanting (DAT), the length of the primary racemes (LPR) and subsequent (LSR), the number of racemes throughout the cycle (NR), the seed yield (SY) and dry matter accumulation in shoot (DM). The P fertilization increased the leaf area only at 30 and 120 DAT, while for plant height, the effect was only observed at 30 DAT. There was a quadratic effect of phosphorus for the LPR, NR, SY and DM. The variety BRS 188 Paraguaçu produced more racemes, but on the other side of the racemes BRS 149 Nordestina were longer.

Due to continued machinery, soil mobilization has caused considerable changes in both soil bulk density (physical attributes) and organic C content, risking crop yield reduction and negative environmental effects. In this context, this work aimed at assessing changes in both physical attributes and in organic C content of a Argissolo Vermelho-Amarelo surface horizon, subjected to no-tillage (NT) and conventional tillage with disk plow (DP), heavy harrow (HG), and disc plow plus harrow (DP+HG) for 23 years. A natural forest fragment (NF) was used as reference area. A randomized-block design with 8 x 12 m plots and four replications was used. Soil samples were collected at 0-5, 5-10, 10-20, and 20-40 cm depths in order to assess soil density, total organic carbon content, porosity, saturated hydraulic conductivity, and aggregate stability. Results showed that continued cultivation increases soil physical degradation, as evidenced by both macro porosity and total porosity reduction, aggregate stability, saturated hydraulic conductivity, total organic carbon, and soil density increase. The NT was found to best contribute to soil physical properties improvement and total organic carbon recovery in 0-5 cm surface layer.

The cowpea (Vigna unguiculata (L.) Walp.) is one of the most cultivated leguminous in the world. In spite of being a very studied species, there are theoretical models for the development for different habits of culture. The concept of thermal time, replacing the chronological time, has been used frequently, with the advantage to be independent of location and time of sowing. Considering the relevance of the activity for the State of Piauí, this work had the purpose of describing fenology of the variety BR 17 - Gurguéia, relating the number of day-degrees necessary to the development of each fenological state. An experiment was realized in the Departamento de Fitotecnia of Centro de Ciências Agrárias of Universidade Federal do Píauí, Teresina- Piauí. It was found that the number of vegetative stages is indefinite and that the variety shows at least six reproductive stages. The vegetative stage V1 (2º in the main branch with leaflets fully open) was the longest and from the stadium V10 (11º in the main branch with leaflets fully open) was overlap of vegetative and reproductive stages. The cultivar BR 17 - Gurguéia in rainfed crop, requires 818.2 degree-days from sowing until the early reproductive stage and 1103.5 degree days from planting to the end of the reproductive cycle, with wide adaptability for the State of Piauí; the cultivar BR 17 - Gurguéia presents six reproductive stages, LV the stadium is the longest among the vegetative and reproductive stages, individually, need a greater number of degree- days that the vegetation

This paper aimed to evaluate the effects of herbicides on the biomass and nodulation ofcowpea. The experiment was conducted in greenhouse, in experimental design with randomized blocks, in factorial arrangement 4x2 + 2, corresponding applications of the herbicide bentazon, clethodim, fomesafen and smetolachlor, the recommended dose (RD) and recommended twice (RDA) in four periods of development of cowpea (20, 30, 45 and 55 days after planting, DAP). An inoculated control treatment without herbicide application and a control without inoculation, no application of herbicide and nitrogen fertilizer were included. Inoculation was performed with the strains INPA UFLA 03-11B and 03-84. The results showed for the experiment in a greenhouse that bentazon and clethodim, both at the recommended dose and double dose, provide low phytotoxicity to cowpea and has little influence on nodulation and crop biomass. The herbicide smetalochlor presents high degree of phytotoxicity in cowpea, completely inhibits the vegetative growth when applied at twice the recommended dose.

Agricultural activity changes the soil physical properties, making them unfavorable for plant development. The objective of this study was to evaluate the soil physical properties and total carbon stocks in the layers of 0 to 0.10 and 0.10 to 0.20 m depth, in areas under different management, and compare with the native forest soil. The study was conducted between May and December 2009, at University of Oeste Paulista, Presidente Prudente (SP). The experiment was conducted in a randomized block design with four replicates in a 4x2 factorial, with four soil management systems (no tillage (NT), conventional tillage (CT), pasture and native forest) and two sampling depths (0 to 0.10 and 0.10 to 0.20 m). We evaluated the parameters of soil bulk density, porosity, organic matter content and total carbon stocks in soil. Human intervention through agricultural practices reduces the stock of carbon in soil to levels well below the conditions found in native forest, besides providing the soil physical conditions worse than that of the soil kept under forest.

The spreading of umbuzeiro (Spondias tuberosa Arruda Câmara) occurs sexual and asexual forms, with little information about the propagation by cuttings. The aim of this paper was to evaluate the effects of concentrations of indole butyric acid (IBA), length and timing of collection of propagules in propagating of umbuzeiro. The experimental design was randomized blocks in factorial scheme 5 (IBA concentrations: 0, 1500, 3000, 4500, 6000 mg.L-1) x 2 (length of cuttings: 10 and 20 cm) x 2 (times of collection of cuttings: march and september) with three replications of twenty cuttings per experimental unit. The cuttings were immersed in IBA solution for the time of 10 seconds and placed in polyethylene bags containing substrate composed of sand, clay and vermicompost (3:1:1 v / v), which were packed and kept for 90 days under nursery, mesh that allowed the passage of 25% brightness. After this period the following variables were analyzed: percentage of rooted cuttings and shoots, number average root cuttings, and the mass of the fresh matter roots and shoots. The most rooting percentage was obtained in the stakes of umbuzeiro 20 cm inlength treated with IBA (6000 mg.L-1), planted in march. The smallest roots of umbuzeiro in September was probably because the plant was starting the process of flowering.

In order to determine the effect of organic fertilizer on growth of seedlings of melon inoculated with arbuscular mycorrhizal fungi (AMF), an experiment was conducted under greenhouse conditions. The experimental design adopted was a completely randomized design with four treatments and four replications. Treatments consisted of melon plants cultivated on sterile and non sterile soil in the presence or absence of organic compost. The melon seeds were germinated in trays containing substrate formed by 70% of Soil + 30% of green coconut powder, and the mycorrhizal inoculation used a mixture of the species Glomus clarum and Glomus intraradices, applied at the time of sowing. The seedlings with the first definitive sheet were transplanted into pots with sterile or non sterile soil, fertilized or not with organic compost. After 30 days from transplanting plants were harvested for determining the weight of fresh and dry shoot, stem diameter, arbuscular mycorrhizal colonization and content of macro and micronutrients. Organic compost addition did not influence arbuscular mycorrhizal activity and also increased shoot dry weight. AMF colonization of roots showed influence on macro (N, P and Ca) and micronutrients (Fe and Mn) shoot content on soil sterile with organic compost.

The population growth not only demands further exploration and use of water, but generates different types of wastewater, such as sewage which is dumped directly into watercourses. In this context, the aim of this study was to evaluate the influence of the use of wastewater from domestic sources on the growth of plants of physic nut during the third year of production under protected ambient. A randomized block design in a 5 x 2 factorial scheme was used, the factors being five levels of water replacement - WR (0.25, 0.50, 0.75, 1.00 and 1.25 times water consumed by the plant) and two levels of phosphorus (135 and 200 g plant-1 year-1) with four replications. Plants were grown in recipients with a capacity of 200 L and in the beginning of the 3rd year of production (present study) a drastic pruning was performed. The variables plant height, stem diameter; leaf number and leaf area of the physic nut were influenced by the depth of water replacement from 30 days after pruning (DAP). The leaf number and stem diameter were affected by phosphorus dose at 30 and 90 DAP, respectively. The plant height and leaf area were influenced by the interaction (WR x phosphorus dose) at 30, 60 and 90 DAP. The weight of the fruit and water use efficiency of physic nut were affected by the depth of water applied but were not influenced by phosphorus dose.

Aiming to evaluate gas exchange and concentration of macro and micronutrients in leaves of physic nut grown under saline conditions, an experiment was conducted in protected ambient adopting a randomized block design in factorial scheme combining five levels of irrigation water salinity ECw (0.6; 1.2; 1.8; 2.4 and 3.0 dS m-1) and two levels of phosphorus (135 and 200 g plant-1) and with four replications. Each plant was grown in pots with a capacity of 200 L. The gas exchange rates (leaf temperature, transpiration, stomatal conductance and photosynthesis) were obtained using a portable photosynthesis meter (IRGA), in the fourth expanded leaf from the apex of the plant. To determine the nutrient content of the plant, the limbo located between the fourth and fifth leaf below the inflorescence was used. The determination of nutrients followed the methodology described by Silva (1999). It was found that the salinity level of irrigation water affected the variables of gas exchange and accumulation of the minerals which has following sequence: K > N > Ca > Cl > Na > Mg > P > S > Fe > Mn > Zn > Cu. With the exception of copper all evaluated nutrients and increased with increasing salinity of irrigation water. The lowest dose of P2O5 used was sufficient to allow the development of the plant during the experimental period, there was no effect of its increase in photosynthetic parameters evaluated.

The riparian forests, belonging to the permanent preservation areas, are of fundamental importance for the preservation of water quality and minimize the effects of erosion on soil and thus the sedimentation of river. The land use of these areas cause environmental risks, especially to water resources. The geospatial technologies are, in the current scenario, as a tool that shows the real situation of the area, identifying the critical points, thus contributing to better management of these areas. Therefore, this study aimed to establish a spatial study of APP of the Mossoró river in urban area of municipal district of Mossoró, in the state of Rio Grande do Norte, identifying the main causes of degradation and it's consequences to environment, especially the water resource, through geoprocessing's techniques. Geographic Information System (GIS) were used to spatially delimitate the area and image processing. Deforested areas comprised 310 ha, being more concentrated among the East-West Bridge and Barrocas's dam. Edification areas were more concentrated in Santa Luzia's Island and between Castelo Branco and Jerônimo Rosado's Bridges, occupying 78 ha. The areas covered by vegetation comprised 70 ha, which more concentrated in the area of Genesio' dam. There was enough sources of water pollution, especially domestic sewage.