The aim of this paper was to evaluate the influence of different methods of dormancy breaking and substrates in the emergence and early growth of seedlings canafístula (Peltophorum dubium (Sprengel) Taubert). The experiment was conducted in a randomized block design in a factorial 5 x 4, with five substrates, Bioplant®; 75% Bioplant® + 25% bagasse from sugar cane (75B+25BC); 50% Bioplant® + 50% bagasse from sugar cane (50B+50BC); 25% Bioplant® + 75% bagasse from sugar cane (25B+75BC); bagasse from sugar cane (100%) and four methods of breaking dormancy (control, mechanical scarification using sandpaper, immersion in hot water and scarification with concentrated sulfuric acid) with three replications of 12 seeds. We evaluated the index of emergency speed; average time of emergency; emergence percentage at 7, 14 and 28 days after sowing, the dry mass of shoot and root dry mass. Immersion in hot water and chemical scarification with sulfuric acid (98%) are efficient methods to overcome seedcoat dormancy in seeds of canafístula. The substrates Bioplant® and 75B +25BC provide higher initial growth of seedlings.

The aim of this paper was to evaluate the contribution of different strains of rhizobia in the distribution of dry material and grain yield in cowpea plants, grown in cerrado in the state of Tocantins. The experiment was conducted in 2007/2008 season in cerrado in Gurupi, TO. Five treatments were studied with strains BR3301, BR3302, BR3267, BR3299 and BR3262 and treatment as a control (no inoculation and fertilizer). Plants were collected at 15, 25, 35, 45, 55 and 65 days after emergence (DAE) to determine the distribution of dry mass of leaves, stems, flowers and pods and the weight ratio of plant parts. Grain yield was determined at harvest as grain moisture reached 13%. We established the Pearson correlation coefficient of variables. The witness and BR3299 treatments promoted greater dry mass of plants at 65 DAE. The highest yield was obtained by the witness and BR3267. Further study is needed on the selection of strains of nitrogen-fixing bacteria in cowpea under various soil and climate in the state of Tocantins.

The nitrogen (N) and phosphorus (P) generally are the two nutrients that occur in lower levels in the soil in relation to the need of the plant and are the nutrients most required by the maize crop. With the present work aimed to define the levels of N and P2O5 associated to the maximal economical of green corn in an alkaline soil of the city of Baraúna-RN. The maize hybrid AG 1051 was planted in spacing of 0.70 x 0.23 m and harvested on the condition of green corn to 75 days after planting. Were applied 17 treatments, being 16 treatments resulting from the combination between four doses of N (30, 60, 90 and 120 kg ha-1) and four doses of P2O5 (30, 60, 90 and 120 kg ha-1) and a control treatment, in which not applied any dose of these nutrients. The experimental design was in randomized blocks with four repetitions. The characteristics evaluated were: number and total weight of cobs, number and weight of marketable covered cobs and number and weight of marketable uncovered cobs. The increase of the availability of N and P in soil, as a result of fertilizing, positively influences positively the weight of green maize ears. The culture of green corn responded better to phosphorus fertilization than nitrogen fertilization, showing that in the soil of the experimental area the P was more limiting to the production than the N. Although the majority of production of marketable covered cobs has been estimated for the application of 120 kg ha-1 N + 106 kg ha-1 P2O5, the doses of maximum economic and environmental efficiency recommended were 60 kg ha-1 N + 106 kg ha-1 P2O5.

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.