The paper aimed to examine the equity investment in shrimp production, a typical farm of the western region of Rio Grande do Norte, using the following criteria for project selection: Net present value (NPV), Internal Rate of Return (IRR), payback and Cost/benefit analysis (C/B). In a complementary manner it has evaluated the likelihood of change in Net Present Value and Internal Rate of Return, through the risk analysis. In the risk analysis input variables (inputs) were considered: the price paid to producers per Kg of shrimp and price of Kg of ration HD-35%, which represents 36.42% of the total cost per production cycle. The selected variables or (outputs) were the Net Present Value at 12% and 6%, and the Internal Rate of Return. The results of investment analysis, without considering price risk were: R$ 214,943.93 NPV 12% NPV 300,819.13 6%, 60% IRR, payback of two years and 1,4 Interface B/C. The survey results indicate that shrimp farming represents for the rural sector of Rio Grande do Norte, a leading alternative investment, considering that the average IRR, considering the risks of price, was 35.21%, ie any other investment would only be desirable, in comparison with investment in shrimp production, if present rate of return higher than 35.21%.

Heteropterys tomentosa A. Juss. belonging to the Malpighiaceae family has its roots extracted and used in the Cerrado of Mato Grosso, mainly as a tonic and aphrodisiac. Evaluation of seedling growth may provide information for growing and selecting plants of the species. In this paper the aim was to evaluate the growth of progenies of H. tomentosa in a greenhouse. 30 progenies were evaluated in a randomized experimental design with three replications of 10 plants per plot. The variables analyzed were height (cm/plant), diameter (mm/plant) and number of leaves/plant. The plants were grown at an average speed of 0.38 cm per day. However, the average speed was higher at 120 days, with about 0.53 cm.day. The diameter increment was much lower in the first 60 days, about 0.01 mm.day, but there was an increase to 0.03 at 100 days, 0.02 mm.day stabilizing again to the end of 150 days. The increase in speed to the number of leaves at 45 days and 105 days was the same (0.13 leaves.ind.day). However, it was between 60 and 90 days after planting that the growth rate was higher (0.26 leaves.ind.day). The highlights were significant associations between fresh weight and dry weight and between length and weight of the plant. It is concluded that the seedlings of H. tomentosa kept in a greenhouse grow up too quickly and can be transplanted to grow efficiently. The selection of individuals for increased root production can be done by those with the greatest number of leaves.

Agave sisalana Perrine ex Engelm is an important specie to economy of the semiarid region of Brazil because of it is an efficient source for production of fibers. Information about the anatomy can contribute greatly to plant production, however, there are few papers on the structural anatomy of this specie. The current paper aimed at describing the anatomy of the leaves, roots and rhizomes of Agave sisalana. Adult plants were collected in experimental plots at the Universidade Federal do Recôncavo da Bahia, in Bahia State, Brazil. The samples were processed using standardized plant anatomy techniques. Histochemical tests using Sudan Red and Sudan Black were performed to identify lipophilic substances. A number of characteristics typical of plants adapted to dry environments were observed, including a thick cuticle on both leaf faces. The leaves were phystomatic and had tetracitic stomata, long sub-stomatal chambers, isobilateral mesophyll, unistratified epi-dermis, papilla, cuticular flanges, and alternate collateral vascular bundles accompanied by fibrous sheaths. The roots had a velamen, a cortex with large rounded cells, and three layers of sclerids adjacent to the uniseriate endodermis. The rhizome was of the atactostele type and had no endodermis. OuvirLer foneticamente.

The Northeast, including Maranhão, there are great poles of development for the maize crop, due to a good potential for growth of agribusiness and marketing of agricultural production. In order to analyze the productivity of maize in this region and compare the average performance between different genetic classes, we analyzed different types of hybrids and open pollinated varieties. They were evaluated in two essays. The first, with 42 cultivars, 23 simple hybrids, 11 hybrids and 8 triple double hybrids. The second, with 40 cultivars, 12 simple hybrids, hybrid 7 doubles, 7 triples and 14 hybrid varieties of open pollinated. The design was a randomized complete block with two replications. Each plot consisted of two useful rows spaced 5.0 m at 0.90 m. The tests were grouped and the average productivity of the different gene classes was compared by t test and confidence intervals. On average, single-cross hybrids were superior to other types of cultivars. There was no difference between double and triple hybrids, but the two types of cultivars were higher than the group of open-pollinated variety. This result demonstrates the importance of the commercial exploitation of heterosis in maize. However, it is not possible to generalize on the recommendation of cultivars, because despite the obvious differences regarding the average yield on a small scale some simple and triple hybrids produced less than a few doubles and even hybrid varieties.

The aim of this paper was to evaluate biochemical activities related to promotion of plant growth of isolates of the genus Bacillus originated from areas under maize cultivation, and to evaluate the genetic similarity among the isolates using PCR-based RAPD markers. Several strains of the genera Bacillus were isolated from twenty distinct maize production areas of the State of São Paulo, Brazil. Forty isolates were obtained and characterized as antagonistic to plant pathogenic fungi, production of auxin (IAA), phosphate solubilization in vitro and root colonization. The potential for phosphate solubilization was not identified in any of the isolates. In addition, the majority of the isolates did not show any antagonistic effect against Fusarium oxysporum and Colletotrichum truncatum. Based on root colonization, six Bacillus isolates were selected to evaluate their growth-promotion activities in maize. All the six isolates increased root growth, while only one isolate did not promoted shoot growth and nutrient uptake in plants when compared to control. Low genetic similarity among the selected isolates was detected by RAPD analysis using eleven primers. Our results showed the utility of the in vitro selection criteria used in this study for screening of Bacillus sp. with plant growth-promoting activity, as they may reduce the number of Bacillus isolates required at the final screening stage in field.

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.

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.

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 timbó (Magonia pubescens St. Hil.), tree typical of the cerrado, has medicinal, timber, craft, ornamental and larvicidal. The aim of this paper to evaluate seedling emergence of M. pubescens under different light conditions. The experiment was conducted in chambers B.O.D. temperature 30 °C, substrate sand, in a completely randomized design with five treatments and four replications of 50 seeds. The treatments were: 1) a photoperiod of 24 hours, 2) absence of light, 3) a photoperiod of 12 hours, 4) a photoperiod of 8 hours and 5) a photoperiod of 16 hours. The smallest percentage and emergence rate (45% and 14 days) were provided 12 h light and 12 h dark, and the emergence in all treatments was high (90 to 97.5%) and emergency speed too (7.4 to 10.5 days). The seeds of M. pubescens photoblastic are neutral in laboratory conditions at a temperature of 30 ºC and the emergence occurs between four and nine days.