The optimization of nutritional efficiency is critical to increase productivity and reduce produc- tion costs. However, the identification of lines with greater efficiency and responsiveness to phosphorus is of great importance, with the in intention to join the hybrid, these traits at once and, moreover, the best way to select them. Thus, the objective of this study was to evaluate which characters should be considered in the se- lection of genotypes efficient and responsive to phosphorus in sorghum. The correlations were split into direct and indirect basic variables of efficiency and responsiveness to phosphorus through path analysis. The character that most influenced the efficiency of sorghum lines to phosphorus was harvest index to utilization efficien- cy and dry matter to absorption efficiency and use, under conditions of stress. Under conditions of adequate phosphorus fertilization, the trait with the greatest influence for evaluation of responsiveness was dry grain mass to the apparent recovery efficiency, physiological and agronomic.

Agricultural use of soil resources under irrigated conditions requires constant monitoring of the soil quality attributes due to important soil functions related to soil water storage and distribution, aeration and root growth. The present study aimed to evaluate the impact of citrus cultivation, under irrigated conditions, on the physical quality of a Yellow Ultisol through determination of soil pore size distribution, bulk density and soil water retention, in the Neópolis flat land irrigated perimeter, Sergipe. Soil core samples were collected from the 0-0,10 m, 0,10-0,30 m and 0,30-0,50 m layers, with three replications, in a 15 ha citrus orchard. The same soil type under native forest was also evaluated as a reference of soil quality. It was observed reduction in soil total porosity, macroporosity as well as available water as a function of citrus cultivation. Such alterations in soil physical quality influence negatively root development and plant productivity and also call attention to the need of soil quality monitoring as well as best irrigation management practices. Evaluation of soil quality under native forest was efficient in showing the magnitude of soil alterations as a result of changing in soil use.

In order to study the effect of nitrogen sources upon the yields and nutrition of corn for silage and on the chemical attributes of a Cambisol, at Northern of Minas Gerais, Brazil, under calcareous water. The cultivar used was Decalb 390®, with a spacing of 0,8 m x 0,2 m. The base fertilization consisted in 330 kg ha-1 of formulation 4-30-10 and 50 kg ha-1 of FTE-BR12. Two equal dosages of 40 kg ha-1 of K2O, in the KCl form, were applied 45 and 60 days after corn sowing (DAS), phenologic phases V7 and V10 . The experiment it was realized in a randomized blocks design with six repetitions, been the treatments constituted by: ammonium sulfate (topdressing manuring), urea (topdressing manuring), Crotalaria juncea (before de maize crop). The Nfertilizers were applied parceled into three equal dosages of 40 kg ha-1, 30 DAS, with 15 days between fertilizations. The corn yields increased above control treatment average in 33, 27 and 14 t ha-1 with ammonium sulfate and urea topdressing and with C. juncea pre cropped, respectively. The ammonium sulfate use allows better recovery rate of the N applied by the extractor and higher uptake of Fe, Mn, Zn and S by the corn plants.

The bovine biofertilizer applied through irrigation water in the soil (bio fertigation), can be a viable organic source to maintain fertility levels in agricultural production systems. So, this work was aimed at evaluating the effects of different concentrations of bovine biofertilizer applied by fertigation on corn growth, gas exchange and yield. The experiment was conducted under full sun exposure, in Fortaleza, Ceara, in 100 liter (100 L) vessels. The experimental design was that of randomized blocks with five treatments and five repetitions. Treatments consisted of 0.5 L doses (per plant) of a fertigating solution (biofertilizer + water) weekly applied, with a different biofertilizer concentration to each treatment, as follows: C0 = 0% biofertilizer (control), C1 = 12.5%, C2 = 25% biofertilizer, C3=50% biofertilizer, C4 = 100% biofertilizer. We analyzed the effects on the following variables: plant height, stem diameter, leaf number, shoot dry weight, photosynthesis, stomatal conductance, transpiration and yield. The biofertilizer was the most efficient considering the initial growth and gas exchange. Also, the bovine biofertilizer treatments (as a whole) favored the increase in the weight of 1000 seeds and grain yield.

The objective of this study was to evaluate morphophysiologic and productive characteristics from a modern variety of cowpea, cv BRS Novaera, under different plant densities. The experiment was con- ducted out at city of Alvorada do Gurguéia - PI, under irrigation system in the agricultural year 2009/2010. We evaluated five plant populations (100; 200; 300; 400 and 500 thousand plants per hectare) in a randomized complete block design with four replications, using BRS Novaera. The increase in population from 100 thou- sand to 500 thousand plants ha - 1 led to reductions of 78.18% in the number of branches, 66.53% in the number of pods per plant,59.53% in grain yield and, on average,of65.76% and 72.65% for biomass and plantlet af area, respectively. The pod length and weight of on hundred seeds was not significantly influenced by different plant populations. The different plant densities promoted significant changes in morphological and physiological characteristis, yield component sand grain yield.

Three castor ( Ricinus communis ) genotypes were studied regarding tolerance to high exchange factorial distribution of five doses of exchangeable aluminum added to the soil (0, 0.15, 0.30, 0.60, and 1.20 cmol c dm - 3 ) and three castor genotypes (BRS Nordestina, BRS Paraguaçu, and Lyra). The plants were raised in pots in a greenhouse. At 53 days after emergence, data were taken on plant height, leaf area, dry mass of shoot and root, and leaf tissue content of macronutrients. The most sensitive genotype was the cv. BRS Nordestina, in which the shoot and root dry weight in the highest aluminum content were reduced to 12.9% and 16.2% of the control treatment, respectively. The most tolerant genotype was the hybrid Lyra, in which the shoot and root dry weight in the maximum content of aluminum were reduced to 43.5% and 42.7% of the control treatment, respectively.The increased exchangeable aluminum affected the leaf nutrient content, and the intensity of the response was different among cultivars. The aluminum toxicity increased N, Ca, and Mg contents and reduced on P, K, and S contents. The cv. BRS Nordestina had a drastic shoot dry weight reduction associated with an intense increment in the N leaf content. Thus, the N increment was caused by a concentration effect caused by the limited growth.

The present study was carried out to evaluate the agronomic and technological performance of common-bean crop following three straw mulch production system (sole corn, corn-Urochloa ruziziensis inter- crop and sole U. ruziziensis) and topdressing nitrogen fertilization (0, 40, 80, 120 and 160 kg ha-1 of N) in the fourth year after the no-tillage system implementation. A randomized block design, in a splitplot array, with three replications was used. The use of U. ruziziensis intercropped with maize allowed a greater straw mulch formation and a more adequate coverage of the soil surface aiming the beans cultivation in succession. The nitrogen fertilization influenced the common-bean productivity in succession to U. ruziziensis unique and maize intercropped with U. ruziziensis. The common-bean crop in succession to the straw mulch production system with U. ruziziensis allowed higher grain production and sieve yield. The grain cooking time decreased due to the rates of N used in the dry bean crop in succession of maize exclusive.

The present work studied the productivity of plant and ratoon cane in soils with different physical, chemical and mineralogical particulars submitted to phosphate fertilization. Randomized block field experi- ments were located at Japungu Distillery (Paraíba State), at Sugar Cane Experimental Station of Carpina (Pernambuco State) and at Bom Jesus Sugar Cane plant (Pernambuco State), from where Argisoils of sandy, mid and clayey textures were selected respectively. The doses of 0, 40, 80, 120, 160 and 200 kg ha - 1 P 2 O 5 were applied at the bottom of the furrow (fertilization foundation). In the subsequent ratoon cane were applied 0 and 40 kg ha - 1 P 2 O 5 (topdressing) for each of the doses applied at the planting. It was concluded in this study that the productivity of sugarcane plant was positively influenced by phosphorus fertilization planting. The ratoon cane only responded nicely to phosphorus coverage in the less weathered medium texture Argisoils; Phospho- rus fertilization of ratoon sugarcane coverage in clay and weathered Argissolos did not promote increased productivity, restricting its recommendation in Argissolos with these characteristics.

The ginger culture was planted in Espirito Santo State on a commercial scale for just over 10 years as an alternative income for farmers family based submitted high yield potential, but requires studies to their best advantage due to the great variability of climatic conditions of the State. The aim of this study was to evaluate the yield of fresh rhizomes, the dry mass of leaves and rhizomes and the extraction and accumulation of N, P and K of the culture depending on the application of increasing doses of P, in a dystrophic Ultisol . The experiment was conducted on a farm in the municipality of Santa Maria de Jetibá (ES) between the months of August 2006 and June 2007. Experimental model adopted was randomized blocks with four treatments and four replications. The treatments consisted of control (no P fertilization), and doses of 60, 120 and 240 kg ha - 1 of P 2 O 5 applied at planting. The plants showed continuous growth up to 180 days after planting (DAP) and the phase of the plant where there was greater uptake of N, P and K in the flowering cycle was at 240 DAP. Analy- zing the contents of N, P and K, in the rhizome and leaves over the cultivation cycle, it was observed that, in general, most of the accumulation occurred in the rhizome.

Considering the potential of castor beans as an alternative for the production of renewable en- ergy and the lack of information regarding management techniques for its cultivation, this study was conducted to evaluate the effect of different levels of irrigation water salinity (ECw) associated with nitrogen fertilization rates (DN) on growth, water consumption and efficiency of water use by castor bean cv. BRS Energia. The experiment was conducted in lysimeters under field conditions, atCCTA/UFCG, adopting a randomized block designin 5x5factorial scheme with three replications. Treatments consisted of five levels of ECw (0.4, 1.4, 2.4, 3.4 and 4.4 dS m-1) associated with five doses of nitrogen (50, 75, 100;125 and 150 mg kg-1). The increase in water salinity from 0.4 dS m-1 caused linear decrease in the absolute growth rate(TCAap), total leaf area(AF)at 35 days after sowing (DAS), the water consumption and water use efficiency (EUA) for castor bean cv. BRS Energia. Increasing levels of water salinity promoted increase in relative growth rate (TCRap). Nitrogen rate of 114 mg kg-1 increased TCRap and 150 mg kg-1of N promoted greater EUA. Increasing levels of nitrogen at- tenuated at 120 DAS, the effect of electrical conductivity up to salinity level of 2.4 dS m-1 on the leaf area pro- moting higher specific leaf area. There was a significant interaction between ECw and nitrogen levels on elec- trical conductivity and pH of drainage water. Keywords: Ricinus communis L. Quality of water. Mineral nutrition.