The objective of this work was to study the effects of N and K2O doses applied through fertigation in soil fertility and nutritional status. The experiment was carried out during April, 2002 until March 2004, on Experimental Farm of the Empresa de Pesquisa Agropecuária of the State of Rio Grande do Norte (EMPARN), Brazil. The statistical design was in a completely randomized block with 4 replication, using for composition of treatments Plan Puebla III experimental matrix, treatments being composed of combination of two factors: nitrogen and potassium doses in the form of urea and potassium chloride, respectively. In all 10 treatments, defining the interval for N (256 to 4874 g plant-1 year-1) and K2O (258 to 4872 g plant-1 year-1) were applied through fertigation with microsprinkler irrigation system. The contents of nutrients in the soil presented great variation and tended to decrease with time. The doses of N decreased the pH and contents of Ca and Mg although increased the availability of P in soil and favored its absorption by plant. A negative gradient in concentration of nutrients under fertigation was observed from the soil surface. The K content in leaf 14 were increased with increase in doses of K2O via fertigation presenting high correlation with number of fruits. The application of K in soil increased the contents of Cl and Mg in leaf 14 and decreased the contents of Na, while the application of N in soil increased the contents of Mn in leaves.

The process of production of Biodiesel Directly Seed (PDS) of oil using a catalyst based on NaOH in the transesterification reaction. The primary byproduct of this process is the pie PDS, this presents considerable levels of sodium in their composition, which can be limiting in the activity of microorganisms during mineralization. The aim of this study was to evaluate the mineralization rate of castor bean cake pro- duced from the direct process of the seed (PDS), added to soil samples collected at a depth of 0 - 20 cm of a Typic Eutrophic (CXbe) located in the area of the Apodi Plateau, Rio Grande do Norte, Brazil. The castor bean used were from the Experimental Station of Biodiesel (UEB - 2), Research Center Leopoldo Americo Miguez de Mello, Guamaré, RN. For the study was used castor bean in fresh state and treated with distilled water to re- move the Na + . The material was incubated in increasing leaves of castor bean PDS 0, 5, 10, 20, 40, 80 and 160 mg ha - 1 for a period of 32 days. Was evaluated the decomposition of the material through the evolution of CO 2 . The mineralization rate of the pie PDS castor in a Cambisol is not influenced by sodium levels present in in natura and treated pie. The treatment with pie PDS water is effective in reducing the levels of total and ex- changeable sodium, but as a result there are losses of N and K.

The fall armyworm is a pest that feeds on various botanies species. The objective of this experi- ment was to study the biology of this pest in corn and cassava leaves. Caterpillars were collected in area under cultivation with cassava and maintained on artificial diet for two generations. Under controlled conditions in a climatic chamber (B.O.D) in the laboratory (25 ºC, 60 ± 10% RH and photophase 14 hours) were evaluated daily 50 caterpillars in corn treatments and 50 in cassava, where duration and viability of the larval phase and pupal, weight of pupas were observed after 24 hours, deformation percentage of pupas and adults, longevity, fecundity and total life cycle. The viability of larvae fed on leaves of maize and cassava was 74% and 60%, respectively. The larval period of the insects was shorter in maize 16.89 days (seven instars) and cassava 20.08 days (six instars). The pupal phase lasted 11.42 days in cassava treatment and 10.87 in the maize. The pupal weight of females and males was higher in corn 204.91 mg and 198.97 mg, respectively. The biological cycle varied depending on the ingested food. Adult longevity lasted 9.88 days for insects fed on cassava leaves. Therefore, cassava affected the development of S. frugiperda.

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 aim of this study was to evaluate the performance of varieties of common bean in notillage on biomass of fallow vegetation as a function of crop fertilization. The study was conducted at Bujari, AC. The experimental design was a randomized complete block split plot with four replications. The experiment consisted in the cultivation of three varieties of common bean in no-tillage on weed straw, with and without fertilization at planting subplot. The variables analyzed were grain yield, final stand, number of pods per plant, number of grains per pod and weight of hundred grains. The data were submitted to the F test and means were compared by Tukey test (p<0,05). The bean variety Carioca Pitoco has better grain yield than the Carioca and Rosinha varieties on the first year of no-tillage system. The crop fertilization increases the yield of varieties of beans grown on straw till the fallow vegetation.

The silicon fertilization has a beneficial effect in enhancing the resistance of plants to diseases, however, this effect can be reduced in the presence of high levels of nitrogen. Given the above, this study aimed to investigate the effect of silicated and nitrogen fertilization in control of rice blast in irrigated system. Plants were grown in an area of tropical lowland and evaluated as to the severity of leaf blast incidence on pan-1 of calcium and magnesium silicate associated with 45 kg ha - 1 of nitrogen topdressing on had lower severity of leaf blast and higher grain yield compared to plants not supplemented with silicon. The combination of silicated fertilization with 90 kg ha - 1 of nitrogen topdressing resulted in a greater incidence of panicle rice blast. After analyzing the results, it was concluded that supple- mentation with silicon and nitrogen promoted reduction in the severity of blast in rice plants in irrigation sys- tem without affecting the yield.

The fruits and seeds of tucumã-of-Goiás have important nutritional properties and are used in human consumption and feed. Thus, the study of the thermodynamic properties in the drying process is critical to project analysis equipment, preservation and packaging process of seeds. The aim of this study was to determine and evaluate the thermodynamic properties for different hygroscopic moisture contents of seeds tucumãof- Goiás. For the experimental data we used the static indirect at temperatures of 10, 20, 30 and 40 °C and moisture content of 12.8; 8.9; 5.8 and 3.6% dry base (d.b). The model Copace was that got the best fit to hygroscopic equilibrium moisture content. The thermodynamic properties are affected by moisture content, and the latent heat of vaporization of water from the seeds increases with the decrease in the equilibrium moisture content ranging from 3049.00 to 2666.73 kJ kg-1 for moisture content of 3.6 to 12.8% d.b., respectively. The enthalpy and differential entropy are strongly related to the moisture content of seeds. The isokinetic temperature of 210.93 K confirms the chemical linear compensation between differential entropy and enthalpy seeds of tucumã-of-Goiás, the desorption process being controlled by the enthalpy of seeds.

The study was conducted to evaluate the intake, digestibility, production and composition of milk from goats fed with diets containing different protein sources (soybean meal, cottonseed cake, aerial part cassava hay, leucaena hay). Were used eight goats with 96.5 ± 3.7 days in lactation, producing 2.0 ± 0.44 kg of milk and with an average initial weight of 47.5 ± 6.6 kg distributed in two Latin square 4 x 4. The animals fed the diet containing aerial part cassava hay presented (P<0.05) higher intake of rumen undegradable protein and an intake neutral detergent fiber corrected for ash and protein higher than (P<0.05) the diet with soybean meal. The use of cottonseed cake as protein source have provided (P<0.05) intake of rumen degradable protein and ether extract higher than the remaining diets. The nutrient digestibility, production and milk composition were similar (P>0.05) between the protein sources evaluated. The efficiency of nitrogen utilization and secretion of urea in milk presented significant effect (P<0.05) in that diet with aerial part cassava hay had lower average compared to the diet with soybean meal. Diets containing soybean meal, cottonseed cake, aerial part cassava hay or leucaena hay can be used as a protein source in diets for lactating goats, not to change the digestibility of nutrients or interfere with the production and composition of milk.

Organic fertilizing promotes changes in the physical, chemical and biological attributes of soil making it more productive. The objective of this study was to evaluate the effect of different amounts of hairy woodrose (Merremia aegyptia L.) and their times of incorporation on the chemical attributes of an Alfissol Eutrophic cultivated with lettuce. The experiment was conducted from April to June 2006 at the Universidade Federal Rural do Semi-Árido (UFERSA) in Mossoró-RN. The experimental design was complete randomized blocks with treatments arranged in a 4 x 4 factorial with 3 replications. The first factor consisted of four amounts of hairy woodrose incorporated into the soil (2.2, 4.4, 6.6 and 8.8 t ha-1 dry matter) and the second factor was the four times of their incorporations (0, 10, 20 and 30 days before transplanting lettuce). The soil pH remained alkali, decreasing with the amounts of hairy woodrose incorporated into the soil and with the times of incorporation. The contents of N, Ca and Mg in the soil increased with increasing amounts of hairy woodrose and with the times of incorporation in soil. The levels of available P and K increased with increasing amounts of hairy woodrose incorporated into the soil. However, in relation to the incorporation times, they were optimized at 16 and 14 days, respectively, after the manure incorporation. The utilization of hairy woodrose as organic fertilizer, generally, indicated improvement in soil chemical attributes in relation to the original values evaluated before its incorporation.

Aiming to evaluate the sorghum intercropping on the line in two seeding dephts of brachiaria species, a trial was conducted on the field in february 2009 in Rio Verde, GO. The experimental design used was randomized blocks in factorial scheme 2x3+1+3, with four replications, being made up two brachiaria sowing depths (2 and 10 cm), three brachiaria species (Brachiaria decumbens, B. brizantha cv. Marandu and B. ruziziensis) intercropped with the sorghum DKB 599, plus four additional treatments of sorghum and brachiaria monocultures. At 52 days after to harvest the sorghum grains, it was made up the cutting on brachiaria at 30 cm from the soil to explore the regrowth of plants in off-season cultivation, and further evaluation of forage yield at 36 days after the cutting. The intercropping in the line with B. brizantha, at 2 or 10 cm sowing depth, and with B. decumbens, sown at 2cm, appeared as the most promising for sorghum grain production. The brachiaria and sorghum intercropping in the line increased the total dry matter and crude protein yields. The regrowth of brachiaria plants in the intercropping showed to be a technique viable for forage production and soil cover in dry season at Brazil cerrado.