The intensive cultivation of vegetables with frequent chemical fertilization may cause accumulation of nutrients in the soil. This, in turn, may reduce crop yields and damage the environment due to contamination of ground water and rivers. Thus, to increase the effects of P (0, 100, 200, 300 and 400 kg ha - 1 of P 2 O 5 ) and K (0, 60, 120, 180 and 240 kg ha - 1 of K 2 O) doses on the growth and productivity of radish cultivars (Sakata 19 and Sakata 25) in a soil with high levels of these nutrients, two experiments were conducted in randomized blocks with the factors cultivars and doses arranged in a 2 x 5 factorial design with three replications. Number of leaves per plant, leaf area, shoot and root dry mass, total and commercial productivity, percentage of cracked roots and P and K contents in the plant and in the soil were evaluated. The Sakata 19 cultivar performed better than the Sakata 25 in both experiments. The fertilization with P or K did not influence the growth and the productivity of both radish cultivars. Therefore, both cultivars of radish evaluated do not need to be fertilized with P and K when planted in a Latosol with high levels of these nutrients.

In flood plains, cover crops are able to alter soil properties and significantly affect rice nutrition and yield. The aims of this study were to determine soil properties, plant nutrition, and yield of tropical rice cultivated on flood plains after cover crop cultivation with conventional tillage (CT) and no-tillage system (NTS) at low and high nitrogen (N) fertilization levels. The experimental design was a randomized block in a split-split-plot scheme with four replications. In the main plots were cover crops sunhemp (Crotalaria juncea and C. spectabilis), velvet bean (Mucuna aterrima), jackbean (Canavalia ensiformis), pigeon pea (Cajanus cajan), Japanese radish (Raphanus sativus), cowpea (Vigna unguiculata) and a fallow field. In the subplots were the tillage systems (CT or NTS). The nitrogen fertilization levels in the sub-subplots were (10 kg N ha-1 and 45 kg N ha-1). All cover crops except Japanese radish significantly increased mineral soil nitrogen and nitrate concentrations. Sunhemp, velvet bean, and cowpea significantly increased soil ammonium content. The NTS provides higher mineral nitrogen and ammonium content than that by CT. Overall, cover crops provided higher levels of nutrients to rice plants in NTS than in CT. Cover crops provide greater yield than fallow treatments. Rice yield was higher in NTS than in CT, and greater at a higher rather than lower nitrogen fertilization level.

The objective of this work was to evaluate seeds of cowpea, cultivar BRS Tumucumaque, subjected to different water stresses induced by polyethylene glycol (PEG-6000) and mannitol and different salt stresses induced by NaCl and CaCl2 solutions. The water and salt stresses was evaluated in laboratory using completely randomized experimental designs in 2x6 factorial arrangements, with six osmotic potentials (0.0, -0.2, -0.4, -0.6, -0.8 and -1.0 MPa) and two stress inducers for each experiment, with four replications of 50 seeds. The percentage of germination, germination speed index, root and shoot lengths and seedling fresh weight were evaluated at the tenth day (end of the evaluation period). The simulated water stress showed effects on the cowpea seed germination and seedling initial growth by decreasing the rates of the variables evaluated, which had greater effect in treatments with PEG-6000. The salt stress induced by NaCl showed greater effect on the variables evaluated than that induced by CaCl2, due to the sodium toxicity in the salt chemical composition.

Uncontrolled weed growth interferes with the growth eggplants and crop yields. To control weeds, the main weed species must be identified in crop growing areas and during weed control periods, as weed species might vary in relation to management practices. Therefore, this study aimed to identify the main weed species and determine the periods of weed interference in the eggplant cultivar Nápoli when grown under certain cultural practices, including plant staking and sprout thinning. The experiment was carried out in 2014 using a randomized complete block design, with 3 replications. The treatments consisted of 11 periods of (1) increasing weed control and (2) increasing coexistence of eggplant with weeds from the first day of transplanting (0-14, 0-28, 0-42, 0-56, 0-70, 0-84, 0-98, 0-112, 0-126, 0-140, and up do day 154). Eggplant staking and sprout thinning were performed 42 days after transplanting (DAT). Weed identification and crop yield assessments were performed to determine the Period Before Interference (PBI), Total Period of Interference Prevention (TPIP), and the Critical Period of Interference Prevention (CPIP). The major weeds found in the eggplant cultivar Nápoli were Eleusine indica, Portulaca oleracea, and Cyperus rotundus. Coexistence between the weed community and the eggplant throughout the entire crop production cycle reduced eggplant fruit yield by 78%. The PBI was 29 DAT and the TPIP was 48 DAT, resulting in 19 days of CPIP.

This study aimed to evaluate the performance, carcass yield and intestinal morphometry of 1- to 21-day-old broiler chickens fed a diet containing increasing levels of sunflower cake, supplemented with or without an enzyme complex (EC). We used 1200 Cobb 500 birds, which were distributed in a completely randomized design in a 2x5 factorial scheme and five levels of sunflower cake inclusion (0, 5, 10, 15, and 20%) in diets supplemented or not with EC. Each treatment consisted of 5 replicates. Animals were fed the experimental diets from 1 to 21 days of age and from 22 to 42 days all birds received the same feed based on corn and soybean meal. There was no interaction between the level of sunflower cake inclusion and presence of EC. From 1 to 21 days of age, the weight gain, final weight, and feed intake linearly decreased (P<0.05) with increasing sunflower cake inclusion level. At 42 days old, after animals consumed diets based on corn and soybean meal (from 22 to 42 days), the levels provided least 21 days did not influence the performance results. Animals receiving the EC in the first phase showed better results at the end of the experiment (P<0.05). Up to 21 days old, carcass yield decreased, and abdominal fat increased with the sunflower cake inclusion. The addition of EC in the diet improved the thigh, breast and carcass yield. Intestinal morphology after 21 days revealed that the three segments of the intestine had at least one type of change, such as a decrease in villus height and increase in crypt depth, with increased level of sunflower cake in the diet, affecting performance.

The use of chemical seed treatment is an important tool in the protection of seedlings and has contributed to the increase of rice yield (Oryza sativa L.). The objective of this study was to evaluate the physiological quality and quantify the retention of chemical products in rice seeds treated with insecticide and fungicide coated with polymers. Six seed treatments were used: control, phytosanitary treatment and phytosanitary treatment and coating with the polymers, Florite 1127®, GV5® Solid Resin, Polyseed CF® and VermDynaseed®. The physiological quality was evaluated by the test of germination and vigor by first count tests, germination speed index, shoot length, radicle length, seedling dry mass and sand emergence. To determine the retention of the active ingredients metalaxyl-M and thiamethoxam, an equipment called extractor was used. The experiment was organized in a completely randomized design (DIC) and the averages were separated by the Scott Knott test (p≤0.05). Seed treatment with the fungicide and insecticide, coated with the polymers, Florite 1127®, Solid Resin GV5®, Polyseed CF® and VermDynaseed®, did not affect the physiological quality of rice seeds. Solid Resin GV5®, Polyseed CF® and VermDynaseed® polymers were efficient at retaining thiamethoxam in the rice seeds, preventing some of the active ingredients of the insecticide from being leached through the sand columns immediately after the simulated pluvial precipitation.

The effects of biochar and nitrogen application on yields of upland rice and cowpea and on soil fertility were determined in a greenhouse in Macaíba, RN, Brazil. The trial consisted of the succession of two crops in a completely randomized design and a factorial scheme, with four replicates. Initially, four doses of biochar and four doses of nitrogen were tested for cultivation of rice. Subsequently, four doses of biochar and two doses of nitrogen were tested in half of the pots maintained for planting cowpea. Soil was sampled after rice harvest for half of the pots and at end of the trial for the remaining pots. We evaluated the following parameters: mass of hundred grains of rice, dry shoot mass, panicle number, number of filled spikelets and of empty spikelets, and grain production. Determinations for cowpea were: pod number per pot, grain number per pod, and grain production per pot. Measured soil parameters were: pH, contents of organic carbon, P, K, Ca, Mg, Na, cation exchange capacity, and exchangeable sodium percentage. Biochar addition did not influence yield components of upland rice and cowpea, but resulted in increased soil N retention, which influenced rice dry shoot mass, spikelets sterility, panicle number, and grain mass. Biochar also promoted increased soil pH, potassium content, and exchangeable sodium percentage and decreased calcium and magnesium concentrations.

The effects of biochar and nitrogen application on yields of upland rice and cowpea and on soil fertility were determined in a greenhouse in Macaíba, RN, Brazil. The trial consisted of the succession of two crops in a completely randomized design and a factorial scheme, with four replicates. Initially, four doses of biochar and four doses of nitrogen were tested for cultivation of rice. Subsequently, four doses of biochar and two doses of nitrogen were tested in half of the pots maintained for planting cowpea. Soil was sampled after rice harvest for half of the pots and at end of the trial for the remaining pots. We evaluated the following parameters: mass of hundred grains of rice, dry shoot mass, panicle number, number of filled spikelets and of empty spikelets, and grain production. Determinations for cowpea were: pod number per pot, grain number per pod, and grain production per pot. Measured soil parameters were: pH, contents of organic carbon, P, K, Ca, Mg, Na, cation exchange capacity, and exchangeable sodium percentage. Biochar addition did not influence yield components of upland rice and cowpea, but resulted in increased soil N retention, which influenced rice dry shoot mass, spikelets sterility, panicle number, and grain mass. Biochar also promoted increased soil pH, potassium content, and exchangeable sodium percentage and decreased calcium and magnesium concentrations.

This study aimed to characterize and select silk blossom genotypes (Calotropis procera) with forage potential. Between April and July 2014, we cultivated 89 genotypes in plastic tubes arranged in a randomized block design with three replications; each experimental plot was composed of 8 plants. The following characteristics were evaluated: plant height (PH), stem diameter (SD), number of leaves (NL), total leaf area (TLA), leaf fresh mass (LFM), stem fresh mass (SFM), root fresh mass (RFM), leaf dry mass (LDM), stem dry mass (SDM), and root dry mass (RDM). Significant differences (p < 0.05) among genotypes were observed for all characteristics, except for NL at 45 and 60 days after sowing (DAS) and for RFM at 60 DAS. Broad-sense heritability estimates and genotype means had medium and high values for most characteristics. Genetic variability among C. procera genotypes was observed. High gain selection was found for the characteristics TLA, PH, SFM, LFM, SDM, and LDM as the genotypes 79, 65, 48, 12, 51, 35, 63, 25, 1, and 46 are suitable for future breeding works to improve forage production.

The production of vegetable crops is characterized by intensive land use, high input demands and the requirement of strategic management adoption with an agro - ecological approach. In this study, agronomic indicators were evaluated in lettuce fertilized with different amounts of roostertree biomass; fertilizer was incorporated into the soil at distinct times and seedlings were planted in two cropping seasons (spring and autumn - winter) in Serra Talhada, Pernambuco state, Brazil. The experimental design consisted of randomized complete blocks with three replications and treatments arranged in a 4 x 4 factorial scheme. The first factor was the amounts of roostertree biomass (5.4, 8.8, 12.2, and 15.6 t ha - 1 on a dry basis) and the second the manure incorporation times (0, 10, 20, and 30 days before lettuce transplanting). The variables evaluated in the lettuce crop were: plant height and diameter, number of leaves per plant, productivity of green mass, and dry shoot mass. Maximum productivity and dry shoot mass were obtained using fertilization with 15.6 t ha - 1 . A synchrony between supply of nutrients by green manure and the period of maximum demand by lettuce was observed in the incorporation times of 10 (spring) and 20 (autumn - winter) days before transplanting. Cultivation in the spring resulted in higher vegetative growth.