Year-round PoultrY litter decomPosition and n, P, K and ca release summarY Poultry litter is an important nutrient source in agriculture, although little information is available regarding its decomposition rate and nutrient release. to evaluate these processes, poultry litter (Pl) was applied to the soil to supply 100, 200 and 300 kg ha -1 n contained in 4,953, 9,907 and 14,860 kg ha -1 Pl, respectively. the litter bag technique was used to monitor the process of decomposition and nutrient release from the litter. these bags were left on the soil surface and collected periodically (after 15, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330, and 365 days). the dry matter (dm) loss was highest (35 %) after the first 30 days of field incubation. the highest nutrient release occurred in the first 60 days on the field, when 40, 34, 91, and 39 %, respectively, of n, P, K, and ca of the initial Pl dry matter (4,860 kg ha -1 ) was already released to the soil. in absolute terms, these percentages represent 40, 23, 134, and 69 kg ha -1 of n, P, K, and ca and these values doubled and tripled as the Pl fertilization rates increased to 9,907 and 14,860 kg ha -1 , respectively. after one year of field incubation, the residual contents in the litter were 27, 15, 18 and 30 % of the initial dm , and n, P and ca, respectively. the release rate of K was the fastest and 91 % of the K had been released from the Pl after 30 days of field incubation. index terms: litter bag, filed incubation, organic fertilizer, residual contents.

No abstract

Pattern classification of ingestive behavior in grazing animals has extreme importance in studies related to animal nutrition, growth and health. In this paper, a system to classify chewing patterns of ruminants in in vivo experiments is developed. The proposal is based on data collected by optical fiber Bragg grating sensors (FBG) that are processed by machine learning techniques. The FBG sensors measure the biomechanical strain during jaw movements, and a decision tree is responsible for the classification of the associated chewing pattern. In this study, patterns associated with food intake of dietary supplement, hay and ryegrass were considered. Additionally, two other important events for ingestive behavior were monitored: rumination and idleness. Experimental results show that the proposed approach for pattern classification is capable of differentiating the five patterns involved in the chewing process with an overall accuracy of 94%.

-The objective of this work was to evaluate the influence of different grazing periods on beef animal production and on wheat forage and grain yield. The experiment was carried out in Pato Branco, PR, Brazil. Six grazing periods were evaluated (0, 21, 42, 63, 84, and 105 days) on dual-purpose wheat cultivar BRS Tarumã. Purunã steers, with average live weight of 162 kg and ten months of age, were kept under continuous grazing using a variable stocking rate, in order to maintain the established sward height of 25 cm. Greater increases in total animal gain (TAG) occurred with longer grazing periods. However, there was little increase after 63 days (490 kg ha -1 ), and TAG decreased from 552 to 448 kg ha -1 between 84 and 105 days. Grain yield decreased from 2,830 to 610 kg ha -1 when the grazing period increased from 0 to 105 days, but there was little change after 63 days (750 kg ha -1 ). Cultivar BRS Tarumã shows excellent animal production potential, and the decision on how long wheat pastures should be grazed must be based on relative prices of grain and livestock.Index terms: Triticum aestivum, 'BRS Tarumã', forage mass, nutritive value, Purunã steers, weight gain. Produção animal e de grãos de trigo duplo propósito em diferentes períodos de pastejoResumo -O objetivo deste trabalho foi avaliar a influência de diferentes períodos de pastejo na produção de carne bovina, de forragem e de grãos de trigo. O experimento foi conduzido em Pato Branco, PR. Foram avaliados seis períodos de pastejo (0, 21, 42, 63, 84 e 105 dias) com a cultivar de trigo de duplo propósito BRS Tarumã. Novilhos Purunã, com peso vivo médio de 162 kg e idade de dez meses, foram mantidos em pastejo contínuo, com taxa de lotação variável, para manter a altura de pastejo estabelecida de 25 cm. Maior ganho animal por área (GA) foi encontrado em períodos mais longos de pastejo. No entanto, houve pouca diferença após 63 dias (490 kg ha -1 ), e o GA diminuiu de 552 para 448 kg ha -1 , entre 84 e 105 dias. A produtividade de grãos diminuiu de 2.830 para 610 kg ha -1 com o aumento do período de pastejo de 0 para 105 dias, mas mudou pouco após 63 dias (750 kg ha -1 ). A cultivar BRS Tarumã apresenta excelente potencial para a produção animal, e a decisão quanto ao período de utilização do trigo para pastejo deve ser baseada nos preços relativos de grãos e dos animais.Termos para indexação: Triticum aestivum, 'BRS Tarumã', massa de forragem, valor nutritivo, novilhos Purunã, ganho de peso.

SUMMARYNitrogen usually determines the productive potential of forage crops, although it is highly unstable in the environment. Studies on recovery rates and use efficiency are important for more reliable fertilizer recommendations to reduce costs and avoid environmental pollution. The purpose of this study was to evaluate N use efficiency and recovery rate of Alexandergrass pasture (Brachiaria -Syn. Urochloa plantaginea) as well as N-NO 3 -and N-NH 4 + soil concentrations using different levels of N fertilization under two grazing intensities. The experiment was arranged in a randomized block design in a factorial scheme with three replications. Treatments consisted of three N rates (0, 200 and 400 kg ha -1 N) and two grazing intensities termed low mass (LM; forage mass of 2,000 kg ha -1 of DM) and high mass (HM; forage mass of 3,600 kg ha -1 of DM) under continuous stocking and variable stocking rates. Results of N fertilization with 200 kg ha -1 were better than with 400 kg ha -1 N. There was a significant effect of N rates on soil N-NO 3 -concentration with higher levels in the first layer of the soil profile in the treatment with 400 kg ha -1 N. Grazing intensity also affected soil N-NO 3 -concentration, by increasing the levels under the higher stocking rate (lower forage mass).