No abstract

ABSTRACT:Composting is a useful way of transforming livestock waste into organic fertilizer, which is proven to increase soil nutrient levels, and thus crop yield. Remains from production and slaughter of small ruminants can become a source of important elements for plant growth, such as N, after microorganism-driven decomposition.The aim of this investigation was to evaluate the effects of this compost on soil fertility and on the nutritional status and yield of the corn crop. The experiment was conducted in a Haplic Luvisol in a randomized block design with six treatments and five application rates of the organic compound in Mg ha -1 : 3 (half the standard rate), 6 (standard rate), 9 (one and a half times the standard rate), 12 (twice the standard rate), and 24 (four times the standard rate) and an additional treatment with mineral fertilizers (110, 50 e 30 kg ha -1 of N, P 2 O 5 and K 2 O, respectively), with four blocks. Evaluations were performed for two harvests of rainfed crops, measuring soil fertility, nutritional status, and grain yield. The compost increased P, K, Na and Zn values in the 0.00-0.20 m layer in relation of mineral fertilization in 616, 21, 114 and 90 % with rate 24 Mg ha -1 in second crop. Leaf N, Mg, and S contents, relative chlorophyll content, and the productivity of corn kernels increased in 27, 32, 36, 20 e 85 %, respectively, of low rate (3 Mg ha -1 ) to high rate (24 Mg ha -1 ) with of application of the compost. Corn yield was higher with application of organic compost in rate of 24 Mg ha -1 than mineral fertilizer combination in second crop.

The identification of superior genotypes in plant breeding programs is not a quick and simple task and requires breeders to become aware of more suitable and efficient tools for evaluating crop performance. Univariate analyses are often too narrow for the scope of plant breeding because it lacks consideration of relations between variables. Therefore, the objective of this study was to select castor bean hybrids based on principal component analysis (PCA). Trials were conducted in 2017 with 31 hybrids in a randomized block design with 4 replications. The following variables were used to evaluate crop performance: plant height (PH), insertion height of the primary raceme (HPR), number of stem nodes (NN), number of racemes (NR), number of seeds (NS), stem diameter (SD), number of fruits (NF), 100-seed weight (S100) and seed oil content (SOC). The first three principal components (PCs) explained approximately 75.01 % of all the variability in the dataset. PC 1, 2 and 3 were particularly related to productivity (NS, NR, S100 and NF), plant size (SD, HPR and PH) and oil production (SOC), respectively. Hybrids 14 and 23 were the most suitable for grain production in commercial scale due to short-height, which favors mechanical harvesting. Commercial hybrid 26 showed high SOC, medium grain yield and medium-height.

Resumo: O uso de compostos orgânicos é alternativa interessante como destino de subprodutos, sendo que para resíduos da pecuária, como a carcaça e restos de abatedouro, em que a geração de fertilizante orgânico permite a ciclagem de nutrientes, assim, objetivou-se a avaliar os efeitos do uso do composto orgânico proveniente de resíduos da produção e abate de caprinos e ovinos no crescimento e acúmulo de nutrientes de mudas de gliricídia. O experimento foi conduzido em casa de vegetação, com cinco doses de composto orgânico oriundo de resíduos da produção e abate de pequenos ruminantes adicionado no substrato em diferentes proporções (0, 10, 20 30 e 40%). Os tratamentos com cinco repetições foram distribuídos em delineamento experimental inteiramente casualizado, com três mudas por parcelas. As avaliações foram procedidas 90 dias após germinação das sementes, quando foram avaliados os parâmetros biométricos, biomassa relação massa seca da parte aérea e massa seca da raiz, índice de qualidade de Dickson, acúmulo de nutrientes nas mudas e taxa de recuperação. Todos os parâmetros biométricos e de biomassa foram afetados significativamente, com exceção da altura. A ordem decrescente de macro e micronutrientes acumulados em mudas de gliricídia foi de N>K>Ca>Mg>S>P e Fe>Mn>B>Zn>Cu, respectivamente. A taxa média de recuperação de nutrientes em mudas de gliricídia foram de 13