High stocking rates in intensive pasture-based animal production systems may compromise the development of the forage roots due to increased resistance in the surface layer. This study tested the hypothesis that an increase in stocking rate resulting from different levels of nitrogen fertilization in irrigated Mombaça grass (Panicum maximum Jacq. cv. Mombaça) pasture under intermittent grazing could increase resistance to penetration and consequently the growth of the root system. A split-plot design with randomized blocks and subplots was used, including three replications and the following four treatments: 0, 200, 400 and 800 kg N ha −1 year. Evaluations performed in spring, summer and fall seasons were assigned as subplots. The highest values for area, diameter, length and percentage of root biomass (91.4%) were concentrated at the 0-10 cm soil depth, which is explained by the lower penetration resistance in this layer. Increased stocking rate resulting from increased levels of nitrogen in the Mombaça grass sward does not directly affect the penetration resistance of the soil or root characteristics. However, in the rainy season, higher nitrogen levels lead to increased resistance, as they provide higher cumulative stocking rates in this period. Key words: Irrigation. Nitrogen fertilization. Panicum maximum. Soil compaction. ResumoElevadas taxas de lotação em sistemas intensivos de produção animal a pasto podem comprometer o desenvolvimento das raízes de forrageiras, devido ao aumento da resistência do solo na camada superficial. Neste estudo testou-se a hipótese que o aumento da lotação animal devido a diferentes doses de nitrogênio em pasto de capim-Mombaça (Panicum maximum Jacq. cv Mombaça), irrigado e sob pastejo intermitente poderiam comprometer a resistência à penetração e consequentemente o crescimento do sistema radicular. Utilizou-se delineamento experimental em blocos ao acaso com parcelas subdivididas, com três repetições e quatro tratamentos: 0, 200, 400 e 800 kg de N ha −1 ano. Nas subparcelas foram consideradas as quatro estações do ano. As características geométricas (área,
A B S T R A C TPoultry manure and mechanical management may influence the distribution of nutrients in the soil profile. The objective was to evaluate physical and chemical changes in a soil with palisade grass (Brachiaria brizantha cv. Marandu) fertilized with doses of poultry manure with and without use of soil chiseling, after 180 days of application. The design was a randomized blocks with four replicates, in a 5 x 2 factorial arrangement with five doses of manure (0, 1.073, 2.074, 4.148 and 6.222 Mg ha -1 ), with and without soil chiseling at 0.20 m. Soil chiseling caused physical changes with an increase of macroporosity in the layer of 0-0.2 m and reduction in soil density and increase in macroporosity and total porosity in the layer of 0.2-0.4 m. With manure doses, pH in the layer of 0-0.1 m showed quadratic fit with maximum value of 7.2. The increases in Ca and Zn in the layer of 0-0.1 m were, respectively, 0.61 cmol c dm -3 and 2.99 mg dm -3 . In the interaction of Dose x Management, without soil chiseling, K showed a linear fit and increased 1.39 times; while in the interaction of Dose x Management, with soil chiseling in the layers of 0.1-0.2 and 0.2-0.4 m, P increased by 8.10 and 3.95 mg dm -3 , respectively. In the contrast between the dose zero and manure dose, there was significance for pH, Ca, P and Zn in the layer of 0-0.1 m.Alterações físicas e químicas em solo fertilizado com esterco de galinha em diferentes manejos R E S U M O O esterco de galinha e o manejo mecânico podem influenciar na distribuição de nutrientes no perfil do solo. O objetivo foi avaliar as alterações físicas e químicas no solo com capim Marandu fertilizado com doses de esterco de galinha sem e com uso de escarificador, após 180 dias de aplicação. O delineamento foi em blocos ao acaso com quatro repetições num arranjo fatorial 5 x 2, com cinco doses de esterco (0, 1,037; 2,074; 4,148; 6,222 Mg ha -1 ) sem e com escarificação a 0,20 m. A escarificação favoreceu alterações físicas com aumento de macroporosidade na camada 0-0,2 m e redução de densidade do solo e aumento de macroporosidade e porosidade total na camada 0,2-0,4 m. Com doses de esterco o pH na camada 0-0,1 m teve ajuste quadrático com valor máximo de 7,2. O aumento nos teores de Ca e Zn na camada 0-0,1 m foi, respectivamente, de 0,61 cmol c dm -3 e de 2,99 mg dm -3 . Na interação dose x manejo sem escarificação do solo o K teve ajuste linear com aumento de 1,39 vezes enquanto na interação entre dose x manejo com escarificação nas camadas 0,1-0,2 e 0,2-0,4 m, o P teve aumento de 8,10 e 3,95 mg dm -3 , respectivamente. No contraste entre dose zero com dose de esterco houve significância para pH, Ca, P e Zn na camada 0-0,1 m.
-The objective of this study was to determine effects of the addition of calcium salts of fatty acids (CSFA) to the concentrate on the intake and digestibility of dry matter and nutrients and the grazing behavior of lactating Saanen goats. Five multiparous goats in their third lactation and four primiparous goats were used. The animals were distributed into two Latin square designs, which, for the multiparous goats was 5 × 5, with five treatments (0%, 1.5%, 3.0%, 4.5%, and 6.0% CSFA); and for the primiparous goats was 4 × 4, with four treatments (0%, 1.5%, 3.0%, and 4.5% CSFA). The addition of CSFA to the concentrate of lactating Saanen goats did not influence the time spent grazing, ruminating, or lying for multiparous goats. However, for primiparous goats, for the time spent grazing, there was a negative quadratic effect with the addition of CSFA to the concentrate. The treatments did not affect the intakes of dry matter, organic matter, crude protein, neutral detergent fiber, total carbohydrates, non-fiber carbohydrates, or total digestible nutrients for multiparous goats. No effects were observed on nutrient digestibility, except for crude protein and the ether extract, which increased the energy values of the diets with 3.5% CSFA. For primiparous goats, no effects were observed on intake or digestibility. Addition of CSFA can be used as an alternative to feed primiparous goats in grassland when the grazing time is a factor limiting intake. Addition of up to 3.5% of CSFA increases the energy value of diets for multiparous goats. These results suggest that calcium salts of fatty acids is an alternative energy supplement to feed lactating goats.
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