Stargrass (Cynodon nlemfuensis Vanderyst) is an important tropical forage, but the interaction of stocking rate (SR) and N fertilizer rate on stargrass pastures is not well understood. The objective was to determine the effects of three SR (2.5, 5.0, and 7.5 bulls ha−1) and three N rates (112, 224, and 336 kg ha−1 yr−1) on stargrass pasture characteristics and performance of Jamaica Red Poll (Bos taurus × B. indicus) weanling bulls at St. Ann, Jamaica. Soil was a bauxitic clay loam, and pastures were rotationally stocked (7‐d grazing and 21‐d rest period). Pregraze herbage mass increased as SR decreased (2.0‐4.8 Mg ha−1 in Year 1 and 3.3‐8.3 Mg ha−1 in Year 2). Herbage crude protein (CP) and in vitro digestible organic matter (IVDOM) generally increased with increasing SR and N rate. Bull daily gain decreased curvilinearly from 0.70 to 0.26 kg in Year 1 and 0.65 to 0.35 kg in Year 2 as SR increased from 2.5 to 7.5 head ha−1 Daily gain increased linearly as N rate increased from 112 to 336 kg ha−1 The N fertilizer rate had little effect on gain per hectare at the lowest SR, but gain increased with fertilization up to 224 kg N ha−1 for a SR of 5 head ha−1 and up to 336 kg N ha−1 for a SR of 7.5. In conclusion, economic return from N fertilization of stargrass pastures is dependent upon SR, with greater N rates more likely to be profitable if SR is high.
Mass and energy exchanges with the atmosphere were compared in two soybean (Glycine max L. Merr. cv. Harosoy) isolines differing in pubescence density. The study was conducted in a field with a Sharpsburg silty clay loam soil (fine, montmorillonitic, mesic Typic Argiudoll) during the summer of 1980 at Mead, Nebr. Mass and energy exchanges were determined by means of micrometeorological techniques. Evapotranspiration (reported in terms of latent heat flux) was reduced in the densely pubescent isoline. Canopy CO 2 exchange was unchanged on a per unit land area basis. Water use efficiency (reported in terms of the CO 2-water flux ratio) was, accordingly, greater in the densely pubescent isoline. The increase in pubescence did not significantly alter the net radiation balance, turbulent mixing, canopy CO 2 exchange, or plant water status. Observed differences in the partitioning of net radiation into latent and sensible heat can be explained by greater penetration of solar radiation into the densely pubescent canopy. Leaf pubescence appears to alter the spectral characteristics of the leaf and, thus, to facilitate the penetration of solar radiation into the canopy.________
‘Florigraze’ and ‘Arbrook’ are the most widely used cultivars of rhizoma peanut (Arachis glabrata Benth.), but performance of ruminants grazing these cultivars has not been compared. The objective of this study was to determine sward characteristics and performance of Holstein replacement heifers (Bos taurus) on continuously stocked pastures of Florigraze and Arbrook growing on a loamy, siliceous, hyperthermic Grossarenic Paleudult soil. Herbage mass and allowance did not differ between cultivars during 3 yr of grazing and averaged 2840 kg DM ha−1 and 2.25 kg of forage kg−1 of animal live weight, respectively. Percentage of Arbrook in pasture herbage mass decreased from Year 1 (89%) to Year 3 (66%), while percentage of Florigraze remained relatively constant (90 to 87%). Average herbage crude protein (CP) concentration and in vitro organic matter digestibility (IVOMD) were greater in Florigraze than in Arbrook (177 vs. 161 g kg−1 and 705 vs. 661 g kg−1, respectively). Average stocking rate varied little between cultivars, and animal performance was generally similar until Year 3. With a much lower percentage of rhizoma peanut in herbage mass for Arbrook than Florigraze pastures in Year 3, average daily gain (ADG; 701 vs. 516 g) and gain ha−1 (575 vs. 418 kg) were greater for heifers grazing Florigraze than for those grazing Arbrook. Florigraze appears better suited for pasture programs with continuous stocking, primarily because of superior persistence, leading to greater animal performance with time.
El objetivo del estudio fue conocer la percepción de los productores de Mezcalapa, Chiapas, sobre la influencia de los factores: personal, sociocultural, apoyos gubernamentales y de instituciones académicas, en la adopción de los sistemas silvopastoriles (SSP). Se aplicó un cuestionario semi-estructurado a 23 productores, cuyas respuestas se verificaron en campo. El análisis mediante SPSS resultó en tres conglomerados con niveles alto, medio y bajo de desarrollo. Hubo diferencia (P<0.05), respecto a la superficie cubierta de los SSP tecnificados (ha) y los metros lineales de cerco vivo por hectárea, entre los tres niveles del índice de desarrollo de los SSP (IDESSP) (P<0.05). En promedio, el 71 % de los productores considera saber regular o poco sobre los SSP. El 86 % de ellos opinó que las generaciones más jóvenes no tienen interés ni apego al campo. El apoyo de asesores con el modelo GGAVATT fue bueno para el 50 % de ellos, pero indicaron que ha sido temporal. El 100, 74 y 62 % de los productores con IDESSP alto, medio y bajo, respectivamente, han recibido apoyos de instituciones como ECOSUR y la UNACH. Los insumos agropecuarios, son poco accesibles para el 86 % de ellos. Reciben $ 4.20 por litro de leche y el 67 % indicó que sus ingresos apenas cubren sus necesidades. Para el 93 % de ellos el nivel de intermediarismo (coyotaje) les afecta. La edad, escolaridad, ingreso extra, escasos apoyos gubernamentales y falta de conocimiento de los productores, ha limitado la adopción en los SSP, en tanto que el apoyo complementario de instituciones académicas fue importante.PALABRAS CLAVE: Adopción de tecnología, Sistemas silvopastoriles, Producción de leche, Trópico. ABSTRACTThe objective was to identify perceptions of farmers from Mezcalapa, Chiapas regarding the influence of personal and sociocultural factors, as well as support from the government and academic institutions in adoption of silvopastoral systems (SPS). A semi-structured questionnaire was applied to 23 farmers, whose answers were verified in the field. An SPSS analysis showed three conglomerates with high, medium and low levels of the SPS development index (SPSDI). Differences (P<0.05) were found regarding area covered by SPS technician and for linear meters of living fence per hectare among the three levels of SPSDI. On average, 71 % of farmers believe they know somewhat or little regarding SPS. Eighty six (86)
The objective of this study was to investigate the effects of timing and duration of lax spring grazing on tiller dynamics in perennial ryegrass swards, with and without white clover. Two periods of lax grazing-short release (SR) from 26 October to 8 December and long release (LR) from 15 September to 8 December-were compared with a conventional hard grazing-early control (EC). These treatments were applied to swards of perennial ryegrass, with and without white clover, and grazed by sheep. Tiller weight, tiller population density, tiller appearance and death, and stolon population were analysed in a factorial design with three (Experiment 1) and four (Experiment 2) replicates. Tiller weight was increased during the reproductive period, particularly in SR and LR treatments. Also, tiller appearance rate increased in all treatments from September to late January, and was particularly high late in December after grazing of the apices of the main group of reproductive tillers. Lax grazing management increased tiller appearance rate by 53% (P 0.05) in Experiment 1 and 23% (P 0.05) in Experiment 2, and tiller loss rate by 40% in Experiment 1 (P 0.05) and 23% in Experiment 2 (P 0.05). Over 6 weeks following the return to A95070 hard grazing, these effects were reflected in increased tiller population densities of 170, 147, and 115% in LR, SR, and EC treatments respectively in Experiment 1 (P 0.05), and 97, 110.5, and 36.5% in LR, SR, and EC treatments respectively in Experiment 2 (P 0.05). It is concluded that the increases in herbage production observed in summer-autumn following imposition of managements which combined lax spring grazing and hard grazing at the time of anthesis, can be attributed to increased tiller densities. The increase was most marked when the period of lax grazing was longer.
En la región de Valles Centrales de Oaxaca, localizada al sur de México, el sistema de producción familiar de aves criollas adquiere gran importancia por la generación de ingresos complementarios y la mejora de la alimentación de las familias rurales, además de la conservación de genotipos avícolas adaptados al sistema de producción y ambiente ecológico de su entorno. Sin embargo, se conoce poco sobre las características tipológicas de los grupos avícolas en explotación. El objetivo del estudio fue realizar una agrupación de gallinas criollas con base en sus diferencias fenotípicas, usando una muestra aleatoria de 171 gallinas criollas en su primer ciclo de postura en las cuales se midieron las siguientes medidas corporales: peso vivo (PV), edad, altura dorsal (AD), largo dorsal (LD), perímetro pectoral (PPE), largo de tarso (LTARSO), largo de la pierna (LPIE), largo del muslo (LMUSLO), largo del ala (LALA), ancho del ala (AALA), altura de la cresta (AC), largo de la cresta (LC), ancho del pico (AP), largo del pico (LP), largo de la barbilla (LB), ancho de la barbilla (AB), ancho de orejuela (AO), largo de orejuela (LO), ancho de cabeza (AC), largo de cabeza (LC), pluma primaria (PP). La información morfométrica se analizó estimando correlaciones de Pearson y análisis de componentes principales (CP) con variables estandarizadas. El peso vivo mostró la mayor correlación con PPE (r=0.62) y LB con AB (r=0.91), que se relacionaron con el tamaño del animal y la magnitud de la cabeza. Dos CP explicaron 63 % de la variación total; el CP1 incluyó la conformación de cabeza y extremidades (tarso y pierna), y el CP2 fue determinado por talla del ave (altura y peso). Con base en sus CP’s, las gallinas criollas adultas se clasificaron en tres tipos: muy pesadas, pesadas y ligeras, criterios que deben ser considerados en la diferenciación y selección de reproductores.
El objetivo de la investigación fue estudiar el efecto del rendimiento del pasto Brachiaria humidicola cv Chetumal a diferentes frecuencias e intensidades de pastoreo. Se evaluaron las frecuencias de corte de 21 y 28 d y las intensidades de 9-11 y 13-15 cm, que se distribuyeron de forma aleatoria en un diseño de bloques al azar con arreglo factorial 2*2 con tres repeticiones. Se observaron efecto del manejo en la acumulación de materia seca, siendo mayor la acumulación a menor frecuencia e intensidad ligera de pastoreo. La producción del forraje tuvo una distribución estacional del 66, 26 y 7% en épocas de lluvias, nortes y seca, respectivamente. La proporción de hoja en el forraje cosechado fue de 20, 30 y 86% para las épocas de nortes, seca y lluvias, respectivamente. Se registraron reducciones en la digestibilidad de la materia seca en las épocas de nortes y lluvias al aumentar el intervalo de corte. La proteína cruda con pastoreo severo fue 11, 10 y 17% mayor en las épocas de nortes, seca y lluvias que con el ligero. Se concluye que la mayor producción del forraje se obtuvo al cosechar a una intensidad ligera de 13-15 cm, cada 28 d y el mayor contenido de proteína y digestibilidad se obtuvo cuando el forraje se cosecho a intensidad severa cada 21 d.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.