Low Forage Production Research Articles

Diversity, nutrient contents and production of forage plants in an integrated cattle livestock-oil palm plantation in East Kalimantan, Indonesia

Abstract. Daru TP, Sunaryo W, Pagoray H, Suhardi, Mayulu H, Ibrahim, Safitri A. 2023. Diversity, nutrient contents and production of forage plants in an integrated cattle livestock-oil palm plantation in East Kalimantan, Indonesia. Biodiversitas 24: 1981-1989. The integration of cattle livestock rearing into oil palm plantations delivers various benefits. The livestock management can reduce the weeds and add organic nutrients to the plantations, while the understorey vegetation grow under the oil palm trees can be used as forage for the livestock. Several studies reported that the age of oil palm plantations affects forage production in integrated cattle livestock palm oil plantations. From an ecological standpoint, the diversity of plant species and the level of forage production varies based on the age of the oil palm trees. Therefore, this study aimed to determine the diversity, composition, nutrient contents, forage production and carrying capacity of understorey vegetation in oil palm plantations at different ages of 3, 7, and 10 years in Paser District, East Kalimantan Province, Indonesia. A total of 29 plant species from 13 families were found under oil palm plantations, of which 14 species (48.27%) are palatable to cattle livestock. The results showed that the diversity of plant species decreased along with the increasing age of oil palm trees, but they were able to meet the needs of livestock. In the 3, 7, and 10-year-old plantations, the diversity index (H') was 1.491, 1.634, and 2.099, with evenness index (E) of 0.538, 0.589 and 0.757; as well as the dominance index of 0.15, 0.30, and 0.18, respectively. Narrow-leaved forage plant species dominated the understorey vegetation and increased along with the age of oil palm plantations due to the ability to adapt to environmental conditions. The low forage production under the different ages of oil palm plantations caused a low carrying capacity to support livestock feed, namely 0.87, 0.56, and 0.36 Animal Unit (AU) ha-1 per year in the 3, 7, and 10-year-old plantations. Nonetheless, Crude Protein (CP) and total digestible nutrients can meet the basic life needs of livestock. The results of this study imply that oil palm plantations in Paser District can be applied as livestock rearing with different carrying capacities based on the different ages of oil palm plantations.

Plant functional trait responses to cope with drought in seven cool-season grasses

In semi-arid and arid regions, the selection of suitable grass species with high-yield production, tolerance to drought stress, and potential for recovery from drought is of special importance. Despite extensive research in cool-season grasses, inter-species differences in post-drought recovery, persistence, survival, and summer dormancy and their relationship with drought tolerance need more investigation. In the present study, 28 diverse genotypes belonged to seven cool-season grass species, including Festuca arundinacea (tall fescue), Festuca pratensis (meadow fescue), Festuca ovina (sheep fescue), Festuca rubra (red fescue), Lolium perenne (perennial ryegrass), Lolium multiflorum (Italian ryegrass) and Lolium × hybridum were evaluated during 2016–2019 under three irrigation regimes (normal, mild, and intense drought stress). Then in the fourth year (on August 2019), irrigation was withheld at all previous irrigation regimes for two months during summer, and then species were re-irrigated to study the effect of prolonged drought conditions. A wide range of genetic diversity was detected in all the measured traits among and within species in response to different irrigation levels. Recurrent drought stress decreased forage productivity, post-drought recovery, and survival in all grass species. Among the studied species, tall fescue had higher forage production, drought tolerance, survival, recovery rate, and persistence. Sheep fescue had low forage production and recovery after drought. Drought tolerance (based on stress tolerance score, STS) was highly associated with forage yield and post-drought recovery and partially with summer dormancy under both mild and intense drought stress conditions. This indicated that selection based on higher STS would lead to choosing genotypes with better recovery after prolonged drought. Superior species and preferable genotypes for forage use from species Festuca arundinacea and for turf application from species Festuca arundinacea, Lolium perenne and Lolium × hybridum were identified across different water environments for future programs.

Forage and cattle production during organic transition in dual‐purpose wheat systems

AbstractDual‐purpose wheat (Triticum aestivum L. emend. Thell.) production systems (i.e., graze and grain) are prevalent in the U.S. Southern Great Plains region, though few of them are managed organically and organic research is very limited, particularly on forage and grazing aspects of the system. Therefore, the objective of this 3‐year systems study (2018–2021) conducted near Vernon, TX, was to compare forage production, forage nutritive value, and cattle gains in transitional organic and conventional dual‐purpose wheat systems. Forage data were collected each year during the early‐season dual‐purpose grazing period until maturity. Monthly standing crop biomass, rate of forage production, and forage nutritive value did not differ during the grazing period between systems in any year. Limited early‐season precipitation resulted in slow forage growth in all years and inadequate forage production to support grazing in 2 of 3 years. In the year when grazing occurred (2018–2019), cattle performance did not differ between systems. Following the dual‐purpose grazing period, the organic system trended toward lower forage production and crude protein concentration than the conventional system, suggesting that in a “graze‐out” scenario (i.e., season‐long grazing and no grain production), the organic system might not support as much cattle production. The late‐season divergence between systems could likely be minimized or eliminated by improving N availability in the organic system. Agronomic viability of the organic system, in terms of forage production, nutritive values, and cattle gains, was supported by its overall similarity to the conventional system.

PSI-3 Balance between Productivity and Environmental Impacts of Grazed and hay Fields

Abstract Animal production has been associated with environmental impacts, but meat and dairy demand continuously increases. Grazed and hayfields have been responsible for enteric methane emissions, but also identified as great C stocks. Sustainable intensification, or balance between sustainability and productivity, is sought and we need to better understand the trade-offs to design appropriate management strategies. This study evaluated effects of grazed pastures and hayfields on carbon (C) stocks; and on soil GHG emissions (methane, CH4; nitrous oxide, N2O; and carbon dioxide, CO2), and forage dry matter and quality during four sampling periods (spring, early summer, late summer, and fall) of 2021. Forage samples were cut at stubble height, soil GHG emissions were monitored using static chamber methodology, and soil samples were collected from 0-100 cm. During the growing season, hayfields presented higher forage quality and lower forage production than grazed pastures. In addition, grazed pastures presented higher soil C stocks than hayfields. Hayfields presented lower CO2 emissions from soil in comparison to grazed pastures, suggesting slower decomposition of organic matter, which could be associated to lower C stocks. On the other hand, hayfields presented lower GHG emissions in comparison to grazed pastures, when considering CH4 and N2O emissions. Overall, a clear trade-off between the two types of fields is observed. Grazed pastures seem to be adding more C stocks over time, but also emitting more GHG emissions. Forage quality was also reduced. Hayfields had lower GHG emissions, but also lower C stocks. Forage quality was greater. In terms of long-term ecosystems' resilience and climate change mitigation, C addition from grazed pastures is more beneficial. In an eventual C market development, where C credits could be used or sold, grazing systems would be in advantage, again due to greater C stocks even if emitting slightly higher GHG emissions.

Fermentation Parameters and Quality of Sweet and Biomass Sorghum Silages With Doses of Vinasse

The cultivation of sorghum for silage production has gained more space each year because of its satisfactory nutritional characteristics, resistance to water deficit and adaptability to various types of soil. Thus, the use of sorghum silage has been an alternative for periods of low forage production, providing quality food for ruminants. In this context, the objective was to evaluate the fermentation parameters and quality of sweet and biomass sorghum silages added with doses of vinasse. The experiment was a 2 x 5 factorial completely randomized design with three replications of two sorghum species (sweet and biomass) and five doses of vinasse applied to the soil: 0; 50; 100; 150 and 200 m3 ha-1, totaling 30 experimental silos. For silage, sorghum species were harvested in the 105-day cycle, with 30.5 and 32.3 g kg-1 dry matter, for biomass and sweet sorghum, respectively. The results showed that the biomass sorghum silage showed higher dry mass production. However, the sweet sorghum silage presented a lower buffering capacity, NH3-N, and higher concentration of lactic acid. Doses of vinasse increased the content of crude protein, in vitro digestibility of dry matter and ether extract and reduced fiber fractions in both sorghum species, showing that both species can be used for silage production. Vinasse is a promising alternative to organic fertilizer, since the use of 200 m3 ha-1 positively influenced the fermentation parameters and nutritional value of the sorghum silages.

Determination of the factors affecting utilization rate of Eastern Anatolian semiarid public rangelands in Turkey

Rangelands are important natural resources for the nations with a various measurable and immeasurable outputs such as forage for farm animals, biological diversity, soil and water conservation and ecosystem functions. However, unconscious exploitation has resulted in weakening, deterioration and exhaustion of these natural resources in time. In achieving an effective, sustainable use at a minimum environmental cost without foregoing economic and social development, policy measures towards conscious utilization, conservation and restoration of these resources are of vital importance. Furthermore, user-friendly, robust policy measures require correct scientific information on the actual utilization of rangelands. The effects of various natural and human induced factors on the rangeland forage yield and its utilization rate were researched in this study. Data were collected from the rangelands of 11 villages in five districts of Erzurum province, Turkey. Descriptive statistics and mixed effect panel regression models were used in data analysis. According to the results it was concluded that 1) because of heavy grazing pressure versus low forage production, high-altitude sites, east and southwest slopes should specifically be given the priority in rangeland rehabilitation studies, 2) drought resistant species should be preferred for the overseeding practices due to the xeric nature of southerly slopes, 3) to avoid excessive exploitation and to realize balanced utilization in all rangeland sites, grazing plans should be developed and strictly followed by each village authority, and 4) Heavy grazing pressure on rangelands gets even worse in drought seasons. Therefore, rangelands should be relatively lightly utilized in such seasons not to cause herbage yield losses and other unwanted outcomes in subsequent years.

A Dual-Purpose Model for Spring-Sown Oats in Cold Regions of Northern China

Alpine regions in northern China are the traditional animal husbandry base. The lack of high-quality forage supply resulting from degradation of natural grasslands and low forage production due to short growing seasons greatly restricts development of animal husbandry in these areas. Spring oats have been widely planted in cold regions worldwide harvesting as either grains or forages because of their great adaptative ability to low temperatures and early maturation and high nutritional values. To maximize forage and grain production, we developed a dual-purpose model for spring-sown oats in the cold regions of northeastern China using two oat species, Avena nuda L. (cv. Bayou6) and Avena. sativa L. (cv. Qinghai444). Growth, forage production and quality, grain yield, and re-growth ability of the two oats were investigated in field trials and field demonstration. Maximal dry weight was found to occur at 70 days of emergence for both oats with higher forage production and crude protein (CP) in Bayou6 than Qinghai444 oat species. Neutral detergent fiber (NDF) and acid detergent fiber (ADF) of the two oats increased with time during the early vegetative growing stage, while the relative feed value showed a decrease during vegetative growing stage. The re-growth ability following cutting for the two oats reduced with increasing growth times during vegetative stage. Plant height, tiller density, CP and NDF contents of re-growing seedlings harvested at 30–40 days of emergence did not significantly differ from those of un-cutting control. The overall cumulative dry weight of biomass following cutting at 30 days of emergence was significantly higher than that of control without cutting in both oat species. Seed yield from plots cut at 30 days of emergence for both oat species was insignificantly different from that of control plots. Harvesting of spring-sown oats at 30 days of emergence enhanced forage production, but it did not influence seed yield. Results from 2-year field demonstration confirmed these conclusions. These findings highlight that this dual-purpose oat management model can have great applications in the cold regions of China.

Nutrition as a way to improve the dairy industry sustainability: a nutrigenomic approach

Abstract Due to the high incidence of diseases and high culling rate, the peripartum is a period of significant stress, and its management sets the stage for the health, future productivity and reproductive performance of the herd, hence making it the perfect target to improve the industry sustainability as a whole. Looking at grazing systems, using a nutrigenomic approach, we determined that, contrary to historic industry standards, cows should be slightly underfed (~75% of their energy requirements) in the three weeks before parturition to prime their metabolism and ensure an optimal transition. Farmer will be able to preserve pasture area in a period of low forage production, reaching the spring (calving season) with abundant and high quality pasture. While looking at confined systems we tested the supplementation efficacy of immunomodulatory nutrients. The greater feed intake and greater milk production performances (both in milk quantity, and quality), coupled with lower incidence of disease, underscore a smoother transition to lactation when cows are supplemented with rumen-protected methionine. Moreover, methionine induced greater blood neutrophil phagocytosis and oxidative burst postpartum, and optimized the response to LPS, by mitigating the hyper-response of the immune cells. Supplementation of cows undergoing a mastitic challenge with a S. cerevisiae fermentation product improved indexes of mammary gland health and pathogen resistance. Pathway analysis highlighted physiological mechanisms enhancing local immune cell trafficking, antimicrobial activity, and inflammation control in the mammary gland of supplemented animals, compared to control cows that showed signs of tissue damage and loss of epithelial integrity. Looking at calf nutrition, enhancing nutrient intake in the pre-weaning period stimulates mammary development, increasing their future productivity potential. Nutritional improvement of animal health shows great potential as a rapidly applicable strategy to improve animal welfare, allowing them to express their full genetic potential.

Impact of Climate Change on Livestock Returns and Rangeland Ecosystem Sustainability in the Southwest

Climate change will increase variability in temperature and precipitation on rangelands, impacting ecosystem services including livestock grazing. Facing uncertainty about future climate, managers must know if current practices will maintain rangeland sustainability. Herein, the future density of an invasive species, broom snakeweed, is estimated using a long-term ecological dataset and climate projections. We find that livestock stocking rates determined using a current method result in lower forage production, allowable stocking rate, and grazing value than an economically efficient stocking rate. Results indicate that using ecology and adaptive methods in management are critical to the sustainability of rangelands.

Integrating models across temporal and spatial scales to simulate landscape patterns and dynamics in mountain pasture-woodlands

Pasture-woodlands are semi-natural landscapes that result from the combined influences of climate, management, and intrinsic vegetation dynamics. These landscapes are sensitive to future changes in land use and climate, but our ability to predict the impact on ecosystem service provisioning is limited due to the disparate scales in time and space that govern their dynamics. To develop a process-based model to simulate pasture-woodland landscapes and the provisioning of ecosystem services (i.e., livestock forage, woody biomass and landscape heterogeneity). We modified a dynamic forest landscape model to simulate pasture-woodland landscapes in Switzerland. This involved including an annual herbaceous layer, selective grazing from cattle, and interactions between grazing and tree recruitment. Results were evaluated within a particular pasture, and then the model was used to simulate regional vegetation patterns and livestock suitability for a ~198,000 ha landscape in the Jura Vaudois region. The proportion of vegetation cover types at the pasture level (i.e., open, semi-open and closed forests) was well represented, but the spatial distribution of trees was only broadly similar. The entire Jura Vaudois region was simulated to be highly suitable for livestock, with only a small proportion being unsuitable due to steep slopes and high tree cover. High and low elevation pastures were equally suitable for livestock, as lower forage production at higher elevations was compensated by reduced tree cover. The modified model is valuable for assessing landscape to regional patterns in vegetation and livestock, and offers a platform to evaluate how climate and management impact ecosystem services.

Size, season and offspring sex affect milk composition and juvenile survival in wild kangaroos

AbstractThe main component of mammalian maternal care is milk production. The composition of milk has been hypothesized to determine offspring survival, and to vary with offspring sex. Few studies, however, have examined variation in milk composition of wild mammals in seasonal environments, where environmental conditions can impact the ability of mothers to provide care. We investigated individual differences in milk composition and offspring survival in wild eastern grey kangaroos (Macropus giganteus). We analyzed total protein and lipid concentrations in 103 milk samples from 91 females over 2 years. In a year of low forage production, few females that lactated were in poorer condition and produced milk of lower energy content compared to females lactating in a year of high forage production. Females nursing in late winter produced milk with more lipids compared to females at the same stage of lactation in late spring, whose milk had a higher proportion of protein. The milk of larger females contained more protein than lipid, and females in better condition allocated higher proportions of protein to sons than to daughters. Increased protein concentration in milk was correlated with offspring longevity, and this effect was stronger for sons than daughters. A seasonally modulated lactation strategy enables the adjustment of milk composition to available resources. Condition‐specific protein allocation in favor of sons for mothers of higher caring ability suggests adaptive sex‐biased maternal care in this highly sexually dimorphic mammal.

Effects of Site Characteristics, Pinyon-Juniper Management, and Precipitation on Habitat Quality for Mule Deer in New Mexico

Wildlife enterprises are increasingly important to ranch income in the western United States. Habitat management practices that facilitate wildlife are needed for optimal management of multiple-use ranches, particularly for economically important species, such as mule deer (Odocoileus hemionus), that are declining throughout much of their range. We tested the effects of vegetation cover type, site characteristics, pinyon-juniper management treatments, and precipitation on body condition and size of spring-summer-autumn (SSA) home ranges of mule deer to assess habitat quality on the Corona Range and Livestock Research Center (CRLRC), a multiple-use research ranch in eastcentral New Mexico. Accrual of lean tissue and body fat reserves in does was positively associated with use of mechanically cleared juniper, pinyon-juniper woodland, and savannah and increased annual and spring (April to June) precipitation. Size of SSA home ranges of does was negatively associated with use of pinyon-juniper woodland and savannah and mechanically cleared pinyon-juniper stands, indicating that habitat quality was positively associated with use of these types. Conversely, size of SSA home ranges was positively related to use of short grass prairie (does), proportion of short grass prairie in SSA ranges (bucks), and areas of low forage production classes (does, bucks). Overall, habitat quality for deer on CRLRC was most positively associated with a mix of thinned and unmanaged pinyon-juniper habitat. Conversely, habitat quality was negatively associated with use of short grass prairie, which is the most common (77%) vegetation cover type on CRLRC. Management for deer habitat should focus on increasing forage, particularly shrub communities, by opening pinyon-juniper communities while maintaining sufficient area in unmanaged woodland for cover. Deer responses are likely to be greater if management focuses on sites of higher forage production potential within 200 m of unmanaged pinyon- juniper stands.

<b>Silage quality of <i>Urochloa brizantha</i> cultivars with levels of campo grande Stylosanthes

The seasonality of forage production represents a limiting factor in the production of ruminants. The use of silages has been a solution for periods of low forage production, providing high quality food. This study was conducted to evaluate the fermentative characteristics and the chemical composition of silage of Urochloa brizantha cultivars with different levels of Campo Grande Stylosanthes. It was used a complete randomized block design with three replications in a 2 x 4 factorial design, being two cultivars of Urochloa brizantha (BRS Piata palisadegrass and BRS Paiaguas palisadegrass) and four levels of Campo Grande Stylosanthes (0, 10, 20 and 30%). Silages of Urochloa brizantha with Campo Grande Stylosanthes exhibit satisfactory quality, on the basis of the characteristics evaluated, with no significant difference between cultivars. The mixed silage of Campo Grande Stylosanthes with grasses at 30% has proven to be an interesting option, thus promoting adequate fermentation and maintaining the nutritional quality of silage.

Production and nutritional characteristics of sunflowers and paiaguas palisadegrass under different forage systems in the off season

The high efficiency of sunflowers in extracting water from the soil under water stress conditions is a factor that promotes sunflower cultivation in the offseason. Therefore, sunflowers have been intercropped with grasses of the Brachiaria genus in crop-livestock integration systems. However, little is known of sowing methods for intercropping; thus, the present study aimed to assess sunflower agronomic traits and the production and nutritional characteristics of Paiaguas palisadegrass under different forage systems in the offseason in the midwest region of Brazil. The experiment was conducted at the Federal Institute of Goias (Instituto Federal Goiano), Rio Verde Campus in a randomized block experimental design with four replicates. The treatments consisted of the following forage systems: sunflower monocropped; Paiaguas palisadegrass monocropped; sunflower rows intercropped with Paiaguas palisadegrass; sunflower inter-row intercropped with Paiaguas palisadegrass; and sunflower oversown and intercropped with Paiaguas palisadegrass. The results show that the sunflower rows intercropped with Paiaguas palisadegrass negatively affect the agronomic traits of sunflower; thus, inter-row sowing and oversowing are recommended. Sowing Paiaguas palisadegrass with oversown sunflower for forage production is hampered by intercropping and shows low forage production. In turn, the intercropped sowing method had no effect on the nutritional characteristics of the produced forage. Intercropping sunflowers with Paiaguas palisadegrass in the offseason has the potential to provide a promising cropping method for the production of achenes and after harvest enables the availability of forage with good nutritional value for use in the offseason in the midwest region of Brazil.

Rain Use Efficiency, Primary Production and Rainfall Relationships in Desert Rangelands of Tunisia

AbstractDesert rangelands are characterised by low and highly variable rainfall regime, low forage production and high heterogeneity in the distribution of natural resources. This study was carried out in the desert rangelands of Tunisia to evaluate the response of different rangelands to annual rainfall in terms of aboveground net primary production (ANPP) and rain use efficiency over a 10‐year period (2003–2012). In general, ANPP values were relatively low (123 kg DM ha−1 y−1) but would tend to increase with increasing annual rainfall for all rangeland types. The highest value of ANPP was observed from Stipagrostis pungens and Hammada shmittiana communities (sandy‐soil) during the wet year 2011. In contrast, rain use efficiency tends to decline with the highest annual rainfall and varies among rangeland types and with an average of 1·9 kg DM ha−1 mm−1 y−1. Rain use efficiency tended to be higher during dry years and lower during wet years and tended to be higher on S. pungens and H. shmittiana (sandy‐soils) and lower on Helianthemum kahiricum (loamy soils). Therefore, understanding how rainfall affects productivity in rangelands is critical for predicting the impact of land degradation on the functioning of these ecosystems. It can be used to explain production decline associated with desertification as well as to assess rangeland conditions. Copyright © 2015 John Wiley & Sons, Ltd.

Climate change scenarios of herbaceous production along an aridity gradient: vulnerability increases with aridity.

Climate change is expected to reduce annual precipitation by 20% and increase its standard deviation by 20% in the eastern Mediterranean. We have examined how these changes may affect herbaceous aboveground net primary production (ANPP) and its inter-annual coefficient of variation (CV) in natural rangelands along a desert-Mediterranean precipitation gradient, at five sites representing arid, semi-arid, and Mediterranean-type ecosystems, respectively, all showing positive linear relationships between herbaceous ANPP and annual precipitation. Scenarios of reduced annual precipitation and increased inter-annual precipitation variability were defined by manipulating mean annual precipitation (MAP) and its standard deviation. We simulated precipitation and calculated ANPP using current ANPP-precipitation relationships. Our model predicts that reduced precipitation will strongly reduce ANPP in arid and semi-arid sites. Moreover, the effect of reduced precipitation on the CV of ANPP along the entire gradient may be modified by changes in inter-annual variability in MAP. Reduced precipitation combined with increased precipitation variability was the scenario most relevant to the wet end of the gradient, due to the increased likelihood for both dry and rainy years. In contrast, the scenario most relevant to the arid end of the gradient combined reduced precipitation with decreased precipitation variability, due to the strong effect on mean ANPP. All scenarios increased variability of ANPP along the entire gradient. However, the higher sensitivity of vegetation at arid and semi-arid sites (i.e., lower forage production) to future changes in the precipitation regime emphasizes the need to adapt grazing management in these ecosystems to secure their long-term viability as sustainable rangelands.

Análise espacial de atributos do solo e cobertura vegetal em diferentes condições de pastagem

As áreas destinadas à pecuária têm-se expandido sobre áreas de vegetação nativa promovendo transformações na qualidade do solo. O objetivo foi avaliar os atributos de um Neossolo Quartzarênico sob diferentes coberturas vegetais para saber se a degradação do pasto representa a degradação do solo. As áreas avaliadas foram: floresta nativa; capoeira; pastagem sem controle de lotação animal; pastagem em pousio; pastagem com invasoras; pastagem degradada com solo descoberto e invasoras, pastagem degradada com invasoras e espécies arbóreas e pastagem com baixa produção de forragem. Todas as pastagens eram formadas pela gramínea Brachiaria brizantha cv. Marandu. Realizaram-se 128 amostras de solo nas profundidades de 0-5 e 5-10 cm, dentro de cada área de manejo considerada como parcela experimental e a cobertura do solo foi quantificada. Foram mensuradas propriedades químicas e físicas do solo. Os dados foram submetidos a estudo geoestatístico. Foram constatados aumento na resistência mecânica à penetração e diminuição nos teores de matéria orgânica nas áreas mais degradadas. Pasto degradado não representa necessariamente solo degradado enquanto solo degradado está relacionado a pastagem degrada.

Producción de forraje y respuesta de cabras en crecimiento en arreglos silvopastoriles basados en Guazuma ulmifolia, Leucaena leucocephala y Crescentia cujete

El monocultivo de gramíneas, además de no ajustarse a los hábitos alimenticios naturales de los caprinos, presenta una deficiente producción de forraje durante la época de sequía, con repercusiones negativas sobre la productividad animal. Se determinaron las ventajas productivas de los arreglos silvopastoriles para sistemas de producción caprinos. Se utilizó un diseño experimental completamente al azar, con medidas repetidas en el tiempo. Se evaluaron seis tratamientos: monocultivo de pasto kikuyina (Bothriochloa pertusa) y monocultivo de pasto guinea (Panicum maximum cv. Tanzania) como testigos; y cuatro arreglos basados en guácimo (Guazuma ulmifolia); totumo (Crescentia cujete); leucaena (Leucaena leucocephala); y mixto (guácimo, totumo, leucaena). Las informaciones obtenidas se sometieron a análisis de varianza. Los resultados revelaron mayor producción de forraje en los arreglos silvopastoriles en relación con el monocultivo de Bothriochloa pertusa. El mayor (p < 0,05) crecimiento en altura, de 9 a 14 meses de edad, correspondió a leucaena. Los arreglos asociados presentaron ventajas en producción de forraje comparado con B. pertusa. Se destaca la más alta producción de materia seca de pasto guinea. La ganancia de peso de las cabras en crecimiento fue baja; sin embargo, se observó una respuesta diferenciada por los tratamientos. Los arreglos silvopastoriles presentaron las mayores (p < 0,05) ganancias de peso (22,5 a 33,6 g/animal al día) en relación con el monocultivo pasto guinea (13,2 g/animal al día). Las cabras en crecimiento presentaron mayores porcentajes de celo en los tratamientos mixto (66,7%), y los basados en guácimo (66,7%) y en leucaena (55,6%).

Cultivares de trigo duplo propósito submetidos ao manejo nitrogenado e a regimes de corte

Avaliaram-se a produção e a qualidade da forragem em cultivares de trigo duplo propósito submetidos a doses de nitrogênio e a regimes de corte. O delineamento experimental foi o de blocos ao acaso com três repetições. Os tratamentos constituíram-se de quatro cultivares de trigo duplo propósito - BRS Figueira, BRS Umbu, BRS Guatambu e BRS Tarumã -, cinco doses de nitrogênio - 0, 45, 90, 135 e 180kg ha-1 - e três manejos de corte - sem corte, um e dois cortes. As variáveis avaliadas foram: produção de forragem, relação de folhas, proteína bruta, digestibilidade in vitro da matéria orgânica e nutrientes digestíveis totais. A adubação nitrogenada apresentou comportamento linear crescente sobre a produção de massa e proteína da forragem e não houve efeito sobre as demais variáveis. A produção de forragem aumentou no segundo corte e sua qualidade decresceu. Os resultados quantitativos e qualitativos da forragem foram distintos entre os cultivares. Os cultivares de trigo duplo propósito de ciclo mais longo apresentaram maior qualidade forrageira e menor produção de forragem.

Allelopathic effects of Thymus kotschyanus on seed germination and initial growth of Bromus tomentellus and Trifolium repens

The allelopathic influence of aqueous extracts of Thymus kotschyanus on Bromus tomentellus and Trifolium repens germination (%), germination speed, and seedling growth (length, fresh and dry weight) was examined. It was noted that aqueous extracts had a considerable inhibitory effect on target plant germination, and the effect at 50%, 75%, and 100% concentration was found to be significantly higher than that at lower concentrations (5% and 25%) and control treatment (distilled water). Seedling length in addition to fresh and dry weights was also reduced significantly over control. The inhibitory effect was increased as the extract concentration was increased. B. tomentellus showed a higher sensitivity against T. kotschyanus in allelopathic effects compared to T. repens, which indicates that B. tomentellus planted in rangelands with leaf litter of T. kotschyanus will be adversely affected in terms of its germination, growth, and ultimately low forage production.