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Land degradation is a global problem leading to a diminished production capacity of the rangelands. The consequence is reduced potential to provide ecosystem services and increased vulnerability to the inhabitants. Biological soil water conservation measures can reverse the trend. Different communities prefer different grass species for rehabilitation as communities vary in location, needs, priorities, preferences and the type of livestock reared. This study, therefore, sought to identify the suitable grass species for soil erosion and rehabilitation from the community in Keekonyoie ward In Narok county, Kenya. Data collection was through individual interviews, focus groups, key informant interviews and field observations. Results showed that level, indicators, causes and impacts are known to the community. Cynodon plectostachyus (76%), Chloris gayana (73%), Pennisetum clandestinum (69%), Cymbopogon citratus (46%) and Themeda triandra (42%) were most preferred for rehabilitation and soil erosion control. The primary reason for the grasses choice was a yearlong provision of livestock feed. Needs and livelihood priorities significantly influence decision-making among the Maa-speaking community in Keekonyoie ward. We recommend consideration of community needs, priorities and preferences in the selection of grass species for rehabilitation to increase the adoption measures that can reverse land degradation Key words: Indigenous knowledge, community perceptions, range grass species, rehabilitation, land degradation, Narok.

The local ecological knowledge (LEK) and perceptions of grasses were investigated in six semi-arid communal areas in the central Eastern Cape province, South Africa, and compared with field studies and scientific knowledge. Of the total of 21 grasses identified in the field survey, communal farmers had vernacular names only for 11 species. Respondents rated Digitaria eriantha and Pennisetum clandestinum to have the highest (p < 0.05) grazing value. Respondents’ ratings of Eragrostis obtusa and Sporobolus africanus as having similar (moderate) grazing values to Themeda triandra is against the established knowledge. Respondents’ ratings of T. triandra and S. africanus as having higher (p = 0.01) ecological value than the other grasses concur with the scientific knowledge, whereas their nomination of E. obtusa and D. eriantha as providing less ecological benefits than Aristida conjesta disagrees with some ecologists. The study hinted at the complementarity and discrepancies between LEK and scientific knowledge that need ratification. The respondents’ lack of detailed knowledge is suggestive of a gradual eroding of LEK among the local communities that will adversely impact the local people’s ability to implement sustainable rangeland utilisation practice. The current study also recognised farmers’ familiarity as well as training needs that would expound their knowledge and management of grasses.Keywords: communal grazing, ecological value, forage production, grazing value, semi-arid

Pasture meters are typically calibrated to estimate total pasture mass (TPM). Recent studies have shown that animal productivity was driven by the level of utilisation of the top leafy stratum (TLS) rather than the TPM. A study of kikuyu (Pennisetum clandestinum) pasture conducted on two farms located in southeast Queensland, Australia assessed whether pasture mass of the TLS, bottom stemmy stratum (BSS) and TPM can be more accurately estimated by using not only pasture surface height but also pasture density derived from height data captured by a laser sensor. The results indicated that there was a notable improvement of the pasture mass estimates when density was included in the calibration equations. The study also compared the accuracy of the pasture mass estimates between the laser sensor and mechanical pasture meters (rising plate meter and ruler). The results indicated that all devices provided reasonable estimates of pasture mass for TLS, BSS and total (R2 ≥ 0.75). However, pasture mass was estimated with a slightly higher level of accuracy when using the laser sensor in comparison with the other pasture meters, particularly for the top leafy stratum (R2 = 0.81 vs R2 ≤ 0.77).

The Brazilian cattle herd (>200 million) contributes, via excreta, 41% of the national emission of nitrous oxide (N2O), but little country-specific information exists on related emission factors and mitigation options. The aims of this study were: (i) to determine the N2O emission factors (EF) for dairy cattle urine and dung in a subtropical pasture and compare them with the 2% EF adopted by the IPCC; (ii) to evaluate the efficacy of the nitrification inhibitor dicyandiamide (DCD) to reduce those N2O emissions; and (iii) to determine if the best mode of DCD application is dissolved into or sprayed on urine and dung. An experiment was conducted in a kikuyu grass (Pennisetum clandestinum) pasture over a haplic Cambisol, in southern Brazil. Fresh urine and dung from Friesian dairy cows were applied with or without application of DCD; DCD was dissolved into the excreta before its application onto the soil, or was sprayed on the excreta patch. Treatments were applied four times, once per each season of 2014 (in different spots, same area). After excreta application, N2O fluxes were monitored in 10 air sampling sessions over 63–68 days, by using closed static chambers. Urine and dung were important sources of N2O, with an average EF of 0.34% for urine and 0.11% for dung; this urges the investigation of related mitigation strategies for Brazilian cattle systems. Yet, those emission factors were not as high as the IPCC default value of 2%, which suggests that this default value may need to be revised for the subtropical region. Additionally, this revision should consider the disaggregation of the EF for urine and dung. As a mitigation strategy, the use of DCD had a potential to curb N2O emission from urine patches, particularly in the cooler seasons of autumn and winter, when it reduced emissions by 60–82% after being dissolved in urine. DCD sprayed on excreta patches significantly reduced emissions in autumn only (by 47%) and thus was less efficient than when dissolved in urine. With respect to dung, there was no clear evidence that N2O emission from that excreta is mitigated by DCD, either dissolved into the dung mass or sprayed over the dung pat. ––

Grain-based concentrate (GBC) supplement is of high cost to dairy farmers as a feed source as opposed to grazed pasture. Milk production response to GBC is affected by the composition and nutritive value of the remainder of the diet, animal factors, and interactions between forage type and level of GBC. In grazing systems, dairy cattle encounter contrasting pasture states, primarily because the social structure of the herd affects the timing of when each animal accesses a paddock after milking as a result of a relatively consistent cow milking order. However, the effect of feed management, namely pasture state and GBC allocation, on dairy cattle production and behavior is unknown. We examined the effect of varying GBC allocation for dairy cattle grazing differing states of kikuyu grass (Pennisetum clandestinum, a tropical pasture species; experiment 1) and annual ryegrass (Lolium multiflorum L., a temperate pasture species; experiment 2) on dry matter intake, milk production and composition, and grazing behavior. For each experiment, 90 lactating dairy cattle were randomly allocated to 2 consistent (fresh-fresh and depleted-depleted) and 2 inconsistent (fresh-depleted and depleted-fresh pasture state treatments (defined as sequences of pasture state allocation for the morning and afternoon grazing events) and 3 GBC treatments [2.7, 5.4, and 8.1 kg of dry matter (DM)/cow per day], giving 12 treatment combinations for each experiment. The duration of each experiment was 14 d, with the first 7 d used as adaptation to treatment. In each experiment, 3 cattle were selected from each of the 12 pasture type × GBC treatment groups within the experimental herd to determine herbage intake and total DM digestibility using the n-alkanes method (n = 36). There was no interaction between kikuyu grass or ryegrass pasture state and GBC level for intake, digestibility, or milk yield or components. Dairy cattle offered fresh-fresh and depleted-fresh ryegrass produced 9% more milk yield, in line with greater pasture intakes, compared with fresh-depleted and depleted-depleted pasture states. Dairy cattle offered fresh-fresh kikuyu grass had 8% more milk yield and 14% more milk protein yield than other pastures states, but there was no effect of pasture state on milk composition. Milk yield increased with GBC level for both pasture species (∼0.7-0.8 kg of milk/kg of DM GBC) as GBC level increased from 2.5 to 5.4 kg of DM/cow per day. There was a poor response (0.3 kg of milk/kg of DM GBC), and no response, when GBC levels increased from 5.4 to 8.1 kg of DM/cow per day for kikuyu grass and ryegrass, respectively, in line with pasture DMD. Time spent grazing, lying, and ruminating were not associated with kikuyu grass pasture state, GBC, or their interaction. Despite this, there was a linear increase in grazing time in the afternoon coinciding with a linear decrease in lying and rumination time for both kikuyu grass and ryegrass pasture. Together these findings reveal the effect of pasture state and GBC allocation on dairy cattle production and behavior. Tailoring GBC allocation to the state of pasture accessed by cattle appears unwarranted, but there is an opportunity to alter the timing of pasture access to increase herd-level milk production efficiency.

Enteric CH4 emissions from ruminant livestock represent a loss of dietary energy and contribute to greenhouse gas emissions, actually, that is depending on feeding level and diet composition. We calculated emission factors of methane depending to enteric fermentation of Holstein cattle in Andean zone of Colombia, based on methodology IPCC Tier 2. This study involved animal performance, management practices for improved livestock productivity, higher digestibility of pasture and forage from silvopastoral system of the association Pennisetum clandestinum/Trifolium repens on paddocks bounded by live fences of Acacia decurrens. For that, some model parameters and Tier-2 model equations were applied: body weight, mature weight, daily gain, weight loss, milk production, milk fat content, pregnancy rates and quality of feed to calculate gross energy GE. All these variations were used to investigate the effects on predicted CH4, emission in terms of the changes in the CH4 emission factor (MEF) in kg of CH4 per head dairy cattle−1 year−1. CH4 conversion factor (MCF) as a percentage of gross energy intake with feed, resulting in emission factor of 52 kg CH4 head−1 year−1 in SPS, 28 and 45% lower than in improved pasture of Lolium multiflorum and degraded pasture of Pennisetum clandestinum in rotation with potatoes, resulting in emission factors of 72 and 93 kg CH4 head−1 year−1 respectively. These emission factors were compared with the emission factors of Tier-1 and Tier-2 methodology used value Ym default of IPCC from national inventories. Through this research these emission factors can be applied for regional and national inventories in Andean areas of Colombia with these features.

El presente estudio se realizó en un Andisol clasificado como Vitric haplustands, ubicado en el Corregimiento de Obonuco, Municipio de Pasto (Colombia). Se evaluaron algunas características químicas, en siete tipos de uso y manejo del suelo: T1: monocultivo de papa (Solanum tubersum L.), T2: pradera (Pennisetum clandestinum Hochst. ex Chiov), T3: barrera multiestrato, T4: sistema acacia - aliso, T5: banco de proteína, T6: bosque plantado (Eucaliptus globulus Labill) y T7: bosque nativo. El efecto de los tipos de uso y manejo, sobre las propiedades químicas del suelo, se evaluaron a través de pH, %MO, %CO, N total, P, CIC, Ca, Mg, K, Al, Fe, Mn Cu, Zn, B y S. Los resultados fueron sometidos a Análisis de Varianza, Prueba de Comparaciones de Medias (LSD), Diferencia Mínima Significativa (DMS) y correlaciones de Persson. Los valores mostraron diferencias significativas (P

The diversity of the riparian vegetation of five high Andean lagoons of the Junin region was evaluated between March and December of 2017. The sampling of the riparian vegetation was carried out by means of the transect method. The unidentified species were collected for later identification in the herbarium. The diversity was determined by floristic composition, abundance and frequency, and by species richness indices of Simpson and Shannon-Wiener. In the Pomacocha Lagoon, the floristic composition was represented by 43 species, distributed in 15 families, with the most abundant species being Aciachne pulvinata, Azorella crenata and Geranium sessiliflorum and the most frequent Aciachne pulvinata. In the Laguna Tragadero, the floristic composition was represented by 17 species, distributed in 10 families, with the most abundant species being Pennisetum clandestinum and Eleocharis sp and the most frequent Polypogon interruptus. In the Cucancocha Lagoon, the floristic composition was represented by 19 species, distributed in 7 families, with the most abundant species being Calamagrostis sp and Wernberia humbellata and the one of most frequent Carex ecuadorica. In the Incacocha Lagoon, the floristic composition was represented by 22 species, distributed in 11 families, with the most abundant and frequent species being Alchemilla pinnata. In the Ñahuinpuquio Lagoon, the floristic composition was represented by 20 species, distributed in 9 families, with the most abundant species being Pennisetum clandestinum and the most frequent species Pennisetum clandestinum, Juncus arcticus and Muhlenbergia andina. The results obtained contribute data on the diversity of riparian vegetation of high Andean wetlands in the Junin region, Peru. Resumo Avaliou-se a diversidade da vegetação ripária de cinco lagos altos andinos da região de Junin entre março e dezembro de 2017. A amostragem da vegetação ripária foi realizada por meio do método de transectos. As espécies não identificadas foram coletadas para posterior identificação no herbário. A diversidade foi determinada pela composição florística, abundância e frequência e pelos índices de riqueza de espécies, Simpson e Shannon-Wiener. Na lagoa Pomacocha a composição florística foi representada por 43 espécies, distribuídas em 15 famílias, as espécies mais abundantes foram Aciachne pulvinata, Azorella crenata e Geranium sessiliflorum e a mais frequente Aciachne pulvinata. Na lagoa Tragadero a composição florística foi representada por 17 espécies, distribuídas em 10 famílias, as espécies mais abundantes foram Pennisetum clandestinum e Eleocharis sp e a mais frequente Polypogon interruptus. Na lagoa Cucancocha a composição florística foi representada por 19 espécies, distribuídos em 7 famílias, as espécies mais abundantes foram Calamagrostis sp e Wernberia humbellata e a mais frequente Carex ecuadorica. Na lagoa Incacocha a composição florística foi representada por 22 espécies, distribuídas em 11 famílias, sendo a espécie mais abundante e freqüente Alchemilla pinnata. Na lagoa Ñahuinpuquio a composição florística foi representada por 20 espécies em 9 famílias, sendo a espécie mais abundante Pennisetum clandestinum e as espécies mais freqüentes Pennisetum clandestinum, Juncus articus e Muhlenbergia andina. Os resultados obtidos contribuem com dados sobre a diversidade da vegetação ripária das áreas úmidas andinas da região de Junin, no Peru.

Soil quality of tillage systems receives much attention worldwide, although few studies attempt to link soil quality to yield. Partial least-squares regression analysis is a suitable method to construct predictive models around plural, highly collinear factors, such as soil quality and its effects on yield. This study aimed at identifying the soil quality properties which best model pasture herbage yield by relating soil quality indicators with variations in yield as a result of soil disturbance caused by tillage. The study was conducted on kikuyu (Pennisetum clandestinum) over-sown with annual ryegrass (Lolium multiflorum) using different tillage methods. Tillage methods involved over-sowing kikuyu with ryegrass using a minimum-tillage seed drill, eradication of kikuyu with herbicide and ryegrass sown with a minimum-tillage planter, shallow and deep disturbance, and a control. Most changes in soil quality indicators as a result of soil tillage were observed shortly after tillage and occurred mostly at the 0–100 mm soil layer. Few of these effects were still visible 420 d after tillage. Microbiological indicators changed most in response to the treatments, but unlike the chemical and physical indicators, microbiological indicators have no causal link to pasture production. The contribution of individual soil quality indicators to variance in pasture productivity could not be isolated and should thus be seen as complex processes which affect yield. Although mechanisms of how some soil quality indicators affect yield is clear, more research is required to determine mechanisms of how a combination of multiple soil quality indicators affects yield.

This research focused on the greenhouse gas (GHG) emissions and potential sinks associated with conventional and sustainable fruit production systems in the Highlands region of Pasto, Narino, Colombia. Based on the IPCC (2006) methodologies, the annual emission balance for a 6-year production cycle included agricultural sources and gasoline consumption related to the main agricultural activities and the potential for soil C accumulation and biomass C fixation in all of the studied systems. The multivariate analysis showed that positive GHG balance emissions would be achieved in all sustainable fruit production systems, as compared to conventional fruit production systems with greater impact on (SS1): Rubus glaucus Benth. Associated with Acacia decurrens trees and live coverage of kikuyu Pennisetum clandestinum grass. According to the results of this study, (SS1) showed the beneficial total GHG balance emission accounting for -21,079 kg of atmospheric CO 2 eq ha -1 yr -1 divided into -4,587 kg CO 2 eq ha -1 yr -1 and -17,102 kg CO 2 eq ha -1 yr -1 due an annual soil and biomass C sequestration potential that could help offset its emissions (610 kg CO 2 eq ha -1 yr -1 ).

El presente trabajo estuvo orientado a evaluar la precisión del algoritmo de análisis de imágenes Red, Green, Blue (RGB), incluido en el software TaurusWebs ®, que permite calcular el porcentaje de proteína cruda de la materia seca (%PC) de las gramíneas a partir de imágenes de las praderas tomadas por un dron acoplado con cámaras RGB. Se compararon las mediciones del %PC calculadas por el algoritmo frente a un referente, Near Infrared Reflectance Spectroscopy (NIRS), del laboratorio de Corpoica (Agrosavia), calibrado para gramíneas. Se tomaron 42 muestras para NIRS, 18 de gramíneas de trópico alto en Cundinamarca: kikuyo, Pennisetum clandestinum; falsa poa, Holcus lanatus; pasto brasilero, Phalaris arundinacea y 24 de trópico bajo en Tolima, Colombia: pangola, Digitaria decumbens; pará, Brachiaria mutica; bermuda, Cynodon dactylon y colosuana, Bothriochloa pertusa. Los resultados del NIRS se compararon contra las evaluaciones hechas con el algoritmo de las imágenes de las gramíneas provenientes del mismo potrero donde se tomaron las muestras. Los resultados fueron comparados usando las pruebas no paramétricas de correlación de Kendall, rho=0.83 y de Kruskal Wallis. No se encontraron diferencias entre el resultado del %PC de las gramíneas medida por NIRS vs el %PC medida por el algoritmo de análisis de imágenes RGB. En conclusión, la información generada con el algoritmo se puede utilizar para trabajos de análisis del %PC en gramíneas.

The turnover of soil organic carbon (SOC) under different land uses plays an important role in terrestrial carbon (C) cycling. However, the effects of warming on C decomposition dynamics have not been resolved due to seemingly inconsistent results among different experiments. Hence, the objective of this work was to assess soil aggregate-associated C and temperature sensitivity of SOC decomposition within bulk soils and aggregates under two contrasting land management systems in subtropical southern Queensland.We examined the temperature sensitivity of SOC decomposition (Q) and activation energy required for soil C mineralization (Ea) from bulk soils (

Resumen Los sistemas de producción de rumiantes en Colombia están soportados en el uso de forrajes, principalmente el kikuyo en el trópico alto (Cenchrus clandestinus, previamente Pennisetum clandestinum). El objetivo de este trabajo fue recopilar la información relacionada con el kikuyo e identificar nuevos campos de investigación que permitan promover un manejo eficiente y sostenible de los sistemas de producción bovino soportados en praderas de kikuyo. Los trabajos sugieren que el kikuyo presenta gran resiliencia ante condiciones ambientales adversas, lo que lo perfilan como una especie de interés ante los nuevos escenarios de variabilidad climática. Además, la literatura reporta estrategias de manejo que promueven el aumento en la producción animal, el mejoramiento en la calidad final del producto y la disminución en el impacto sobre el ambiente. Sin embargo, el kikuyo presenta limitaciones en la respuesta agronómica y composicional que hace necesario desarrollar trabajos de investigación que permitan profundizar en el conocimiento de las relaciones entre las condiciones edafoclimáticas y de manejo que promueva el desarrollo de modelos de optimización de los sistemas de producción. Finalmente, se debe promover programas que permitan conocer las características fenotípicas y genotípicas del kikuyo y definir programas de mejoramiento genético que potencialicen la expresión de esta gramínea en condiciones ambientales específicas. Abstract Colombian ruminants’ systems are supported in grasslands, mainly kikuyu in highlands (Cenchrus clandestinus, previously Pennisetum clandestinum). The objective of this work was to compile information related to kikuyu and identify new research areas to promote an efficient and sustainable ruminants’ systems supported in kikuyu. The literature suggests that kikuyu presents great resilience to adverse environmental conditions, especially in new scenarios of climatic variability. In addition, literature reports management strategies to improve animal production, product quality and reduce environmental impact. However, kikuyu presents limitations of agronomic and compositional response, that makes necessary to develop research works that allow increase knowledge between edafo-climatic relations and management conditions to development optimization models for kikuyu production systems. Finally, it is necessary to promote phenotype and genotype studies and define genetic improvement programs to enhance grass expression under specific environmental conditions. Resumo Os sistemas de produção de ruminantes na Colômbia são baseados na utilização de forragens, principalmente kikuyo nos trópicos superiores (Cenchrus clandestinus, anteriormente Pennisetum clandestinum). O objetivo deste trabalho foi coletar informações relacionadas à kikuyo e identificar novos campos de pesquisa que promovam o manejo eficiente e sustentável de sistemas de produção bovino alimentados com pastagens de kikuyo. Estudos sugerem que o kikuyo tem grande resiliência a condições ambientais adversas, despertando grande interesse tendo em vista os novos cenários de variabilidade climática. Além disso, a literatura relata estratégias de manejo que promovem o aumento da produção animal, a melhoria na qualidade final do produto e a diminuição do impacto no meio ambiente. Entretanto, o kikuyo apresenta limitações no que diz respeito à resposta agronômica e composição necessárias para desenvolver pesquisas que aprofundem a compreensão das relações entre as condições e manejo do solo e o clima que promovam o desenvolvimento de sistemas de modelos de otimização da produção. Finalmente, devem ser desenvolvidos programas que permitam conhecer as características fenotípicas e genotípicas desta forragem, além de definir programas de melhoramento genético que potencializem a expressão dessa gramínea em condições ambientais específicas.

This study was conducted in the municipality of Guachucal, Department of Narino, existing farming systems were characterized, analyzed the function and structure of the tree component and relate tree cover with the intensification of production systems. Stratified farms according to its area, where three strata were obtained: I (0.5 - 3 has), II (3.1 - 6 has) and III (> 6 has). Then applied a stratified sampling using the formula of Ballesteros, with a total of 200 farms, which were classified according to each stratum. To obtain the different diagnoses was a semi-structured survey, which was analyzed using a statistical analysis of major components, multiple correspondence (ACM) and Pearson correlations. The predominantly traditional production system is the perennial ligneous forestry - potato-pasture-bovine milk, characterized by being made with tree species such as: pandala (Clethra sp.), capuli (Prunus cerotina), alder (Alnus acuminata), acacia (Acacia decurrens), eucalyptus (Eucalyptus globulus), Cypress (Cupressus sp.). Regarding grasses predominated the mixture of Pennisetum clandestinum, Holcus lanatus, Lolium multiflorum, and Trifolium repens L; and dominates the race of Holstein cattle. He was also obtained that 95% of farms are paddocks, 100% present mix of native and improved pastures, where the 70.5% manages a production system no stanchion, t 19% and 10.5% stanchion. In the hedgerows, the most representative species of the farms were acacia (Acacia melanoxylom) pine (Pinus patula), used mainly for firewood, poles and wood. The relationship of tree cover with the intensification of production systems is given in a positive way by the area of the estate, area in pasture, cows in production, calf nursing, total production of milk per day, and costs of livestock. Key words: Forestry system, multivariate analysis, hoists cover

Summary Distributions of invasive alien species (IAS) are well documented all over the world, and roads are considered one of the main means by which IAS spread. Bolivia is one of a few countries for which there are no such studies. For this reason, we determined the number of exotic plant species in the vicinity of roads near the city of La Paz, Bolivia. We distinguish two types of roads, paved and gravel roads, and in their vicinity, we studied the floristic composition in three regions, differing mainly in altitude: high Andes, puna grassland and dry valley. We found three exotic species in the vicinity of roads in the high Andes, five in puna grassland and 10 in the dry valley. We found 13 exotic species along gravel roads and nine along paved roads, whilst there was a trend for such species to be more abundant close to the roads than further away. Pennisetum clandestinum was the most frequently recorded exotic species in all regions and associated with both types of roads. The results indicate that exotic species are quite frequent along roads in Bolivia and present a potential threat as invasive species. Therefore, it may be necessary to take measures to prevent IAS from spreading further.

Kikuyu (Pennisetum clandestinum) is a highly productive pasture species that supports high stocking rates and milk production per hectare, but production per cow is low due to low nutritive value. The aim of this study was to determine the grazing capacity, milk production and milk composition of dairy cows grazing irrigated kikuyu over-sown with Italian (Lolium multiflorum var. italicum), Westerwolds (L. multiflorum var. westerwoldicum) or perennial ryegrass (L. perenne) during autumn. The grazing capacity of the kikuyu–ryegrass systems was lower during winter and autumn than during spring and summer, with the seasonal grazing capacity of the perennial ryegrass treatment more evenly distributed than that of the Italian and Westerwolds ryegrass treatments. The perennial ryegrass treatment had a lower butterfat and milk production per lactation than the Italian and Westerwolds ryegrass treatments, but had the highest milk solids and fat corrected milk production per hectare. The latter was a result of the higher annual grazing capacity achieved by the perennial ryegrass treatment. It was concluded that because kikuyu over-sown with perennial ryegrass supported a higher number of animals and had a more evenly distributed fodder-flow, it achieved higher animal production per hectare than kikuyu over-sown with annual ryegrass varieties.Keywords: fat-corrected milk, Lolium, milk solids, pasture, Pennisetum clandestinum

Made available in DSpace on 2018-12-11T17:15:08Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-10-03 The challenge of agricultural sector is to reduce greenhouse gas (GHG) emissions while increasing food, fiber and energy production without jeopardizing environmental integrity. In the Andean zone of Colombia, there is a growing need to develop GHG mitigation techniques associated with milk production. The present study focuses on GHG emissions and potential sinks associated with milk production scenarios in the Andean zone of Colombia. The scenarios considered were as follows: conventional agriculture of Pennisetum clandestinum in rotation with potatoes (PRP), improved pastures of Lolium multiflorum (IP) and silvopastoral system of P. clandestinum in association with Acacia decurrens and Trifolium repens (SPS). Based on the IPCC (Guidelines for national greenhouse gas inventories. The intergovernmental panel on climate change, Institute for Global Environmental Strategies, Kanagawa, 2006. http://www.ipcc-nggip.iges.or.jp/support/Primer_2006GLs.pdf) methodologies, the annual GHG emissions considering a 6-year production cycle included agricultural sources and gasoline consumption related to the most important agricultural phases in the field, and a potential for soil carbon accumulation and biomass carbon fixation in all the studied scenarios. The lowest GHG emissions were estimated in PRP scenario (3684 kg CO2-eq ha−1 year−1), which also presented additional emissions because of soil carbon losses beyond the lower milk productivity. Highest GHG emissions were observed in IP scenario (7711 kg CO2-eq ha−1 year−1), which exhibited the highest milk productivity and a considerable potential for soil carbon accumulation that could help to offset its emissions. Nevertheless, SPS scenario, which had milk productivity close to that of IP, presented the highest potential to offset the total GHG emission (4878 kg CO2-eq ha−1 year−1) because of soil carbon accumulation and biomass carbon fixation in trees. This study contributed to indicate management strategies that should be prioritized to mitigate the main sources of GHG emission in the extensive and intensive dairy cattle production in the Andean region of Colombia. Department of Exact Sciences College of Agricultural and Veterinarian Sciences São Paulo State University FCAV/UNESP), Via de Acesso Prof. Paulo Donato Castellane s/n Department of Rural Development Centro do Ciências Agrárias Federal University of São Carlos (UFSCar), Rodovia Anhanguera, km 174 Brazilian Bioethanol Science and Technology Laboratory/Brazilian Center for Research in Energy and Materials (CTBE/CNPEM), Rua Giuseppe Máximo Scolfaro 10000, Polo II de Alta Tecnologia Department of Exact Sciences College of Agricultural and Veterinarian Sciences São Paulo State University FCAV/UNESP), Via de Acesso Prof. Paulo Donato Castellane s/n

Development of a soil quality index for kikuyu (Pennisetum clandestinum)–ryegrasss (Lolium spp.) pasture systems in the southern Cape of South Africa is important since there are certain warning signs that their sustainability is being threatened. A total of 142 pastures throughout the region were sampled and several soil physical, chemical and biological indicators were quantified. A minimum data set of the most sensitive indicators was chosen using principal component analyses. Linear scoring functions for these indicators were used to develop a soil quality index. The most sensitive indicators were: extractable P > gravel content > water holding capacity (WHC) > exchangeable acidity (EA) > soil organic matter (SOM) = penetration resistance (PR) > exchangeable Mn. The soil quality index (SQI) was equated as: SQI = 0.13 (PR) + 0.16 (Gravel) + 0.15 (WHC) + 0.14 (EA) + 0.17 (P) + 0.12 (Mn) + 0.13 (SOM). This soil quality index is appropriate for pasture systems in the southern Cape of South Africa, and may be useful for similar pasture systems in other areas.

Kikuyu (Pennisetum clandestinum)–ryegrass (Lolium spp.) cultivated pastures form the base for dairy production in the southern Cape region of South Africa. The impact of various methods and implements used to over-sow ryegrass on the productivity and botanical composition of the pasture is unknown. The study aimed to assess the impact of cultivation along a soil disturbance gradient on the productivity and botanical composition of kikuyu-based pastures. Five tillage treatments were assessed, namely kikuyu over-sown with ryegrass using a minimum till planter, eradication of kikuyu with herbicide and ryegrass sown with a minimum-till planter, shallow ( 150 mm) disturbance with a rotavator or conventional tillage, respectively, and a control. The autumn, spring, summer and annual productions of treatments with the least soil disturbance were the highest (P ≤ 0.05). Shallow or deep tillage resulted in intermediate annual productions and the lowest (P ≤ 0.05) was recorded for the herbicide t...

Pasture-based automatic milking systems (AMS) require cow traffic to enable cows to be milked. The interval between milkings can be manipulated by strategically allocating pasture. The current experiment investigated the effect of replacing an allocation of grazed pasture with grazed soybean (Glycine max) with the hypothesis that incorporating soybean would increase voluntary cow traffic and milk production. One hundred and eighty mixed age, primiparous and multiparous Holstein-Friesian/Illawarra cows were randomly assigned to two treatment groups (n = 90/group) with a 2×2 Latin square design. Each group was either offered treatments of kikuyu grass (Pennisetum clandestinum Hoach ex Chiov.) pasture (pasture) or soybean from 0900 h to 1500 h during the experimental period which consisted of 2 periods of 3 days following 5 days of training and adaptation in each period with groups crossing over treatments after the first period. The number of cows trafficking to each treatment was similar together with milk yield (mean ≈18 L/cow/d) in this experiment. For the cows that arrived at soybean or pasture there were significant differences in their behaviour and consequently the number of cows exiting each treatment paddock. There was greater cow traffic (more cows and sooner) exiting pasture allocations. Cows that arrived at soybean stayed on the allocation for 25% more time and ate more forage (8.5 kg/cow/d/allocation) relative to pasture (4.7 kg/cow/d/allocation). Pasture cows predominantly replaced eating time with rumination. These findings suggest that replacing pasture with alternative grazeable forages provides no additional incentive to increase voluntary cow traffic to an allocation of feed in AMS. This work highlights the opportunity to increase forage intakes in AMS through the incorporation of alternative forages.

Some factors affecting yield of pastures grown in a water harvesting project on a solodic soil were investigated at Lawes in south eastern Queensland. In view of the low and erratic rainfall (30 inches per annum) and the low nitrogen status of the soil, experiments were designed to assess the relative importance of these limitations. Eight levels of ammonium sulphate (O to 48 cwt per acre) were applied to green panic (Panicum maximum var trichoglume K.Schum. Eyles) grown under natural rainfall and under irrigation for one year. Without ammonium sulphate, control plots produced 0.97 tons dry matter per acre, while irrigated plots produced 1.16 tons per acre. Highest yields were produced with 32 cwt per acre of ammonium sulphate, and, on these plots, yields for natural rainfall and irrigation were 7.3 and 8.3 tons per acre respectively. Green panic failed to persist except at high levels of ammonium sulphate, and was displaced by rhodes grass (Chloris gayana Kunth). Four levels of water and nitrogen were applied to kikuyu (Pennisetum clandestinum Hochst.) in spring, and produced essentially the same result - a marked response to nitrogen and a small response to water. There were no water-nitrogen interactions in either experiment. Thus, on this soil type at Lawes, nitrogen deficiency limits grass yield to a much greater extent than low rainfall. In both experiments, nitrogen greatly increased water use efficiency, while irrigation had the opposite effect. Nitrogen was most efficient in promoting growth when applied at rates of 200 to 400 lb per acre when extra yields of 30 to 40 lb dry matter per lb nitrogen were obtained. Rhodes and green panic grew rigorously over the period November to March, while kikuyu appeared to make more growth in autumn and spring. Green panic and kikuyu were grown in adjacent areas with ample water and nitrogen over a period of one year. Dry matter production from kikuyu exceeded a rate of 60 lb per day for 33 weeks, while the corresponding period for green panic was 18 weeks. On plots cut each 6 weeks, kikuyu produced 25,800 lb dry matter per acre, while green panic produced 14,900 lb per acre. At Lawes, dry spells of 12 days or more are likely to occur in every month of the year. In a field experiment, dry spells of 14 days reduced yield of siratro (Phaseolus atropurpureus D.C.) by one half compared with plots subjected to dry spells of 7 days. Nedulation and nitrogen production in tops were similarly affected. Thus, for the species tested, the response to irrigation was much greater with the legume than with grasses. The productivity of a number of pasture mixtures was compared under irrigation with an ample supply of nutrients. Farmyard manure was added to plots of temperate species to aid establishment. Rhodes grass was used as the companion species for each of the following legumes : lucerne (Medicago sativa L.), white clover (Trifolium repens L.), subterranean clover (T.subterraneum L.), siratro, and four cultivars of glycine (Glycine javanica L.). Over the two years of the experiment, lucerne plots were the most productive in terms of dry matter yield and nitrogen production in tops. In the second season, dry matter yields of grass and legume in lucerne, siratro, and glycine (CPI 23411) plots were 2.96, 2.42, and 2.43 tons per acre, while nitrogen yields in tops were 177, 144, and 144 lb per acre respectively. However, glycine failed to persist, and production from glycine and siratro was limited to the period November to April inclusive, while lucerne continued to grow through winter at the rate of 11 lb per acre per day. Following a severe drought in 1964-65, lucerne and siratro showed excellent persistence, while the other legumes were virtually eliminated. Lucerne and kikuyu emerged as the species showing greatest potential for use in water harvesting schemes, and pastures of kikuyu, rhodes and lucerne, and rhodes and siratro were shown to compare favourably in dry matter production with pastures grown in water harvesting situations elsewhere.

The volcanic cones of Auckland are distinctive landmarks of that city, currently realized as an ‘archipelago’ of grassy reserved hills. Most of these cones were modified as hill forts during former occupation by Māori. Here, we review the Auckland volcanic reserve network and survey the current groundcover vegetation and soils of four large representative examples. Forty-eight reserves currently occur on remnant volcanic features. As well as two inshore island reserves (2372 ha), the other 46 reserves total 1241 ha. Most of the volcanic reserves support exotic grassland with rare forest patches. Groundcover vegetation follows a topographic sequence from flatter, fertile sites dominated by Lolium perenne, Trifolium repens and Pennisetum clandestinum, to moderately steep sites dominated by a diverse range of exotic grasses, to steep, lower fertility sites dominated by Microlaena stipoides. Pennisetum clandestinum is a major component of groundcover vegetation on many sites across all slope classes, its abun...

a b s t r a c t High concentrations of sodium are toxic to most plant species, making soil salinity a major abiotic stress for plant productivity world-wide. Its salinity resistance makes the turf grass Pennisetum clandestinum Hochst (kikuyu grass) a candidate plant for utilization and reclamation of salinized areas. Kikuyu grass, a perennial native to the highlands of Central Africa now common in many areas, has recently become a valuable pasture and lawn plant because of its growth rate and well developed root system. However, its salt resistance has yet to be fully evaluated. The objective of this study was to identify the biochemical and physiological basis of salt resistance of kikuyu grass for the use of this grass as pasture, in phytoreme- diation, in controlling soil erosion and in biomass production for energy, in salt affected lands, where the growth of other species is markedly reduced. This study focused on the effect of salinity on germination, growth, metabolism, biochemistry, nutritive properties and root morphology of kikuyu grass. We com- pile evidence that kikuyu grass can germinate and grow in salinized areas. The use of this salt-tolerant grass may be an important part of a range of practices, such as recycling saline wastewater and reclaiming salt-affected soil in arid-zone irrigation districts. © 2012 Elsevier B.V. All rights reserved.

Forages cover extensive areas of agricultural land in Australia, but only limited data is available on the potential of these different forages to sequester soil organic carbon (SOC) under best practice management. This study was undertaken on a brown dermosol in the warm temperate climate of Camden, Australia, over three years, to evaluate a range of perennial and annual forages for their impact on SOC and soil nitrogen (N). The C4 perennial forages kikuyu (Pennisetum clandestinum Hochst. ex. Chivov.) and paspalum (Paspalum dilatatum Poir.) increased (P 0.05). The high productivity of legumes led to high mean estimate of N fixation of up to 726 kg N ha/year over the three years. However, as most of the legume shoot production of the forage species was removed there, was a negligible increase in soil N levels. This study has shown that the choice of forage has a large impact on the amount of carbon that can be sequestered into the soil.

Pennisetum clandestinum (kikuyo) es una pastura común en los sistemas silvopastoriles del altiplano cundiboyacense, con altas propiedades nutritivas. Por tanto estudios que permitan mejorar el proceso de producción en términos económicos y ambientales reviste gran importancia. En este estudio se evaluó el papel de la inoculación con bacterias promotoras de crecimiento vegetal (PGPR) sobre el crecimiento de pasto kikuyo. Las cepas 4K y 5B fueron identificadas mediante amplificación y análisis del 16S rADN, como Stenotrophomona ssp. y Pseudomona ssp., respectivamente, caracterizadas por su eficiencia in vitro en la fijación biológica de nitrógeno, producción de compuestos indólicos y solubilización de fosfatos. Se evaluaron las cepas en condiciones de invernadero en tres tiempos de crecimiento de la planta (70, 100 y 130 días). Se evidenció que la cepa 4K incrementó el peso seco radicular de la planta en 50% a los 70 y 100 días, mientras que la cepa 5B mostró un comportamiento similar en el peso seco aéreo y radicular con aumentos de hasta el 50% a los 130 d. El efecto más importante se presentó después de 100 d donde los tratamientos TQ, TB1 y TB2, superaron en más del 80% al testigo absoluto en el peso fresco de la parte aérea. Estos resultados demostraron que la inoculación de PGPR representa una alternativa biotecnológica para promover el crecimiento de P. clandestinum, con efectos relevantes en producción de biomasa 100 días después de la siembra (dds).

Suitability of the Natural Resources Conservation Service (NRCS) curve number (CN) model of run-off prediction was evaluated on three humid tropical forested catchments in Kimakia, Kenya. The catchments were dominated by Pinus patula (catchment A), Arundinaria alpina (catchment C) and Pennisetum clandestinum (catchment M). The study used discharge and rainfall data collected between 1958 and 1986. Seventy-three (73) isolated storms were graphically separated into baseflow, interflow and surface run-off. Forest cover types significantly improved catchments characteristics that influence baseflow and interflow generation in catchment C but not those that influence surface run-off production. In its original form, the NRCS CN model resulted in direct run-off estimates that deviated from observed ones by between 43.8% and 55.3%. These discrepancies were minimized through modification of the β and CN parameters. CN generated empirically using storm rainfall predicted the direct run-off satisfactorily. Therefore, the modified NRCS CN model adequately estimates direct run-off from humid tropical forested catchments.

Widden Brook in the Hunter Valley, Australia, was first settled by Europeans in 1831 and had widened substantially by the 1870s due to frequent floods during a flood-dominated regime impacting on highly disturbed banks whose riparian trees had been either ringbarked or cleared, and whose understorey had been grazed. Catastrophic floods in 1950 (many), two in August 1952 and one in February 1955 effected the final phase of channel widening at the onset of a second flood-dominated regime more than half a century after the initial widening. Contraction has been active since 1963 by a combination of five biogeomorphic processes. Firstly, rapid channel widening, migration and cutoffs totally reworked the pre-European floodplain and were followed by active floodplain formation. Initial bar formation was replaced by sand splay and overbank deposition which constructed a new floodplain and narrower channel. Secondly, overwidened channel segments that were produced by the catastrophic 1955 flood have contracted since 1963 by the formation of up to four bank-attached, discontinuous benches below the floodplain. Each bench has a bar nucleus of pebbly coarse sand overlain by stratified fine-medium sand and mud. Colonisation by River Sheoaks (Casuarina cunninghamiana subsp. cunninghamiana) or grasses (Cynodon dactylon, Paspalum distichum, Pennisetum clandestinum) is important in converting bars to benches. Thirdly, narrower segments which developed since 1963 have contracted by small-scale accretion on both banks. These deposits are steeply dipping, interbedded sand and mud trapped by stoloniferous and rhizomatous grasses (C. dactylon, P. distichum, P. clandestinum) which also rapidly stabilise the deposits. Fourthly, rare laterally migrating, small radius bends have contracted by recent point bar formation greatly exceeding cutbank recession rates. Point bar formation is controlled by secondary currents producing inclined stratified coarse sands without the influence of vegetation. Lastly, rare, overwidened, non-migrating, large radius bends have greatly contracted by the infilling of dissecting chutes across the convex bank. Establishment of stoloniferous and rhizomatous clonal grasses (Phragmites australis, C. dactylon, P. distichum, P. clandestinum) is important in inducing sedimentation of the chutes. Contraction has produced a much narrower channel than the design width between river training fences which were installed progressively between the 1960s and 1990s. The recent flood history of Widden Brook has not included any catastrophic floods of a size similar to February 1955. Our work demonstrates that both trees and grasses can be associated with narrower channel widths and that the causal link between width and vegetation type is more complex than usually acknowledged.

Management plans for the grazed parklands of the Auckland volcanic cones call for revegetation to restore a more natural and historic vegetation cover. The native grass Microlaena stipoides has been identified as a relevant species, and a field experiment was undertaken to determine the best approach for establishing this species into existing pasture. Seed obtained locally was broadcast or hydro-seeded in May 2007 onto kikuyu pasture, at three sowing rates (100, 250 and 750 seeds/m2) following control of the resident pasture with turf stripping or mowing and spraying, in a replicated factorial trial. After 12 months, the highest levels of Microlaena plant density (mean 56 plants/m2), cover (mean 50%) and accumulated herbage mass were observed on broadcast/sprayed plots at the highest sowing rate. Recovery of the resident pasture (dominantly Pennisetum clandestinum) occurred to a level of ~25% after 12 months, but was inhibited at the highest Microlaena sowing rate. Keywords: broadcast, hydro-seeding, kikuyu, Microlaena stipoides, re-vegetation

En esta investigación se determinó el balance de nitrógeno en dos tipos de pasturas de clima frío: una pastura mixta de dos gramíneas -kikuyo (Pennisetum clandestinum) y festuca alta (Festuca arundinacea)- y pastura asociada de la gramínea festuca alta más la leguminosa trébol pata de pájaro (Lotus uliginosus), en un área de 1 ha cada una, con un diseño al azar con la vaca como unidad experimental y la pastura como tratamiento. Se emplearon cinco vacas Holstein para cada tratamiento durante un período experimental de 14 días. Se determinó la producción de biomasa (g MS/m2), cantidad de nitrógeno en la pastura, suplemento, salidas en heces, orina y leche, y el valor de eficiencia de uso del nitrógeno por los animales. En el balance del nitrógeno en el animal, se observó mejor eficiencia en su uso en la pastura asociada comparada con la pastura mixta, y cambios en las vías de excreción, siendo mayor la salida en orina de los alimentados con pastura mixta y mayor en leche en los alimentados con la asociada. El balance de nitrógeno en la pastura in situ se realizó con un modelo de simulación, empleando los valores determinados en este ensayo, y se observó que fue positivo para la pastura asociada frente a la mixta; esto indica menor necesidad de nitrógeno externo en la pastura asociada. La pastura asociada mejoró la eficiencia de uso del nitrógeno en ganado para leche y presentó un balance positivo en el sistema de pastura.

A monitoring programme for the tropical grass webworm (TGW) (Herpetogramma licarsisalis) has been operating in the Far North since 1999, when high densities of the larva resulted in severe defoliation of large areas of kikuyu (Pennisetum clandestinum) pasture. Keywords: tropical grass webworm, kikuyu, pheromone, monitoring programme

The high dry matter yield of kikuyu (Pennisetum clandestinum) under favourable conditions supports high stocking rates and milk production per hectare. However, the quality of kikuyu is generally low and consequently the milk production per cow is also low. The aim of the study was to determine the grazing capacity, milk production and milk composition from kikuyu, kikuyu over-sown with annual ryegrass (Lolium multiflorum var. westerwoldicum), kikuyu over-sown with a mixture of perennial ryegrass (L. perenne), white clover (Trifolium repens) and red clover (T. pratense), and kikuyu over-sown with a mixture of white and red clovers. Milk production per cow was highest on pasture with high clover content and the grazing capacity of pasture increased as the grass component increased. The milk produced from kikuyu during spring (15 kg cow–1 d–1) and summer (14.4 kg cow–1 d–1) was higher than during the autumn (12.1 kg cow–1 d–1). The total milk production from kikuyu during spring (3 876 kg milk ha–1) increased when kikuyu was over-sown with annual ryegrass (8 133 kg milk ha–1) or with clover (7 370 kg milk ha–1). The summer and autumn grazing capacity of kikuyu and kikuyu–annual ryegrass fertilised with nitrogen was higher than the kikuyu–clover pastures not receiving nitrogen. The clover content of the pastures did not affect the milk protein or butterfat content. The mean annual grazing capacity of kikuyu (6.7 cows ha–1) and kikuyu–annual ryegrass (8 cows ha–1) pasture was higher than the kikuyu clover (5.3 cows ha–1) pasture. The grazing capacity and milk production per cow from kikuyu over-sown with ryegrass varied less than from kikuyu or kikuyu–clover pastures. This resulted in a similar or higher milk production per hectare from kikuyu–ryegrass compared to that of kikuyu or kikuyu–clover pastures. Keywords: annual ryegrass, butterfat, kikuyu, milk, milk protein, perennial ryegrass, red clover, white cloverAfrican Journal of Range & Forage Science 2008, 25(3): 103–110

Summary Warm-season grasses and legumes have the potential to provide forage throughout the Mediterranean summer when there are high temperatures and low rainfall and when cool-season grasses become less productive. Twenty-nine non-native, warm-season pasture species (twenty-three grasses and six legumes) were assessed for their adaptability to the coastal plain of southern Italy in terms of their productivity and nutritional quality. The investigated species were compared with two reference species widely used in a Mediterranean environment: a grass (Festuca arundinacea) and a legume (Medicago sativa). The species differed in their phenological and biological characteristics, i.e. start of vegetative resumption, first flowering and cold resistance, from each other and from the control species. From the second year after establishment, warm-season perennial grasses had high dry-matter (DM) yields and, in many cases, a more than adequate nutritional quality. As for legumes, the control, M. sativa gave the best results in all the investigated characters. Among the grasses, seven species (Chloris gayana, Eragrostis curvula, Panicum coloratum, Paspalum dilatatum, Pennisetum clandestinum, Sorghum almum, Sorghum spp. hybrid) had DM yields greater than the control species and had their maximum growth during the hottest period of the year, when F. arundinacea, the control grass species, was dormant. Eragrostis curvula had the highest annual DM yield (21·1 t ha−1) and P. clandestinum provided the best combination of agronomic and yield characteristics which were similar to those of M. sativa. The seven above-mentioned species have the potential to supply hay or grazing and contribute to broadening and stabilizing the forage production calendar in Mediterranean-type environments.

In this study, the effect of increasing the proportion of concentrate in the diet, on efficiency of feed utilisation, was determined when Holstein–Friesian cows grazed short-rotation ryegrass (Lolium multiflorum) or kikuyu (Pennisetum clandestinum) pastures. The concentrates were energy-dense dairy pellets fed twice-a-day at milking and the roughage component was lucerne hay and the pasture. When cows grazed ryegrass, there was no effect on animal performance as the proportion of concentrate in the diet increased from 0.23 to 0.35 (4.75 to 7.50 kg concentrate/cow/day). The substitution rate of concentrates for pasture for the first 1.57 kg concentrate/cow/day fed was 0.58 but rose to 1.18 for the next 1.28 kg concentrate/cow/day. When cows grazed kikuyu, there was also no effect of increasing the proportion of concentrate in the diet on total dry matter intake (DMI) or milk production. However, there was a substantial increase in the in vivo digestibility of whole diet, pasture and acid detergent fibre (ADF) was observed when the proportion of concentrate in the diet increased from 0.08 to 0.25. However, there was a marked decline in pasture digestibility (72% to 64%), and more so in ADF digestibility (61.3% to 48.4%), as the proportion of concentrate in the diet increased further to 0.29 (5.52 kg/cow/day). The intake of kikuyu, when determined by difference between pre- and post-grazing pasture mass, was substantially underestimated compared to the use of the n-alkane technique, and this discrepancy increased as the pasture on offer increased. On both pasture types, the neutral detergent fibre intake, as a % of bodyweight varying from 1.6% to 2.2% for kikuyu and 1.5% to 1.6% for ryegrass was far above the values claimed of 1.2% to restrict intake. The results of this study highlight the limits to the amount of concentrate that can be fed on a typical Australian dairy farm where concentrates can only be fed twice-a-day at milking. The results also provide a more appropriate benchmark for fibre limitation in the ration when cows graze pasture, particularly poorer quality tropical grasses, and this value is well above that found in more intense feeding situations.

Yearling Hereford and Holstein-Friesian heifers were grazed on kikuyu pasture during summer and the intake and apparent digestibility were estimated using the n-alkane procedure. There were eight animals of each breed. The trial was conducted during the last two weeks of January at the Cedara Research Station in the KwaZulu-Natal mist-belt of South Africa. The animals were on a continuous grazing regime at a stocking rate of four heifers per hectare. Herbage availability was estimated using a disc meter at about 1545 kg dry matter (DM) per hectare. Crude protein (CP), acid detergent fibre (ADF) and neutral detergent fibre (NDF) in hand plucked samples were estimated at 179 g/kg DM, 332 g/kg DM and 667 g/kg DM, respectively. The Herefords had a 22% higher intake (P 0.05), which was on average 0.58.

Con el propósito de evaluar la calidad nutricional en ensilajes de follaje de árboles como fuentes forrajeras altemativas para ganado lechero se realizó una simulación productiva y económica de un hato lechero de la Sabana de Bogotá. Para la simulación se utilizó la información del hato lechero del C. I. Tibaitatá aplicando el modelo Comell Net Carbohydrate and Protein System (CNCPS). La base alimenticia del hato fue pastoreo libre de Pennisetum clanilestinum (Kikuyo) suplementado con seis tipos diferentes de ensilaje (T1 a T6) a base de follaje de Sambucus peruoiana, Acacia Decurrens y Avena sativa, tratados con ácido fórmico al 85%, extracto enzimático y el producto comercial Kem Lac®*. Las dietas de ensilajes tratados con extracto enzimático presentaron el mejor desempeño productivo y económico en la simulación, así: (T3) 1,8 L/día e ingreso neto diario de $7.216 por vaca; (T1) 18 L/día e ingreso neto diario de $7.623 por vaca; y (T6) 1,8.2 L/día e ingreso neto diario de $ 6.146 por vaca. Cuando se adicionó melaza de caña, la respuesta en T3 fue de 229 L/día y $ 9.548 de ingreso neto vaca/día, con una tasa de retomo marginal de 65.5%. E sta respuestas e atribuyó a la mayor eficiencia en la utilización de los nutrientes y al adecuado sincronismo de éstos en el rumen, que se reflejó en un incremento de la proteína de origen microbial y en un equilibrio adecuado de péptidos ruminales estimados en la simulación. * Kem Lac®: Kemin lrdustries, Inc. 2100 Maury St., Box 70. Des Moines, AL USA. 50031-0070.515/226-2111.

The effects of agricultural land use [kikuyu pasture (Pennisetum clandestinum), annual ryegrass pasture (Lolium multiflorum). maize (Zea mays), preharvest burnt sugarcane (Saccharum spp.) and undisturbed native grassland] on the catabolic diversity of soil microbial communities were determined using Biolog Grain Negative (GN) microplates or a substrate-induced respiration (SIR) technique. These techniques were also used to determine catabolic diversity in sugarcane soil under long-term preharvest burning or under green cane harvesting with retention of a trash mulch (with or without annual fertilizer additions). Principal component analysis (PCA) of Biolog data revealed large differences in catabolic capability of soil microbial communities between burnt sugarcane, annually tilled (annual ryegrass and maize) and non-tilled grass (kikuyu pasture and native grassland) land uses. For SIR data, differences in catabolic capability existed between all land uses. PCA of Biolog data showed large differences in catabolic capability between sugarcane soil under trashing and preharvest burning but there was little effect of fertilizer applications. However, for SIR data, differences due to both trashing versus burning and fertilizer versus no fertilizer were evident. For Biolog data values for Shannon's diversity index followed the order: kikuyu pasture = native Grassland = ryearass pasture > maize = burnt sugarcane and trashed sugarcane had higher values than burnt sugarcane. For SIR data, substrate richness was similar between treatments and catabolic evenness followed the order: native Grassland > kikuyu pasture > ryegrass pasture > maize = burnt sugarcane and was greater for trashed than burnt sugarcane. It was concluded that the SIR method was more effective at separating treatments with broadly similar land uses and managements than the Biolog method. In general, land uses and managements that increased soil organic matter tended to increase catabolic diversity. (c) 2004 Elsevier B.V. All rights reserved.

The effects of land management including undisturbed native forest, native grassland, sugarcane (Saccharum spp.) (pre-harvest burnt or green cane harvested), exotic forest (gum, Eucalyptus grandis; pine, Pinus elliottii; wattle, Acacia mearnsii), orchard crops (orange, Citrus sinensis; banana, Musa accumunata; avocado, Persea americana) and grazed kikuyu grass (Pennisetum clandestinum) on the size and composition of earthworm communities and on related soil properties (organic C, soluble C, microbial biomass C) were investigated. The study locality was in the tropical, northern part of KwaZulu-Natal. Earthworm numbers followed the order: kikuyu pasture > native forest > banana > orange > wattle = pine = gum = green cane harvested sugarcane > native grassland = avocado greater than or equal to burnt sugarcane. Earthworm numbers and biomass were closely positively correlated with soluble C, microbial biomass C and also pH. A total of 11 species of earthworms were collected. Over 80% of individuals collected were accidentally introduced exotic species which originated from India, South America and West Africa. Most land use types supported five to seven species but sugarcane and wattle supported only two or three species. Juveniles dominated the community under all land uses except kikuyu pasture and avocado. Epigeic species dominated under native forest and native grassland, avocado and gum. For the other types of land use, endogeics predominated. The most numerous species present was Pontoscolex corethrurus which was present under all land uses. The most common epigeic species was Amynthus rodericensis which made up a substantial portion of the community under native and gum forests and banana. The third most numerous species was A. minimus which is a polyhumic, endogeic species and was particularly numerous under kikuyu pasture. Dichogaster saliens was an important component of the community under some land uses. It was concluded that land use has major effects on the size, composition and diversity of earthworm communities in the region. (C) 2004 Published by Elsevier B.V.

Although the effects of land use on soil organic matter are well known, the effects on the size, activity and diversity of the soil microbial community are less well documented. In this study the effects of agricultural land use (maize (Zea mays), annual ryegrass (Lolium multiforum), permanent kikuyu grass pasture (Pennisetum clandestinum), gum (Eucalyptus grandis) and pine (Pinus patula) forest) on microbial biomass C, microbial and exocellular enzyme activity and heterotrophic functional diversity (by analysis of catabolic response profiles to 36 substrates) was investigated on a site where the long-term history of land management was known. In comparison with native grassland, permanent kikuyu pasture resulted in an increase in organic C, microbial biomass, arginine ammonification rate, flourescein diacetate hydrolysis rate and arylsulphatase activity. By contrast, under maize under both conventional tillage (CT) and zero tillage (ZT) and annual ryegrass there was a reduction in organic matter and microbial biomass content and in measurements of microbial and enzyme activity. However, in these three arable soils, basal respiration, arginine ammonification and fluorescein diacetate (FDA) hydrolysis rates, when expressed per unit of microbial biomass, were higher than under the other land uses, suggesting the presence of a small but highly metabolically active microfloral community. Soils below pine forest tended to have a higher organic C content than those below gum forest, yet microbial biomass C, basal respiration, arginine ammonification rate and arylsulphatase activity were lower under pine forest. This was attributed to the inhibitory effects if phenolic compounds in pine needles. Principal components analysis of catabolic response profiles demonstrated that there were large differences in the catabolic capability of the soil microbial communities inhabiting the various land use types. Values for Shannon's and Simpson's diversity indices followed the order: pine < gum < kikuyu pasture = annual ryegrass = maize (ZT) = maize (CT) < native grassland indicating that greatest catabolic diversity existed under native grassland and least diversity existed under exotic forest. It was concluded that land use had substantial effects on the size, activity and diversity of the soil microbial community and that these changes could be broadly related to changes in soil organic matter content. (C) 2004 Elsevier B. V. All rights reserved.

The effect of four carbohydrate supplements on the productivity of dairy cows grazing short rotation ryegrass (Lolium multiflorum) or kikuyu (Pennisetum clandestinum) pastures were assessed. When grazing kikuyu, four groups of 20 cows (14 in early and 6 in late lactation) were matched for production and live-weight and were supplemented with 4 kg dry matter (DM)/cow day of either finely rolled barley (B), finely rolled barley sucrose mix (ratio 3:1) (BS), cracked maize (M) or finely milled rice (R), over a 35-day experimental period following a 21-day adjustment period. The production of cows in early (P

Methane emission was measured from 10 dairy cows and 12 wether sheep grazing kikuyu grass‐ (Pennisetum clandestinum) dominant pastures at Waimate North, Northland, in February 1997 and March 1999, and from 10 dairy cows grazing summer grass‐ (Digitaria sanguinalis) dominant pasture at Edgecumbe, Bay of Plenty, in March 2000. Methane emission was measured from each animal for 5 consecutive days in each measurement period using the sulphur hexafluoride (SF 6 ) tracer gas technique. Analysis of variance of the kikuyu grass chemical composition with sheep and cow data combined showed that the 1999 pastures were significantly higher in protein (P < 0.01), soluble sugars (P < 0.001), lipid (P < 0.01), and dry matter (DM) digestibility (P < 0.001) and lower in ash (P = 0.023), acid detergent fibre (ADF) (P < 0.001), and neutral detergent fibre (NDF) (P < 0.001) than the 1997 pastures, presumably as a consequence of urea topdressing in 1999. The chemical composition of the summer grass‐dominant pasture g...

A large proportion of the nutrients ingested by grazing animals are returned to the pasture in dung and urine. These by-products of animal digestion contain many ingredients necessary for plant growth, including nitrogen (N), phosphorus (P) and potassium (K). Disadvantages include a tendency for K levels to increase in soils where large quantities of animal waste are applied. A field study was undertaken on kikuyu pastures on the Cedara Research Station in the Midlands of KwaZulu-Natal in order to evaluate the effects of excretal returns on animal performance and soil properties. Two treatments (T1 and T2) involved no overwintering on kikuyu, followed by no N fertilisation during summer (T1) or the application of 250kg of N/ha during the summer (T2). The third treatment comprised overwintering on the kikuyu with no N fertilisation during the subsequent summer (T3). Overall, initial live mass of the trial animals was 221.6 ± 3.1kg and the live mass gain was 67.6 ± 3.1, 96.2 ± 3.1 and 80.7 ± 3.1kg per steer for T1, T2 and T3 respectively. As expected, the K levels in the soils of the dunged pasture increased. Before N fertilisation of kikuyu pastures with a relatively high fertility status is undertaken, overwintering cattle on the pastures should be considered. Fertiliser N should only be applied if the expected increased return in livestock sales is greater than the cost of the N fertilisation. Keywords: increased potassium; dung; excreta African Journal of Range & Forage Science 2001, 18(1): 31-35

Pasture fertilization affects plant growth and animal production, and it may influence the redistribution and cycling of nutrients excreted in dung and urine. Kikuyugrass (Pennisetum clandestinum Hochst. ex Chiov.) pastures on a high organic carbon (C) Typic Hydrudand soil with and without (control) annual nitrogen (N) and periodic phosphorus (P) and potassium (K) fertilizations were stocked with Hereford and crossbred cattle (Bos taurus) for 33 years. The pastures were divided into 1.2-ha paddocks for rotational stocking after the 15th year. Selected fertilized paddocks that were uniformly managed over the years were paired with control paddocks to determine management effects on soil organic C; soil and plant N, P, and K; and earthworm distribution. Responses were assessed using a zonal sampling procedure based on distance from the waterer because the paddocks lacked shade. Soil organic C, organic N, and organic P did not statistically differ between managements or zones in any horizon. Relative to the ...

The presence of Herpetogramma licarsisalis (tropical grass webworm) larvae in pasture 40 km north of Kaitaia on the Aupouri Peninsula, Northland New Zealand was confirmed in March 1999. A survey was undertaken in late March 1999 using spade sampling and sack survey techniques. The main locus of infestation (ca.37,000 ha) was centred on Pukenui, and a secondary infestation (30-40 ha) was identified 20 km south of Cape Reinga. Infestations were restricted to kikuyu (Pennisetum clandestinum) pastures. H. licarsisalis population densities declined over the winter (June - September 1999). In March 1999 larvae were present at 64% of sites sampled but by early September 1999 were only present at 7% of sites sampled. Sites where H. licarsisalis were present in July and September 1999 were characterised by well drained north facing slopes. In Northland, H. licarsisalis is at the limits of its geographical range. The possibility that this is a shortterm establishment and sporadic event is discussed.

This paper describes a Tropical Pasture Simulator. This is a simple mechanistic model representing the growth of vegetative tropical pastures under rotational or continuous grazing with responses to N fertiliser, temperature and irradiance that can be used as a tool to study management options for the development of sustainable grazing systems. The model was derived as an adaptation of the ‘Hurley pasture models’ which were originally designed to simulate the growth of ryegrass. The model incorporates the processes of light interception and photosynthesis, leaf area expansion; growth, ageing and senescence of plant tissues, recycling of substrates from senescing tissues, nitrogen uptake, mineralisation of soil organic N, N leaching and grazing. The paper discusses the main structure of the model, its components and the main adaptations required to simulate the growth of tropical pastures. The model was parameterised for kikuyu grass (Pennisetum clandestinum) growing in dairy systems in highland regions of Costa Rica. This paper also discusses the sensitivity of parameter values and the development of minimum parameter datasets for time and cost-eAective implementation of the model. # 2000 Elsevier Science Ltd. All rights reserved.

Twenty-four sheep were used to test breed and age differences in voluntary intake (VI). The sheep were divided into four groups of six animals each: Suffolk mature ewes (SM), Suffolk yearlings (SY), Rambouillet mature ewes (RM), and Rambouillet yearlings (RY). The animals grazed alternatively two mixed pastures containing Trifolium repens latum, Lolium perenne and Pennisetum clandestinum from 07:00 to 16:30 hours and remained penned overnight. Voluntary intake was estimated using chromic sesquioxide (1g per sheep) as an external marker, administered in two gelatin capsules, one before and one after grazing, during 65 days. Faecal grab samples were collected directly from each animal for three consecutive days beginning on Day 7 of the experiment and at 14-day intervals until Day 65 (sampling times=5). Hand-plucked samples of forage were used to estimate in vitro dry matter digestibilities (IVDMD), which were used with estimates of fecal output to calculate intakes (per animal and per kg of metabolic body weight (kg(0.75))). The data were analyzed as a completely randomized design in a factorial arrangement with repeated measurements. Voluntary intake, expressed both per animal and per kg(0.75), showed a breedxage interaction (P 0.05) from that of RY (0.063kgDM/day), which were smaller, younger animals. Suffolk yearlings and RM had similar VI/kg(0.75) (0.057 and 0.051kgDM/day, respectively), not different from that of the RY. Intakes showed a cubic trend (P

This paper presents validation results and some management applications of a Tropical Pasture Simulator. The eAects of diAerent environmental conditions, N fertilisation regimes and grazing intensities are analysed, and physiological concepts are used to aid in the interpretation of the responses obtained. The model demonstrates the importance of flexible management guidelines depending on environmental conditions. It stresses the need for an increased understanding of the processes controlling the development and senescence of the sward, since these largely influence the responses to nutrients and determine sward structure. Strategies based on morphological indicators such as number of live leaves were derived in order to develop simple and applicable pasture management guidelines at the farm level. Examples are presented with reference to kikuyu grass (Pennisetum clandestinum) production and utilisation in dairy systems in the highlands of Costa Rica. # 2000 Elsevier Science Ltd. All rights reserved.

The objective of this article is to offer some information about traditional practice regarding the use of the genus Buddleia in the Highlands of Chiapas, Mexico, with the aim of increasing its use as a potential fodder for sheep feeding in the area. Based on the indigenous Tzotzil Botanical Classification, three Buddleia groups were taxonomically identified. Group 1 includes the species Buddleia skutchii and Buddleia cordata, group 2, Buddleia americana and Buddleia crotonoides, and group 3, Buddleia parviflora and Buddleia nitida. Even though all these groups have been used as fodder, the most frequently used are the species in group 1, which are the most common species with the widest distribution patterns. Based on their chemical composition, the species of higher nutritional values were B. skutchii and B. crotonoides (crude protein (CP), 10.6% and 9.3%; neutral detergent fiber (NDF), 37.5% and 33.7%; in vitro dry matter digestibility (IVDMD), 75.9% and 58.2%; and digestible energy (DE), 3.3 and 2.5 Mcal/kg). The first one has been recommended for sheep feeding based on its high nutritional value. During an intake and digestibility trial, B. skutchii leaves substituted 50% of Kikuyo grass (Pennisetum clandestinum) without decreasing dry matter (DM) intake and digestibility. These results suggest that the systematic incorporation of B. skutchii into existing sheep production systems could markedly increase feed resources without higher pressure on pasture land.

Kikuyu pasture was grazed continuously for 12 months by 20 dry and 40 producing South African Mutton Merino (SAMM) and Merino ewes at a stocking density of 23 ewes ha−1. Supplementary sweet lupin seed was supplied to one group of producing ewes of each breed during pregnancy and lactation at a rate of 0.5% of the liveweights of the ewes. Rumen fluid samples for the determination of pH, volatile fatty acids (VFA), and ammonia‐nitrogen (NH3‐N) were collected from rumen‐fistulated wethers corresponding to the periods of late pregnancy and early lactation of ewes. Rumen NH3‐N concentrations (8.7 mg 100 ml−1 and 5.4 mg 100 ml−1) were low during both periods of sampling. Rumen VFA concentrations (12.3 mmol 100 ml−1 and 9.2 mmol 100 ml−1)were within normal ranges. Supplementation significantly increased blood urea concentration of ewes. Supplemented ewes lost less weight than the unsupplemented ewes (P ≤ 0.02) during the experimental period. Pregnancy (P ≤ 0.001) as well as lactation (P ≤ 0.0001) reduce...

Irrigated kikuyu pasture was continuously grazed for 12 months by 30 South African Mutton Merino (SAMM) and 30 Merino ewes at a stocking density of 23 ewes ha−1. Herbage samples for chemical composition were obtained monthly either by quadrat cuts or by oesophageally fistulated (OF) wethers. Intake was determined with controlled chromium release devices on eight dry and eight producing ewes from each breed during the periods of late pregnancy (February) and lactation (March). Significant (P ≤ 0.05) differences in the OM, OMD, CP, ADF, and NDF contents of manually collected and OF‐selected samples occurred between months. The means for CP, OMD, ADF, and NDF of the OF‐samples were, respectively, 18.3%, 62.3%, 37.8%, and 74.1% (expressed on an OM‐basis). During February, SAMM ewes (1184 ± 66 g d−1) consumed 27% (P = 0.01) more OM than Merino ewes (930 ± 66 g d−1), while there was no difference in intake between dry and pregnant ewes. During March, there were no differences in intake between breeds o...