Herbage mineral nutrition indexed as tools for rapid mineral status diagnosis in tropical pastures

The animal production sector in the tropics is increasingly becoming challenged with the limited availability of pastures. There is need therefore to explore other options to suppliment the available pastures. The objectives of this study therefore was to understand how herbage mineral dilution indices used in developed countries as tools for controlled fertilisation, could be adapted in a tropical environment where high seasonal variations with regard to availability occur in pastures. A 3-year study was carried out in La Réunion Island, Indian Ocean. Fortynine farms, with swards made of either temperate or tropical grasses, grazed or mowed, were visited between four and five times a year. Dry biomass and dry matter contents were reported at each sample collection; whereas mineral indices were calculated from chemical analysis with a view to generate relevant fertilisation recommendations.Although the dry matter ( DM) values of less than 20% indicated a better stage of exploitation for the grasses, the data consistently indicate a decrease in the seasonal differences of dry biomass for grazed species. The use of indices, which combine both plant mineral status and pasture biomass, appeared relevant indicators for farmers and for pasture experts in tropical countries, and can be predicted through near infrared spectroscopy with an acceptable precision (R2 = 0.80, 0.60 and 0.91, for nitrogen , phosphorous and potassium, respectively). With reduced cost of pasture feed analysis using the NIRS, farmers can be able to make informed decisions basedon scientific data. Fertilisation is one of the potential options to improve pasture management as indicated by findings of this study. This is useful evidence-based information that could be incorporated in extension packages and resource materials for dissemination and subsequent adoption by livestock farming communities to improve produtivity

Innovative Approaches to Analysing Carbon Sequestration as a Mitigation Strategy in Tropical Pasture Landscapes in Two Emblematic Contexts, the Amazon and the West African Sahel

The relationship between ruminant production systems and climate change is complex. As a major contributor to greenhouse gas (GHG) emissions, the sector has been the subject of considerable controversy, with particularly severe criticism in the 2000s. However, ten years ago, the attitude towards grazing lands began to change. Their efficient use of non-renewable energy and their contribution to carbon (C) sequestration were considered as key factors in the new environmental challenge. The reality of this mitigation potential was recently called into question once again in the global agriculture and climate change debate, including that of sequestration in the soil where grazing lands occupy a major position (30-40% of the land surface representing 30% of the soil organic C of the world). Few scientific references are available on these questions in tropical regions, and the standard metrics and methods used may turn out to be unsuitable for the correct evaluation of grazed ecosystems in these regions. Significant work is therefore required to establish baselines and design strategies to ensure sustainable grazing in these regions where the global sequestration potential is high relative to the surface areas concerned. To contribute to this debate, we focus on mitigation options offered by rangelands and grasslands and their management in two emblematic tropical contexts, humid and dry tropics, where field studies have been based on original and holistic approaches at different levels. In Amazonia, if curbing deforestation remains a priority, it needs to be accompanied by sustainable management of deforested areas. In the French Amazon (French Guiana), monitoring fields using chronosequences and flux towers has produced scientific knowledge on the significant mitigation capacities of grassland ecosystems. In the Brazilian Amazon, the spatial logic of the agro-ecological intensification of forage production has enabled a transition from individual extractive systems to farm management at communal levels. In the West African Sahelian region (Northern Senegal), an integrative study at landscape scale revealed the unexpected capacity of soil and shrubs for C sequestration that can offset the GHG emissions for which pastoralism in dry tropical zones is usually blamed

Restoring Value to Grassland Initiative: To Maintain the Environmental and Economic Value of Grasslands and to Promote Their Social and Cultural Functions

The Global Agenda for Sustainable Livestock (GASL), a multi-stakeholder partnership started in 2013 includes nine action networks (ANs). The networks are the working engine of GASL and are tasked with implementing activities, reports, providing evidence, guidelines and information on good practices demonstrated by the livestock sector. This paper outlines the activities of the network AN2 “Restoring Value to Grassland”, the purpose of which is to “maintain, restore and enhance environmental and economic value of grasslands, while promoting their social and cultural functions globally”. Since 2014, AN2 workshops have been held annually with scientists and stakeholders from rangeland/grassland biomes in Latin America (Brazil, Uruguay, Argentina, Chile), the Mediterranean (France, North Africa), Sub-Saharan Africa, Highland and Continental Plateaux (Tibetan Plateau/Mongolia/Atlas in Morocco), the mountainous regions of France, New Zealand and Vietnam, and the prairie area of Canada. A data base of 40 global grassland cases and a range of preferred practices have been compiled for these areas. A methodological framework is now available for assessing the contribution of grassland systems to multiple functions, along with the development of associated indicators that are aligned with the sustainable development goals (SDGs) - social, local development, production, economic and environmental. The framework has been built and tested using the global grassland cases. We present the results from three cases from Brazil, Vietnam and Argentina

Herbage Mineral Nutrition Indexed as Tools for Rapid Mineral Status Diagnosis in Tropical Pastures

The animal production sector in the tropics is increasingly becoming challenged with the limited availability of pastures. There is need therefore to explore other options to suppliment the available pastures. The objectives of this study therefore was to understand how herbage mineral dilution indices used in developed countries as tools for controlled fertilisation, could be adapted in a tropical environment where high seasonal variations with regard to availability occur in pastures. A 3-year study was carried out in La Réunion Island, Indian Ocean. Forty nine farms, with swards made of either temperate or tropical grasses, grazed or mowed, were visited between four and five times a year. Dry biomass and dry matter contents were reported at each sample collection; whereas mineral indices were calculated from chemical analysis with a view to generate relevant fertilisation recommendations. Although the dry matter ( DM) values of less than 20% indicated a better stage of exploitation for the grasses, the data consistently indicate a decrease in the seasonal differences of dry biomass for grazed species. The use of indices, which combine both plant mineral status and pasture biomass, appeared relevant indicators for farmers and for pasture experts in tropical countries, and can be predicted through near infrared spectroscopy with an acceptable precision (R2 = 0.80, 0.60 and 0.91, for nitrogen , phosphorous and potassium, respectively). With reduced cost of pasture feed analysis using the NIRS, farmers can be able to make informed decisions based on scientific data. Fertilisation is one of the potential options to improve pasture management as indicated by findings of this study. This is useful evidence-based information that could be incorporated in extension packages and resource materials for dissemination and subsequent adoption by livestock farming communities to improve produtivity.Le secteur de production animal sous les tropiques fait de plus en plus face au défi de la disponibilité limitée de pâturages. Il y a le besoin donc d'explorer d'autres options pouvant suppléé les pâtures disponibles. Les objectifs de cette étude étaient donc de comprendre comment index de dilution minéraux de l'herbage utilisé dans les pays en voie de développement comme outil de fertilisation contrôlé, pourrait être adapté dans un environnement tropical où une variation saisonnière élevée en ce qui concerne la disponibilité des pâturages existe. Une étude de 3 années a été exécutée dans L'Ile de la Réunion dans l'Océan indien. Quarante neuf fermes, avec swards fait d'herbes modérées ou tropicales, broutées ou fauché, ont été visitées quatre à cinq fois par an. La biomasse séchée et le contenu de la matière ont été rapportés à chaque collection d'échantillon ; tandis que les index minéraux ont été calculés à partir de l'analyse chimique avec une vue pour produire les recommandations de fertilisation pertinentes. Bien que la matière sèche (DM) de moins que 20% a indiqué une meilleure étape d'exploitation pour les herbes, les données indiquent régulièrement une diminution dans les différences saisonnières de biomasse sèche pour l'espèce broutée. L'usage des ‘indices, qui combinent à la fois le statut de la plante et la biomasse de pâturage, apparaît comme indicateurs pertinents pour les fermiers et pour les experts de pâturages dans les pays tropicaux, et peut être prédit par la spectroscopie infrarouge avec une précision acceptable (R2 = 0,80, 0,60 et 0,91, pour l'azote, phosphore et de potassium, respectivement). Avec le coût réduit de pâture nourrit l'analyse utilisant le NIRS, les fermiers peuvent pouvoir faire des décisions informées sur basé des données scientifiques. La fertilisation est une des options potentielles pour améliorer la direction de pâturages comme indiqués par les conclusions de cette étude. Cette information est beaucoup plus utile et peut être incorporée dans les packets d'extension et les matériels -ressource de diffusion et l'adoption subséquente de la communauté d'agriculture pour améliorer productivité des bétails

Grazing systems and the control of vegetation dynamics in Reunion island (Indian Ocean)

International audienc

La flore adventice des principales cultures en Guyane française

International audienceBased on 9 preliminary studies, we have obtained a synoptic view of the weed flora of the main cropping systems in French Guyana (food crops, market gardening, arboriculture, pasture, irrigated rice). The overall flora is rich in 334 species, but at the level of each crop, the floristic diversity is fairly similar, with almost 100 species. Twenty or so of these appear to be major species in different crops, while 30 appear to be specific to a particular agricultural context. Euphorbia heterophylla is a major species in food crops, market gardening and arboriculture, Cyperus aromaticus is common to market gardening, arboriculture and pastures, while Ludwigia spp. are found in market gardening, rice growing and pastures. Asystasia gangetica, Digitaria horizontalis, Cyanthillium cinereum and Paspalum conjugatum are major species in market gardening and arboriculture, while Fimbristylis littoralis, Eleocharis filiculmis and Fuirena umbellata are major species in pasture and rice growing. Some species are indicators of soil moisture.A partir de 9 études préalables, nous avons obtenu une vision synoptique de la flore adventice des principaux systèmes de culture de Guyane Française (vivrier, maraîchage, arboriculture, pâturage, riz irrigué). La flore globale est riche de 334 espèces, mais au niveau de chaque culture, la diversité floristique est assez semblable avec près de 100 espèces. Une vingtaine d'entre elles apparaissent majeures dans différentes cultures, tandis que 30 semblent spécifiques à un contexte agricole particulier. Euphorbia heterophylla est majeure en vivrier, maraîchage et arboriculture, Cyperus aromaticus est commune au maraîchage, à l'arboriculture et aux pâturages, tandis que les Ludwigia spp. se retrouvent en maraîchage, riziculture et pâturages. Spermacoce verticillata et Mimosa pudica sont majeures en pâturages et en arboriculture, Asystasia gangetica, Digitaria horizontalis, Cyanthillium cinereum, Paspalum conjugatum sont majeures en maraîchage et arboriculture tandis que Fimbristylis littoralis, Eleocharis filiculmis, et Fuirena umbellata sont majeures en pâturage et riziculture. Certaines espèces sont des indicateurs notamment de l'humidité du sol. Mots-clés : flore adventice, Guyane Française, systèmes de culture, diversité, indicateur écologique