Diagnosing Nitrogen, Phosphorous And Potassium Status Of Natural Grassland In The Presence Of Legumes,
2023
INRA, France
Diagnosing Nitrogen, Phosphorous And Potassium Status Of Natural Grassland In The Presence Of Legumes, C. Jouany, P. Cruz, J. P. Theau, M. Duru
IGC Proceedings (1997-2023)
In most temperate areas, sustainable management of grassland ecosystems has to deal with evaluation and management of N, P and K resources. For this purpose, appropriate diagnostic systems are needed in order to manage fertilisation accordingly. The nutrient index method based on nutrient concentrations in plant tissues relative to the degree of growth has been developed; it relies on critical curves which serve for diagnostic: for N, the critical curve gives the optimum N concentration for different levels of biomass accumulation in swards, for P and K optimum concentrations are a linear function of sward N concentration (Duru & Thélier-Huché, …
Fertiliser Responses And Soil Test Calibrations For Grazed Pastures In Australia,
2023
Primary Industries Research Victoria, Australia
Fertiliser Responses And Soil Test Calibrations For Grazed Pastures In Australia, C. J. P. Gourley, A. Melland, K. I. Peverill, P. Strickland, I. Awty, J. M. Scott
IGC Proceedings (1997-2023)
On-farm management of fertiliser is of major economic significance to the Australian grazing industries, based on expenditure on fertiliser and higher farm productivity that fertiliser use supports. However the application of fertiliser has traditionally been an inexact and inefficient process (Peverill et al. 1999) and there is increasing pressure for nutrient losses from agriculture to be minimised. The improved adoption and application of tools like soil testing can make substantial improvements in nutrient use efficiency but interpretation needs to be based on the best available information. This paper reports on the collation of current and historical experimental data relating …
Potential For Forecasting Uk Summer Grass Growth From The North Atlantic Oscillation,
2023
Harper Adams University College, UK
Potential For Forecasting Uk Summer Grass Growth From The North Atlantic Oscillation, P. S. Kettlewell, J. Easey, P. D. Hollins, T. Martyn, D. B. Stephenson
IGC Proceedings (1997-2023)
The North Atlantic Oscillation (NAO) is a large-scale atmospheric circulation pattern which is well-known to influence the UK winter climate (Wilby et al., 1997). Recently, it has been shown that the winter NAO also affects summer rainfall in the UK (Kettlewell et al., 2003). Since water supply is an important limitation to summer grass growth in many parts of the UK, the winter NAO may influence summer growth. The objective of this study was to test the hypothesis that there is a relationship between the winter NAO and summer grass growth using data from reference plots at North …
Modelling Grass Productivity In The Brazilian Amazon,
2023
Universidade de São Paulo, Brazil
Modelling Grass Productivity In The Brazilian Amazon, C. E. P. Cerri, K. Paustian, C. C. Cerri, F. F. C. Mello, M. Bernoux, K. Coleman, E. Milne
IGC Proceedings (1997-2023)
The Amazon Basin covers an area of 7 million km2, and the central part is almost entirely located within Brazilian territory. This region has the highest rates of deforestation in the world, and the total area deforested now exceeds 600,000 km2. Cattle pasture represents the largest single use (about 70%) of this once-forested land in most of the Brazilian Basin, with an estimated area of 20 million hectares. Our main objective was to simulate grass productivity in different forest to pasture chronosequences within the Brazilian Amazon.
Simulation Of Lablab Pastures,
2023
CSIRO Sustainable Ecosystems, Australia
Simulation Of Lablab Pastures, Jacqueline O. Hill, M. J. Robertson, A. M. Whitbread, B. C. Pengelly
IGC Proceedings (1997-2023)
The potential of legume-based pastures to address declining soil nitrogen on marginal cropping soils is increasingly recognised in northern Australia, as such there is a need for cost benefit analysis of pastures and crops in a mixed farming system. In highly variable rainfall environments, biophysical modelling may be the best way of identifying and quantifying interactions with mixed crop-livestock systems on a seasonal basis. This paper describes a case study where both animal productivity and lablab pasture production is simulated. Lablab (Lablab purpureus) is an annual tropical legume widely used as a short-term legume phase in crop-pasture rotations, …
A Herbage Growth Model For Different Types Of Natural Grassland,
2023
Universidade Federal de Santa Maria, Brazil
A Herbage Growth Model For Different Types Of Natural Grassland, J. Viégas, M. Duru, P. Cruz, J. P. Theau, P. Ansquer, C. Ducourtieux
IGC Proceedings (1997-2023)
The aim of this work was to extend existing growth models established for pure stands to a wide range of grassland communities. For this purpose we built a simple growth model, including sub-models for radiation interception and use. Parameters for the effect of nutrient rates (N, P) and defoliation regimes were based on a plant trait database. Senescence and reproductive processes were particularly considered because of their importance in late spring growth. The model makes it possible to simulate the daily biomass production as a function of both environmental factors and the functional type of the dominant species in the …
Variation Of Ldmc And Sla Relationship Between Growth Forms In Natural Grasslands,
2023
Universidade Federal de Santa Maria, Brazil
Variation Of Ldmc And Sla Relationship Between Growth Forms In Natural Grasslands, J. Viégas, P. Cruz, J. P. Theau, C. Jouany, P. Ansquer, R. Al Haj Khaled, O. Therond, M. Duru
IGC Proceedings (1997-2023)
In agro-ecological studies, there is a growing interest in measuring both leaf dry matter content (LDMC) and specific leaf area (SLA). This interest lies on the fact that leaf traits are linked to gradients of environmental factors and ecosystem functions. Working with three contrasting wild species, Garnier et al. (2001) proposed a model linking these two traits. The model shows a relatively simple non linear and negative correlation between LDMC and SLA. Nevertheless, none of the species used to build the model were grasses (GRA) or forb rosettes (ROS = i.e. dicotyledonous with large entire leaves and absence of …
Adapting The Cropgro Model To Predict Growth And Perennial Nature Of Bahiagrass,
2023
University of Florida
Adapting The Cropgro Model To Predict Growth And Perennial Nature Of Bahiagrass, S. J. Rymph, K. J. Boote, J. W. Jones
IGC Proceedings (1997-2023)
The objective of this research was to modify an existing crop growth model for ability to predict growth and composition of bahiagrass (Paspalm notatum Flügge) in response to daily weather and management inputs. The CROPGRO-CSM cropping systems model has a generic, process-oriented structure that allows inclusion of new species and simulating cropping sequences and crop rotations. An early adaptation of CROPGRO-CSM "species files" for bahiagrass over-predicted growth during late fall through early spring, and totally failed in re-growth if all foliage was lost from freeze damage. Revised species parameters and use of "pest damage" offered only a partial solution. …
State And Transition Model Of Lowland Grassland In Flooding Pampa,
2023
Universidad de Buenos Aires, Argentina
State And Transition Model Of Lowland Grassland In Flooding Pampa, E. J. Jacobo, A. M. Rodríguez, V. A. Deregibus
IGC Proceedings (1997-2023)
Rainfall conditions are considered to be a major factor in determining vegetation structure in temperate grasslands with grazing playing a secondary role (Biondini et al., 1998; Sternberg et al., 2000). In order to analyse the relative importance of both factors on the lowland community of the Flooding Pampa we compared the responses of functional groups under both intermittent and continuous grazing regimes over a 3- year period of important inter seasonal rainfall variation. The results are presented in a state and transition model.
The Influence Of Growing Degree Days On Robinia Pseudoacacia Browse Quality And Productivity In The Southeastern Usa,
2023
North Carolina State University
The Influence Of Growing Degree Days On Robinia Pseudoacacia Browse Quality And Productivity In The Southeastern Usa, L. J. Unruh Snyder, J. Paul Mueller, Jean-Marie Luginbuhl, K. E. Turner, C. Brownie
IGC Proceedings (1997-2023)
The possibility of estimating browse quality and productivity of black locust (BL; Robinia pseudoacacia L.) herbage from accumulated air temperature heat units (growing degree days, GDD) could be a valuable tool for researchers and graziers in efficient allocation of feed resources. Accumulated air temperature heat units (GDD) above a 10° C base have been used to predict several forage quality constituents (Onstad & Fick ,1983).
Modelling Tiller Density Dynamics In A Grass Sward,
2023
University of Miyazaki, Japan
Modelling Tiller Density Dynamics In A Grass Sward, Masahiko Hirata
IGC Proceedings (1997-2023)
Simulation models are useful tools for grassland management. Among many quantitative and qualitative attributes describing vegetation of grasslands, density of plant population is important because of its close relationship with persistence of grasslands (Hirata, 2004), which in turn is crucial for sustainable agricultural production and/or conservation of the environment, wildlife and recreational resource. Although various models have described grassland vegetation, relatively few models have dealt with plant population density. This paper presents a model describing dynamics in tiller population density in a grass sward.
Leaf And Tiller Dynamics In Centipede Grass And Bahia Grass,
2023
University of Miyazaki, Japan
Leaf And Tiller Dynamics In Centipede Grass And Bahia Grass, M. A. Islam, Masahiko Hirata
IGC Proceedings (1997-2023)
Centipede grass (Eremochloa ophiuroides (Munro) Hack.) is a warm-season perennial which has received the attention of farmers and researchers as a new forage resource for sown pastures in the low-altitude regions of south-western Japan where bahia grass (Paspalum notatum Flügge) has been widely used (Islam & Hirata, 2005). Leaf and tiller dynamics provide the basis to explain variation in production and canopy structure of a grass sward (Rhodes & Collins, 1993), and knowledge of the dynamics can be used as a tool for sward management. However, this information is lacking for centipede grass (Islam & Hirata, 2005). The …
Modelling Winter Grass Growth And Senescence,
2023
Teagasc, Ireland
Modelling Winter Grass Growth And Senescence, D. Hennessy, S. Laidlaw, M. O'Donovan, P. French
IGC Proceedings (1997-2023)
In temperate climates, because net grass growth in winter is low, most grass growth models deal with the main growing season (Mar-Oct in the N Hemisphere), with little emphasis on grass growth in winter (Nov-Feb). However, grass tissue turns over continuously (Hennessy et al., 2004) and the fate of herbage entering the winter is important in extended grazing season systems. This study aimed to model winter grass growth for the period 15 Oct 2001 to 28 Jan 2002 for a range of autumn closing dates (1 Sep, 20 Sep and 10 Oct) by modifying an existing model, so that …
Leaf Dry Matter Content Of Native Grassland Species Under Contrasting N And P Supply,
2023
INRA, France
Leaf Dry Matter Content Of Native Grassland Species Under Contrasting N And P Supply, P. Cruz, C. Jouany, Jérome M. Enjalbert, Michael Duru
IGC Proceedings (1997-2023)
The management of native grasslands - herbaceous vegetation with a broad diversity of flora and a large range of uses - must meet the requirements of environmental conservation and improvement of the quality of agricultural production. For this purpose we need tools for diagnosing the state of the vegetation in order to design, evaluate, and apply management practices to attain these objectives. These tools must be simple and quick to use and should not require botanical skills. Leaf dry matter content (LDMC) has been proposed as a good indicator of both fertility gradients and species preference for habitats (Cruz et …
The Use Of Near Infrared Reflectance Spectroscopy (Nirs) To Follow The Leaf/Stem Ratio Of Legumes During Drying,
2023
Walloon Agricultural Research Centre, Belgium
The Use Of Near Infrared Reflectance Spectroscopy (Nirs) To Follow The Leaf/Stem Ratio Of Legumes During Drying, D. Stilmant, Virginie Decruyenaere, C. Clément, P. Dardenne, N. Grogna
IGC Proceedings (1997-2023)
Legume-rich mixed swards allow the production of a high quantity protein-rich forage with low nitrogen input. Nevertheless, during hay or silage making, dry matter losses as high as, 40 and 25 % have been recorded (Ciotti & Cavallero, 1979; Stilmant et al., 2004). These losses have mainly been linked to the high sensitivity to physical loss of legume leaves during drying. The development of a tool to characterise leaf losses or leaf/stem ratio during drying will help us to define the technical approach to reach the best compromise between quality loss reduction and good pre-wilting of legum-rich mixed swards. …
Near Infrared Spectroscopy Of Faeces To Predict Diet Quality In Grazing Animals: Development Of A Portable System,
2023
Texas A&M University
Near Infrared Spectroscopy Of Faeces To Predict Diet Quality In Grazing Animals: Development Of A Portable System, D. R. Tolleson, J. W. Stuth
IGC Proceedings (1997-2023)
Faecal near infrared spectroscopy (FNIRS) has been used to predict dietary crude protein (CP) and digestible organic matter (DOM) in grazing animals (Stuth et al., 2003, Coates 2000). Development of robust FNIRS calibrations can be time consuming and costly, thus hindering the application of FNIRS in developing countries. Delivery of samples to central laboratory facilities is dependant upon adequate transportation infrastructure. A "take the laboratory to the samples" approach is being tested in Mongolia using a portable FNIRS laboratory (Stuth et al,. 2004). The initial step in this process is to duplicate the performance of a static laboratory …
Potentialities Of Near Infrared Spectroscopy To Assess Nitrogen, Phosphorus And Potassium Nutrient Status Of Grasslands In The Reunion Island,
2023
CIRAD, France
Potentialities Of Near Infrared Spectroscopy To Assess Nitrogen, Phosphorus And Potassium Nutrient Status Of Grasslands In The Reunion Island, Philippe Lecomte, Vincent Blanfort, Michael Duru, P. Thomas, P. Grimaud
IGC Proceedings (1997-2023)
Controlled mineral fertilisation practices are an important component for sustainable management of grasslands. The assessment of available nutrients for plants and the general recommendations on the level of phosphorus and potassium to apply to grasslands are classically based on classical soil analysis and average regional levels. For nitrogen, mid or long term recommendations cannot easily be derived solely from soil composition, because it may be rapidly leached from the soil. Recent approaches tended to show that herbage plant N (Lemaire & Gastal, 1997), P, K (Duru & Huché, 1997) mineral analyses associated with actual biomass measurement could be useful for …
The Prediction Of Biological Nitrogen Fixation,
2023
SAC, UK
The Prediction Of Biological Nitrogen Fixation, C. F. E. Topp, C. A. Watson, R. M. Rees, I. Sanders
IGC Proceedings (1997-2023)
In organic farming systems, biological nitrogen (N) fixation is crucial for short-term productivity and long-term sustainability. However, the estimation of biological N fixation is fraught with difficulties, and many equations attempt to estimate the process. As part of an organic research programme, biological N fixation was measured by the 15N dilution technique in the ley phases of 2 experimental organic ley-arable rotations at 2 sites, between 1997 and 2000. Hence, N fixation has been determined on N partitioned to above-ground biomass. The measured values have been compared with N fixation estimates calculated from the equations proposed by Korsaeth & …
Assessment Of The Nitrogen Nutrition Index (Nni) By The Nitrogen Concentration Of The Upper Part Of The Sward,
2023
Catholic University of Louvain, Belgium
Assessment Of The Nitrogen Nutrition Index (Nni) By The Nitrogen Concentration Of The Upper Part Of The Sward, B. Deprez, R. Lambert, A. Peeters
IGC Proceedings (1997-2023)
The Nitrogen Nutrition Index (NNI) is based on the concept of a critical nitrogen concentration, defined as the minimum N concentration in the aerial biomass necessary to obtain maximum yield. Values of Ncrit are high at the start of the growing period and decline during growth, in relation to dry matter accumulation (t DM/ha) according to the equation of Lemaire & Salette (1984): Ncrit(%) = 4.8(DM)-0.32. The NNI is calculated as the ratio of the actual N concentration of the sward to the N concentration required at a similar biomass to sustain non-limiting growth and biomass …
Compilation Of A Database Of Research Information On Legume Based Grazing Systems; A Part Of The Leggraze Research Project,
2023
Institut Universitaire de Technologie, France
Compilation Of A Database Of Research Information On Legume Based Grazing Systems; A Part Of The Leggraze Research Project, J. J. Rochon, G. Molle, A. Hopkins, J. M. Greef
IGC Proceedings (1997-2023)
The establishment of a publicly accessible web-resident database of published and current European research on agronomy, animal production and environmental impact of legume based grazing systems is reported. This database facilitates the sharing of information among the partners of the "Low input animal production based on forage legumes for grazing systems" (Leggraze), a research project funded by the UE (QL K5 CT-2001-02328). It also forms an important tool for transferring the results of the project to the wider research community and to end users in the agricultural sector and to policy makers at national and community level.
