Soil Science Commons^™

Effects Of Climate Change On Grassland Production In Switzerland, J Fuhrer, M Riedo

IGC Proceedings (1997-2023)

A mechanistic model for productive grassland was used to simulate annual dry matter yield in relation to fluxes of C, N, and water, and to test the sensitivity to climate change and to elevated [CO2] (2xCO2). Local weather scenarios were derived from the results of two General Circulation Models (GCM) by statistical down-scaling. Annual yield increased by a maximum of 10% without 2xCO2 effects, by 1-16% in response to 2xCO2, and by 6-24% with the combination of climate change and 2xCO2. Decreased evapotranspiration and increased water use efficiency in response to 2xCO2 were partially offset by climate change. The simulations …

Water Use Efficiency In Chilean And Argentine Humid Temperate Grass-Legume Pastures, H G. Landi, M H. Wade, V Garcia De Cortazar, D E. Dalla Valle

IGC Proceedings (1997-2023)

At two sites in Argentina and Chile five levels of water input were applied to four sown pastures of varying ages during spring and summer. The pastures consisted principally of C3 grasses and legumes, some of which were sown such as Lolium perenne, Trifolium repens, Dactylis glomerata. Dry matter (DM) production was measured and related to the estimated total evapotranspiration (ET): responses were both highly linear. Both responses to ET and absolute yields were higher at the Argentinian than at the Chilean site: respectively 10.7 and 15.2 kg DM/mm water evapotranspired. Nevertheless the calculated indices of sensitivity (Ky) of Doorenbos …

Mechanistic Modelling Of Grassland Energy Balance, G D. Buchan, B Main, B A. Mckenzie

IGC Proceedings (1997-2023)

No abstract provided.

Palatability Of Alfalfa (Medicago Sativa L.) And Orchard Grass (Dactylis Glomerata L.) Silages, R. D. Améndola-Massiotti, J. A. Burgueño, M. Concepción, L. Cruz

IGC Proceedings (1997-2023)

The objective was to compare palatability with different methodologies for characterizing silages at Chapingo Autonomous University, México. Eight silages were used resulting from an experiment which evaluated effects of cutting time (08:00 and 14:00), time of wilting (0, 1 and 2 h) and use of lactic bacteria inoculant on properties of alfalfa (Medicago sativa L.) and orchard grass (Dactylis glomerata L.) silages. Organoleptic properties (odor, color, texture, moisture) were assessed by trained observers, using as categories: excellent, good, fair and poor. Dry matter content, CO₂ rate of production and pH were also measured. For the evaluation of …

Evapotranspiration Of Rewetted And Drained Fen Soils With Grass – Long Term Lysimeter Studies, M. Pesch, J. Hoysagk, F. Eulenstein, A. Behrendt

IGC Proceedings (1997-2023)

In the context of reducing greenhouse gas (GHG) emissions to combat climate change, rewetting of peatlands is of particular importance. High groundwater levels covering organic matter in the soil prevent its oxidation to CO₂. The amount of water needed to allow the rewetting of peatlands can be determined in lysimeter studies.

The evapotranspiration in fens depends essentially on the groundwater table, the vegetation (transpirational active biomass) and the saturation deficit of the atmosphere. After rewetting, these factors can lead to an evapotranspiration of 1000 l m^-2 a^-1 and even 2000 l m^-2 a^-1 in …

Effect Of Timing And Intensity Of Drought On Perennial Ryegrass Seed Yield, R. J. Martin, R. N. Gillespie, S. Maley

IGC Proceedings (1997-2023)

Perennial ryegrass seed worth about $50 million is produced annually in Canterbury, New Zealand (Rowarth 1998). Ryegrass seed production in New Zealand is often affected by drought, reducing both seed number and seed size (Rolston et al., 1994). Irrigation management recommendations are not currently available for farmers growing ryegrass seed crops. To quantify the effect of water stress on perennial ryegrass seed yield, we carried out an experiment in a rainshelter where rainfall was excluded from experimental plots otherwise exposed to normal weather (Martin et al., 1990).