Tillage Systems in the Establishment of Pastures in Argentinian Subhumid Area

The effect of three tillage systems on the number of plants produced and forage production of a pasture the first year of establishment was assessed in this experiment. The components of the pasture were alfalfa (Medicago sativa L.), tall fescue (Festuca arundinacea Shreb), orchard grass (Dactilys glomerata L), and prairie grass (Bromus unioloides). Treatments were three tillage systems: conventional tillage (CT), reduced tillage (RT), and direct sowing (DS). Sowing was performed with (NI) and without fertilizers (N0) in each treatment. A split-plot experimental design with two repetitions was used, with tillage being the main factor and the fertilization levels the secondary one. Results were subjected to ANOVA while means were compared by the Duncan Test Counts. These were conducted 90 days after sowing to determine the number of emerged alfalfa and grass seedlings. In November, before starting direct grazing, hand cut samples were taken to determine total biomass and also biomass production of each component of the pasture. Total stand plant and grass stand, was significantly affected (P \u3c 0.05) by the tillage factor. Forage production of both alfalfa and grass, and total production was higher with conventional tillage (CT) and differed significantly (P \u3c 0.05) from direct sowing (DS). The fertilizing effect and its interaction with the tillage factor was not statistically significant (P \u3c 0.05) for any of the components measured. Results indicate that direct sowing seems to condition grass plant stand and forage production of each of the pasture components in the year of establishment

Effects of Tree and Tillage Systems on the Productivity of the Herbaceous Stratum in Silvopastoral Systems in the Southwest of Córdoba, Argentina

In the southwest of Córdoba, Argentina, there are lands with severe water erosion, due to the interaction of rolling pampas, high intensity precipitation, loam soil, and farming systems based on annual crops (Cantero et al., 1998). In an attempt to mitigate the erosive processes, a silvopastoral system was established in which winter forage was combined with trees. To improve the physical condition of the soil, two tillage systems were implemented. The objective of this paper was to determine the effect of trees and tillage systems on the production of forage

Biomass Vertical Distribution in a Grazed Grassland Under Monoespecific and Mixed Grazing

Mixed grazing is defined as the use of the same forage resource for more than one herbivore species. It has been shown that different herbivore species have specific grazing modalities (Black and Kenney, 1984), which may differentially modify the structure of the pasture. The aim of this study was to evaluate the biomass vertical distribution in a sward with mixed grazing

Production mechanisms and single-spin asymmetry for kaons in high energy hadron-hadron collisions

Direct consequences on kaon production of the picture proposed in a recent Letter and subsequent publications are discussed. Further evidence supporting the proposed picture is obtained. Comparison with the data for the inclusive cross sections in unpolarized reactions is made. Quantitative results for the left-right asymmetry in single-spin processes are presented.Comment: 10 pages, 2 Postscript figure

Hyperon polarization and single spin left-right asymmetry in inclusive production processes at high energies

It is shown that the polarization of hyperons observed in high energy collisions using unpolarized hadron beams and unpolarized nucleon or nuclear targets is closely related to the left-right asymmetries observed in single spin inclusive hadron production processes. The relationship is most obvious for the production of the hyperons which have only one common valence quark with the projectile. Examples of this kind are given. Further implications of the existence of large polarization for hyperon which has two valence quarks in common with the projectile and their consequences are discussed. A comparison with the available data is made. Further tests are suggested.Comment: REVTeX, 12 pages, 2 figures embedde