Effect of sowing rate and date on establishment and growth of &lt;i&gt;Trichloris crinita&lt;/i&gt;, a native American pasture grass from arid environments, in the Arid Chaco of Argentina

Deolindo L.E Domínguez,Pablo F Cavagnaro,Pedro R Namur

doi:10.17138/tgft(9)268-279

Abstract

In arid regions, revegetation with locally adapted native species can improve forage production and help ameliorate soil degradation. We investigated the effects of 3 sowing dates and 3 sowing rates of Trichloris crinita cv. Chamical-INTA, a perennial forage grass native to arid and semi-arid regions, on pasture establishment parameters in the Argentinian Arid Chaco phytogeographical region. Sowing date significantly influenced plant density and soil coverage at the end of the growing season, with the latest sowing date increasing mean plant density and soil coverage by 42‒66% and 16‒38%, respectively, relative to the 1st and 2nd dates. Conversely, the later sowing dates (2nd and 3rd dates) exhibited significantly lower mean values for all plant growth-related traits, i.e. tillers per plant, plant height and percentage of flowering plants. Sowing rate had a strong effect on plant density at the end of the growing season but not on plant growth parameters. Under the conditions of this study, using intermediate sowing densities (7.5 kg seed/ha) and sowing early in the season, when temperatures were still mild, delivered the best results in terms of pasture density and establishment efficacy. Early sowing resulted in a greater percentage of flowering plants and seed set prior to the first winter frosts, which should ensure ongoing establishment of plants in the next wet season. Longer-term studies to examine the survival of plants and possible increase in plant density over time are necessary to determine if this procedure has sustainable benefits for pastures in the area.

Highlights

Drylands, i.e. arid, semi-arid and dry subhumid regions combined, cover nearly 41% of the Earth’s land surface and are home to more than 38% of the total global population (Global Land Project 2005; Millennium Ecosystem Assessment 2005)
We investigated the effects of 3 sowing dates and 3 sowing rates of Trichloris crinita cv
After the non-vegetative winter period, and re-sprouting of the plants in spring, we evaluated plant density, considering only those plants that were visually sprouted and had resumed their vegetative growth; these densities were similar to those recorded at the end of the previous season

Summary

Introduction

I.e. arid, semi-arid and dry subhumid regions combined, cover nearly 41% of the Earth’s land surface and are home to more than 38% of the total global population (Global Land Project 2005; Millennium Ecosystem Assessment 2005). Severe land degradation is present on 10‒20% of these lands, affecting ~250 million people, mainly in developing countries (Millennium Ecosystem Assessment 2005), and current expectations are that these estimates will increase over time due to climate change and population growth. In arid and semi-arid regions, land desertification, characterized by low fertility and organic matter concentration in the soil, is widespread, and this situation is often aggravated by overgrazing by domesticated animals (Papanastasis 2009). Loss of perennial grasses in rangelands, often accompanied by severe soil erosion and salinity, is a frequent component of desertification processes in arid regions (Waters and Shaw 2003). Selection of drought-tolerant species, with adequate seed available, and the utilization of appropriate and sustainable management practices, especially with regard to pasture establishment, are critical for a successful revegetation program (Quiroga et al 2013)

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Conclusion