Tag Archives: defoliation

5-14 R. Aavola and M. Kärner
Nitrogen uptake at various fertilization levels and cutting frequencies of Lolium species
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Nitrogen uptake at various fertilization levels and cutting frequencies of Lolium species

R. Aavola¹ and M. Kärner²

¹Jõgeva Plant Breeding Institute, Aamisepa 1, 48309 Jõgeva, Estonia;e-mail: rene.aavola@jpbi.ee
²Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences,Kreutzwaldi 5, 51014 Tartu, Estonia; e-mail: malle.karner@emu.ee

Abstract:

A field trial was carried out in 1999–2000 to identify optimal combinations of compound fertilizer rates and defoliation frequencies in perennial ryegrass cv. Raidi (diploid) and Raite (tetraploid) and Italian ryegrass cv. Talvike (tetraploid), to enable the nitrogen (N) requirements of dairy cows to be met. The study aimed at estimating the N utilization in the swards subjected to 6 cycles of simulated grazing or cutting 4 times for silage. N application rates were changed from 0–500 kg ha-1 by 100 kg in the former and from 0–400 by 80 kg ha-1 in the latter harvest regime. Increasing the rate of fertilizer increased the N concentrations and yields. Applying N 300 to ryegrasses defoliated at tillering to stem elongation stage allowed assuring minimum N content in the forage dry matter (2.2%) while at N 500 the upper level (2.7%) was exceeded. The ryegrass plants took up less N than was applied with the compound fertilizer. Increasing the defoliation frequency of grass had a positive effect on N content of the forage, but had inconsistent or no effect on improving N uptake from fertilizer and soil. Perennial ryegrass cultivars were more efficient than Italian ryegrass in taking up N from the soil and fertilizer at simulated grazing. Cutting 4 times a year at moderate to high fertilizer rate applications did not reveal a distinct superiority in N absorption of a particular cultivar, but Italian ryegrass had the best N uptake potential from N deficient soil.

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125–138 M. Duru, J. Tallowin and P. Cruz
Functional diversity in low-input grassland farming systems: characterisation, effect and management
Abstract |
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Functional diversity in low-input grassland farming systems: characterisation, effect and management

M. Duru¹, J. Tallowin² and P. Cruz¹

¹UMR ARCHE, Chemin de Borde Rouge, BP52627, 31326 Castanet Tolosan, France
²Institute of Grassland and Environmental Research, North Wyke, Okehampton, Devon EX20 2SB, UK

Abstract:

High biodiversity in grasslands is widely perceived to have a major role in maintaining or enhancing the amenity and cultural value of landscapes in Europe. In this paper, we focus mainly at community level, evaluating factors that appear to influence biodiversity at farm and landscape levels. In order to establish generic principles we examine the maintenance of biodiversity in terms of maintaining or enhancing functional diversity (FD). We define plant functional types (PFTs), groups of species having the same function and/or the same effect in the grassland ecosystem, species identified on the basis of plant traits. These traits reflect ecological responses to nutrient input and/or defoliation frequency, and they can also have an effect on ecosystem properties. We reviewed the literature, examining the relationship between several leaf and plant traits and principal ecological factors and, in turn, how these traits could influence the feed value of the grassland vegetation for herbivores. FD was determining as the range of relevant PFTs at community, farm and landscape levels. We propose a practical method of assessing agronomic value of semi-natural grasslands based on the determination of dominant PFTs by measuring traits in situ, or through using a trait database coupled to species abundance records. We then assess the relevance of the method for semi-natural grasslands subjected to several management practices.

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75–83 T. Lille, K. Karp and R. Värnik
Profitability of different technologies of strawberry cultivation
Abstract |
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Profitability of different technologies of strawberry cultivation

T. Lille¹, K. Karp¹ and R. Värnik²

¹Institute of Horticulture, Estonian Agricultural University, Kreutzwaldi 64, 51014 Tartu, Estonia; e-mail: tiilille@eau.ee; kkarp@eau.ee
²Faculty of Economics and Social Sciences, Estonian Agricultural University, Kreutzwaldi 64, 51014 Tartu, Estonia; e-mail: vrando@eau.ee

Abstract:

The experiments with strawberries were carried out in 1999–2001. There were two cultivation types in the experiment: plastic mulch and straw mulch with burning after harvesting. The present research investigated the influence of mulches and cultivars on strawberry yield and profit. Straw mulch suits for ‘Jonsok’ and ‘Bounty’ because it increases yields. In places, where late-spring frost damages are usual, the growing of early cultivars with straw mulch would be practical. Plastic mulch suits better for cultivars susceptible to grey mould (‘Senga Sengana’). It is useful to grow different cultivars because their  yields are different according to years. The yield of the plant depends on the cultivar and on the cultivation technology. In year 2000 ‘Jonsok’ grown with straw was more productive and profitable than other cultivars. In 2001 ‘Senga Sengana’ grown with straw was the most productive and more profitable than ‘Jonsok’ and ‘Bounty’. The burning of leaves flights pests and weeds and farmers can save on chemicals. Using straw mulch is more perspective for getting higher yields and profit.

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