Yield and species density of grasslands during restoration management

Abstract

Abstract. The relation between the dry matter production and species density of 27 grasslands with different fertilization histories in the Netherlands was studied. The range in species density was 12–28 species on 150 m2, the average annual dry matter production in 1983–1985 varied between 3.3 and 12.8 ton /ha. The results show an optimum curve and confirm the hump‐backed model proposed by other researchers for a great variety of vegetation types. It is concluded that a high species density can be expected when the annual dry matter production above a stubble height of 5 cm, is between 4 and 6 ton/ha (ca. 4.6 ‐ 6.0 ton seasonal maximum standing biomass). Species density can be expected to decrease when the dry matter production exceeds values of 6 ‐ 7 ton ha‐1yr‐1 (ca. 6.0 ‐ 6.7 ton seasonal maximum standing biomass). The implications of this relation for grassland restoration, aimed at an increase in species density, are discussed. The results agree with other grassland data based on the seasonal maximum standing biomass. The difference between annual production estimated by harvesting the biomass after mowing at 5 cm above the soil surface (mostly in two cuts), and the maximum seasonal standing biomass must be taken into account. It is proposed to compare data on the basis of the estimation that 62 ± 5% of the annual yield is harvested at the first cut, and that there is a linear relation between the total standing biomass, y (g/m2), and the biomass harvested above a stubble height of 5 cm, x (g/m2) that could be described by the regression line y = 1.10 x + 189.6 (r = 0.89, p < 0.01, n = 34).

Effects of Vegetation Management and Raising the Water Table on Nutrient Dynamics and Vegetation Change in a Wet Grassland

“…In 1987 the dry matter production in the RR treatment was sufficiently low for an increase in species density to be expected (Oomes 1992). However, no such increase occurred.…”

“…These speciesrich grassland communities have become rare because of intensification of agricultural practices (fertilization, frequent cutting and lowering of the groundwater table). The first condition that has to be fulfilled is a reduction of the dry matter production to at least 4-6 tonnes ha-' year-' (Oomes 1992). Nutrient availability can be reduced by stopping the application of fertilizer and by removing nutrients from the system by cutting or sod stripping.…”

“…New species could establish, the dry matter production apparently being already sufficiently low to allow the invasion of new species (Oomes 1992); but the further increase in species density is limited by the small species pool in the surroundings and the short distance of seed dispersal.…”

Utilization of Permanent Grassland for Biogas Production

“…The number of species of plants has very close relationship to production of above-ground biomass (for example Hejcman et al, 2007;Oomes, 1992). On more impoverished localities, a number of low-growing species coexists.…”

Why do we need permanent plots in the study of long‐term vegetation dynamics?

“…The overall rate of succession can be further analysed by calculating the number of species gained and the number of species lost over a specific time span (e.g. Rydin & Borgegård 1988a;Oomes 1992;Tilman 1993). The rate of successional convergency or divergency in species composition can be analysed by comparing the beta diversities in different years (Christensen & Peet 1984;Rydin & Borgegård 1988b).…”