Soil biota in grassland, its ecosystem services and the impact of management

In the search for sustainable grassland systems, self-regulating processes in the soil become increasingly important. Soil biota play an important role in these processes and in the provision of various ecosystem services. For grassland systems important ecosystem services are supply of nutrients, soil structure maintenance and water retention. For developing and optimising sustainable grassland systems, insight is needed into the mechanisms by which soil biota are influenced by management and what it means for the functioning of the soil-plant system. Interactions between soil and plants can be represented by a cyclic conceptual framework including plant/roots, soil biota and soil properties. The challenge for sustainable grassland is to allow this cycle to function optimally with a minimum of external inputs. In these systems the soil food web is probably bacterial-based with a high density of earthworms. The impacts of grassland management on soil biota are discussed on the basis of two cases: use of grass-clover mixtures and a ley-arable crop rotation versus permanent grassland and continuous arable land

Biologische boer als natuurbeheerder

Naast landbouwgronden kent Nederland ook natuurgronden zoals gras- en rietlanden en reservaatakkers. Beheerslanden die regelmatig worden gemaaid vragen extra kosten voor het afvoeren van plantenresten. Samenwerking met boeren is dan interessant. Dit vraagt echter om een goede landelijke regeling waarbij de kosten in redelijkheid worden verdeeldBiologische boeren kunnen hieraan een bijdrage leveren, maar is dit wel interessant en rendabel? Het Louis Bolk Instituut doet onderzoek naar rendabele en werkzame systemen om beheersgronden tot een wederzijdse meerwaarde te brengen voor boeren en natuurorganisaties

Protocol Natuurplan voor biologische landbouwbedrijven.

The Protocol Nature Plan is a step by step approach leading to the design of a Nature Plan for a biological farm. The aim is to increase nature values and ecological relationships on the farm. Research results are translated into easy practical measure

Steps towards food web management on farms

This paper is the report of four years of research on the functional group composition of the animal community in relation to farm and ecological infrastructure (E.I.) management on organic arable farms. The results are mainly based on abundance data of ground dwelling arthropods obtained by pitfall trapping, density data of vegetation dwelling arthropods by vacuum sampling and density data of insectivorous birds by territory mapping. Arthropods were collected in wheat crops (representing the crop area) and on the adjacent canal bank (representing the E.I.); the bird, farm and E.I. variables were measured at the farm level. Study areas included in total 18 farms with varying extents of organic duration, crop rotation intensity, and quantity and quality of E.I.The hypothesis of the research was that the food web structure of an organic arable farm with long organic duration as well as with an improved E.I. ( i.e. enlarged, late mown), would show a higher abundance of meso- and macrofauna of both herbivorous and detritivorous functional groups. These enhanced primary groups were expected to carry a high predator abundance at both secondary ( i.e. invertebrates) as well as tertiary ( i.e. birds) levels. With regard to the crop areas it was found, in contradiction to the hypothesis, that herbivores were most abundant in crop areas of recently converted farms and of organic farms with intensive crop rotation; this herbivore abundance was associated with invertebrate predator abundance and species diversity. In accordance with the hypothesis, some evidence was found for increased detritivore and related epigeic predator abundance related to extensive crop management on the farms of long organic duration. Whilst studying the E.I., an increased abundance of vegetation dwelling predators and also detritivores was found in improved E.I. However K-herbivore numbers did not increase in the improved E.I. when they were compared to the traditionally managed E.I. The summer abundance of epigeic predators was also not related to an improved E.I. Field studies provided some evidence for the dispersal of functional groups, abundant in the E.I., towards the crop area. However, the effects of crop conditions on the arthropod abundance in the crop area were observed to offset the influence of the E.I. Bird studies at the farm level revealed positive correlation between bird functional groups and a combination of crop area and E.I. characteristics. Bird density was found to be positively associated with high arthropod abundance in the E.I. vegetation canopy. Observations also suggested positive correlation to an increased herbivory in the crop area of the long duration organic farms that had an intensive crop rotation.A proposal for a descriptive or topological farm food web is drawn from field observations as well as from references in literature. Predictions are made for four different farm food web structures that express four extremes of two environmental gradients, which correspond to the length of organic duration and the amount/quality of the E.I. With reference to field observations important themes in the food web theory are discussed, including the indirect effects of subsidised detrital food chains on herbivore abundance and consequently on bird abundance, as well as the possible effects of intra guild predation on arthropod functional group composition.The implications of the study are that organic duration and the amount/quality of the E.I. may contribute to improving ecosystem services and to aims based on nature conservation. However an optimisation of the farm food web with regard to ecosystem services may not necessarily improve nature conservation values. It is argued that increased understanding of the farm food web and its management is likely to support the development of multi-species agroecosystems that integrate improved ecosystem services and nature conservation goals.</p

Analysis of the soil food web structure under grass and grassclover

The below ground biodiversity of soil organisms plays an important role in the functioning of the the soil ecosystem, and consequently the above ground plant production. The objective of this study is to investigate the effect of grass or grass-clover in combination with fertilisation on the soil food web structure. In 2003 a fertilisation trial on grass and grassclover was sampled for soil organisms. Data were agglomerated in seven trophic groups, and classified by means of TWINSPAN. TWINSPAN clearly distinguished three main soil food web structures: Type 1: Grass plots with a high biomass of bacteria and fungi; Type 2: Grass-clover plots with a high biomass of earthworms; Type 3: Grass and grass-clover plots, that received relativily high fertilisation, with a high number of nematodes. Results suggest a microbial oriented soil food web for grass and an earthworm orientated soil food web for grass-clover

Ontwikkeling van flora en vegetatie op twee alternatieve melkveebedrijven

In 1993 the vegetation of two dairy farms on sandy soil was analysed: an integrated farm (Tinteler 20 ha) and a biodynamic farm (at Doldersum, 52 ha). Emphasis was put on indicator plants for nutrient level and humidity