The effect of non-inversion tillage on farmland birds, soil and surface-active invertebrates and surface seeds

Cunningham, Heidi Margaret (2005). The effect of non-inversion tillage on farmland birds, soil and surface-active invertebrates and surface seeds. PhD thesis The Open University.

DOI: https://doi.org/10.21954/ou.ro.0000e8ce

Abstract

This thesis investigated the effect of non-inversion tillage (NIT) compared to conventional tillage (CT) on farmland birds and their invertebrate and seed food resources. Farmland birds have suffered severe population and range declines over the last few decades. One major reason is the increased intensification of agriculture leading to a decline in the abundance and availability of food over the summer and winter months. Conventional farming systems have traditionally used a mouldboard plough (CT) to invert the soil to prepare the seedbed for crop establishment. Due to economic pressures and increasing interest in environmental and soil protection, approximately 30% of arable crops in the UK are established by NIT methods. Machinery involved in NIT generally involves the use of discs and tines.

Field occupancy by farmland birds was studied on commercial farms over three winters from 2000 to 2003. In addition, the abundance of seeds and earthworms were investigated during the autumn and spring (2001 - 2003) and surface-active arthropods during March and July (2002 - 2003). The study was carried out at fourteen farms in Oxfordshire, Leicestershire and Shropshire. Experimental work examined the effect of two types of NIT and mouldboard ploughing on the movement of weed and crop seeds in the autumn of 2003.

Skylarks, other granivorous passerines and game birds occupied a greater proportion of cereal fields established by non-inversion tillage than conventional mouldboard ploughing.

Tillage was not significant in explaining the variation in the relative abundance of carabid beetles, staphylinid beetles or spiders trapped in March, May or July. A greater relative abundance of beetle larvae were observed in conventionally tilled fields in July in wheat fields preceded by oil seed rape.

Tillage was not significant in explaining the variation in seed or earthworm abundance or weights in the autumn or spring. The cultivation experiment showed few seeds retained at the soil surface after mouldboard ploughing compared to two NIT methods.