Development of the farming system
Farming has been an integral part of the Northmoor Trust since 1991.
Between 1991 and 1996 the land was conventionally cropped and the farm also supported a small sheep flock. In 1997 increasing concerns about the impact of intensive farming on wildlife and the environment led us to convert from a conventional to an integrated approach for farming our arable land. Integrated farming systems aim to work with rather than against natural processes and to minimise inputs of pesticides and fertilisers. By reducing the reliance on chemical inputs there should be both environmental and economic benefits. The development of the new arable system has required us to modify many of our farming methods namely the crop rotation, fertiliser inputs, pesticide inputs and soil cultivations. We have also adopted practices such as conservation headlands to further encourage wildlife on the farm.
Livestock production has been and still is subject to economic pressure and careful consideration was given to the retention of the sheep flock in the system. By creating a more heterogeneous landscape mixed farming systems are seen as being particularly beneficial in maintaining biodiversity on farmland. There are also agronomic advantages associated with mixed farming. For example, undersowing temporary grass leys with clover can increase soil nitrogen levels which can be utilised by the following crop. It was for these reasons that in 1998 we decided to allocate part of the arable land to a mixed system including a sheep flock of 320 breeding ewes.
Crop rotation
A five-year arable rotation has been put in place based on 5 blocks of 20ha. This rotation maximises the area of wheat grown and should also help to reduce disease and weed problems.
| Year | 1 | 2 | 3 | 4 | 5 |
| Crop sequence | Winter wheat | Spring peas | Winter wheat | Winter barley | Winter oilseed rape |
In the UK, high yielding and more profitable winter varieties sown in the autumn have largely replaced spring-sown crops. This has had a disastrous effect on some birds, particuarly over-wintering buntings and finches which feed on stubbles, and skylarks which nest in spring-sown crops. On our farm we have tackled this problem by including a second break-crop of spring peas following a winter wheat crop. This has enabled us to leave stubbles over-winter for farmland birds. Peas are also a leguminous crop and may help reduce inputs of nitrogen.
Fertiliser inputs
The overall increase in fertiliser use and the miss-application of fertiliser have been cited as one of the main causes for rare arable plant decline, a decrease in the biodiversity of flora of field margins and water pollution. It makes good economic sense to reduce the amount of fertiliser applied to a level where it produces optimal economic response. On our farm we take soil samples from fields to measure the amount of soil mineral nitrogen, to enable us to calculate nitrogen applications to target yield. Great care is also taken by our contractors to ensure nitrogen is not applied beyond the crop and timing of application of fertiliser is considered carefully to maximise plant uptake and minimise leaching of nitrate.
Pesticide inputs
Insecticides
Many insecticides kill not only pests such as cereal aphids but also other invertebrates, including predators of aphids and pollinators of crops. On our farm insecticides are only applied when pest numbers reach damaging levels and products are chosen that specifically target the pest concerned. We also rely on natural control of pest species by invertebrate predators such as spiders and ground beetles. These predators have been encouraged on our land via the creation of wildflower and tussocky field margins, and beetle banks.
Herbicides
Clean crops and stubbles are considered important to minimise competition and improve yield. Weed free crops also help to avoid harvesting difficulties, such as increased moisture content and crop contamination. Nationally, herbicide use has increased over the past few decades and has been cited as a cause in the decline of arable plants and their associated invertebrates on farmland.
We aim to reduce herbicide inputs by targeting specific problems in individual fields. Particular care is given to protecting all field margins and hedgerow bases, and populations of rare arable flowers from herbicide drift. Furthermore, conservation headlands and whole field set-aside have been included in our arable rotation to provide areas of unsprayed land for wildlife.
Fungicides
Although fungicides are thought to have little detrimental effect on wildlife and the environment they do represent a cost to the farmer. We are trying to reduce fungicide inputs by selecting varieties of crops with natural resistance to fungal diseases and only applying fungicides when disease reaches a point where it is going to cause economic damage to the crop.
Molluscicides
Slugs can cause considerable damage to crops, occasionally resulting in complete devastation. Molluscicides are the most commonly used form of control but they are also particularly harmful to other forms of farmland wildlife, such as earthworms and small mammals. We are currently investigating more environmentally friendly forms of control on our farm.
Growth regulators
An interaction exists between nitrogen application and the crops ability to resist lodging (falling flat). Higher levels of nitrogen promote growth and yield but also increase the risk of lodging and growth regulators are applied to prevent this. Eliminating the input of growth regulators is a hard case to argue as they are inexpensive and have no known adverse environmental impacts. By selecting stiff straw varieties and insuring nitrogen application is set to target yield we have been able to grow cereal crops without growth regulators.
Soil cultivation
Ploughing is the traditional technique used for preparing seed-beds and controlling weeds but is energy demanding and time consuming making it an expensive form of cultivation. Recent evidence suggests that it is also deleterious to soil inhabiting invertebrates. We are investigating the use of alternative cultivation techniques namely minimal cultivation and direct drilling, that are energy saving and potentially less damaging to soil organisms.
Conservation headlands
Rare arable plant and farmland bird numbers have declined on arable farmland over the same time period that arable farming has become more intensified. Increases in the use of herbicides and fertilisers are thought to be among the main reasons for the loss in rare arable plants, whilst the indirect effect of herbicides on chick food insects is thought to be one of the reasons for declines in farmland birds such as the grey partridge.
The Game Conservancy Trust developed conservation headlands to encourage growth of broadleaved weed species in cereal fields and the invetebrates associated with them. Invertebrates, weeds and their seeds provide a vital food source for farmland birds and small mammals. Furthermore, the headlands provide an important refuge for rare and delclining arable plants. As arable plant seedbanks are usually confined to the outer 4 metres of fields, conservation headlands occupy the area between the crop edge and the first tramline. This area is usually 6 metres wide according to sprayer boom width. The headlands do not receive broadleaf herbicide treatment (although graminicides may be used) and should have no insecticide treatment after the 15th March.
On our farm headlands are placed adjacent to wildflower margins and are also implemented on all first wheat fields. Surveys have been conducted to assess the success of creating conservation headlands on the farm in terms of encouraging the establishment of arable flora.
