Summer 2002

Crop and estate management

It has been a go-stop-go harvest across most of southern Britain this year and here was no exception. A hot period in July got our rape harvest off to a flying start and some of our wheat was harvested before the rain came down in August. Then there was a two week gap when one field stood part harvested. The sun finally shone again and the wheat harvest was finished off.

Our wheat and rape yields are up this year and so we expect to make a modest profit despite the low prices paid for some wheat. The rape yield overall was 3.5t/ha and it was almost 4t/ha on most fields. The average was brought down by one field that woodpigeons had grazed heavily over the winter.

The heavier yielding variety of wheat that we grow (Claire) achieved just over 10 t/ha while the wheat producing a sample of milling quality (Soissons) yielded lower as expected. This latter variety has been sold recently for £70/t when the price for lower quality feed wheat is being quoted at £55/t.

Most stubbles were cultivated rapidly after harvest with the aim of controlling many weeds before the next crop is planted. The weeds germinate rapidly in the seed bed created for them and then are sprayed off with a very short-lived herbicide. The exceptions to this are the fields that are set-aside and the field edge strips where we have been assessing weed populations in relation to herbicide inputs. These areas have been left as stubble and we will be looking to see how many birds make use of the localised rich source of seeds.

The oilseed rape was drilled in late August and it is planned to drill the wheat in early September and early October. The later drilled fields, the second year of wheat in the rotation, will contain a continuation of our trial on exploring how to increase the nesting productivity of our skylarks. We will be swopping the position of the undrilled patches and the wide spaced rows.

Using the same fields means that we work within the same area that is attractive to skylarks. By swapping the treatments we can discover if the skylarks are responding to the specific way that the crop was sown rather than the general attractiveness of the area.

Birds and biodiversity

From the 24 skylark breeding territories identified this year we were able to locate 45 nesting attempts. The first eggs were laid in late March, a month earlier than last year, and the last young fledged in early August. This early start was brought on by the fine, dry weather in March and April and these nests were very successful.

For the rest of the season nesting success was variable. Several cold, wet spells caused some nest failures and there was a poor end to the season, probably through a shortage of food. Losses to predators were low.

We found that the skylark territories, as shown by observations of singing birds, were evenly distributed across the wheat fields, roughly in proportion to the area of the crop. The wheat fields with the undrilled patches and the wide spaced rows both held higher densities of skylark nests during the first two months of the breeding season compared to a conventional wheat field. Later in the summer, the density of nests in the field with the undrilled patches was maintained but the density declined in the field with the wide spaced rows.

Unlike many other farms we have studied over the years, the skylark nest density in the conventional wheat did not decline over the breeding season. On average, we found that the skylark nests in the fields with the undrilled patches and the wide spaced rows fledged one more chick than nests in the conventional wheat.

It will take another year, swapping the position of the trials between fields, before we can be sure if we have found a means for arable farmers to reverse the decline in the skylark population.