The diversity and species richness of a landscape is not just a value in itself, but it also provides direct economic benefit for farmers.

At first, it might seem that leaving a buffer strip between crop fields doesn’t have a direct effect on the crops. However, research has shown that the wildlife and vegetation of these buffer strips can migrate to the fields. According to an outdated belief, the main species migrating to fields are weeds and pests. This, in fact, is not true. In fact, most insects who migrate to crop fields help to pollinate crops and destroy vermin. Diverse vegetation around the field supports the life of these insects.

Field margins provide (winter) shelter, additional food, breeding grounds and habitats for many pest-killing predatory arthropods, such as parasitoids, ground and rove beetles, arachnids and natural pollinators, such as solitary bees and bumblebees.
 

Pest management

Crops growing on large monoculture fields are suitable for very few insect species. We call these insects ‘pests’ since they compete with us over food. By planting monoculture fields, we are providing pests with an abundant food supply and a great breeding ground. The breeding of pests can only be controlled by their natural enemies, predatory insects (such as parasitoids).

A comprehensive study that included data from Europe (including Estonia), North America and New Zealand revealed that field margins and buffer strips increased the level of pest control in the field by an average of 16% while the number of pests remained the same. Evidence also shows that both the abundance and the diversity of natural enemies and pollinator species are crucial for pest control and increase in yield.

Landscape elements with natural perennial vegetation can only have an effect on the number of predatory arthropods if there are enough high-quality elements. For instance, it has been discovered that ground beetles only reach the crop fields if the field margins are at least four metres wide.

Pollination

Another vital natural benefit is pollination, which has begun to decrease due to monocultural landscapes. Pollinators produce over a third of crop yield.

Pollinators are dependent on landscape elements that have natural perennial vegetation since they provide food, shelter and (winter) habitats. It is important for natural pollinators that there are plants blooming throughout the whole vegetation period. However, in crop fields the flowering period of crops lasts only a short time in summer. About 75% of solitary bee species and most of the bumblebee species in Estonia nest in the soil. In order to do that, they need an area where the soil is not disturbed by ploughing or agricultural machinery and the use of agrochemicals is minimal.

The species richness of vegetation and the age of the landscape element is important for pollinators: the more diverse and the older the field margin is, the more it supports pollinators and the more it contributes to the pollination of the adjacent field. Studies have shown that having the right amount of insect pollinators on a rape field increases harvest by 20-40%, increases oil content and helps the crops ripen more evenly. This reveals that by improving the living conditions of pollinators on agricultural landscapes, we can improve the quality and quantity of the harvest.

In order to ensure pest control and pollination on fields, high-quality landscape elements must make up at least 25% of the entire landscape. Therefore, let’s make monocultural agricultural landscapes more diverse – it’s a win-win situation for producers, consumers, farm tourists and nature itself.
 

See the full article in the March 2021 issue of Eesti Loodus (Estonian Nature), pp. 32-34

Author: Eve Veromann, Professor of the Chair of Plant Health at the Estonian University of Life Sciences

Editor: Kaisa Viira

Last modified: 21.04.2022