A new approach to characterising and predicting crop rotations using national-scale annual crop maps

Cropping decisions affect the nature, timing and intensity of agricultural management strategies. Specific crop rotations are associated with different environmental impacts, which can be beneficial or detrimental. The ability to map, characterise and accurately predict rotations enables targeting of mitigation measures where most needed and forecasting of potential environmental risks. Using six years of the national UKCEH Land Cover® plus: Crops maps (2015–2020), we extracted crop sequences for every agricultural field parcel in Great Britain (GB). Our aims were to first characterise spatial patterns in rotation properties over a national scale based on their length, type and structural diversity values, second, to test an approach to predicting the next crop in a rotation, using transition probability matrices, and third, to test these predictions at a range of spatial scales. Strict cyclical rotations only occupy 16 % of all agricultural land, whereas long-term grassland and complex-rotational agriculture each occupy over 40 %. Our rotation classifications display a variety of distinctive spatial patterns among rotation lengths, types and diversity values. Rotations are mostly 5 years in length, short mixed crops are the most abundant rotation type, and high structural diversity is concentrated in east Scotland. Predictions were most accurate when using the most local spatial approach (spatial scaling), 5-year rotations, and including long-term grassland. The prediction framework we built demonstrates that our crop predictions have an accuracy of 36–89 %, equivalent to classification accuracy of national crop and land cover mapping using earth observation, and we suggest this could be improved with additional contextual data. Our results emphasise that rotation complexity is multi-faceted, yet it can be mapped in different ways and forms the basis for further exploration in and beyond agronomy, ecology, and other disciplines

Practical methods for the control of tor-grass (Brachypodium pinnatum s.l.) and the restoration of calcareous grassland

Calcareous grasslands are sites of high conservation value across Western Europe; however, they are increasingly threatened by the dominance of a native competitive grass, Brachypodium pinnatum, which reduces the diversity of the grassland. Despite this, there is no clear consensus on the most effective method for controlling B. pinnatum and restoring the grassland community. We established two experiments at a calcareous grassland of high nature conservation value in the UK, i) a herbicide spraying experiment with seeding and ii) a seasonal cut-and-graze experiment, to investigate the potential for reducing dense B. pinnatum cover and preventing further expansion of sparse cover, respectively. We examined the effect of different herbicide and cut-and-graze treatments on B. pinnatum cover, and on the species richness and diversity of the grassland over three consecutive years. Herbicide spraying reduced the cover of B. pinnatum, though two spray applications led to a greater reduction longer-term. Species richness and diversity initially declined with the herbicide spray, however this recovered rapidly to levels higher than before spraying commenced. Seeding the spray plots was beneficial for the establishment of Bromopsis erecta and potentially reduced the likelihood of re-colonisation by B. pinnatum and undesirable arable species. The cut-and-graze experiment also showed promising potential in terms of controlling the spread of B. pinnatum. Compared with a single cut in the spring or autumn, cutting and grazing twice, in both spring and autumn was found to reduce the cover of B. pinnatum, whilst also increasing species richness and diversity. Further monitoring is needed to determine the long-term effectiveness of this management treatment