Legacy effects of crop sequencing on biomass and their variability on farmers' fields in Finland are shaped by weather, farm conditions and rationales for land use

Abstract

CONTEXTThe legacy effect of a previous crop on a subsequent crop in rotation is a valuable and often underutilized ecosystem service which can provide benefits when designing cropping systems, especially in the case of cereal-based land use. OBJECTIVETo support future diversification of crop sequencing in Finland, this study was carried out with the aims to identify the variation in the pre-crop values of relevant crop combinations in farmers' fields in Finland, depending on the weather and farm conditions. METHODSWe used a method developed to estimate on-farm realized pre-crop value from Sentinel − 2 images available annually for 120,174–711,828 field parcels in Finland during 2016–2020 (the total number of observations was >1,818,000). RESULTS AND CONCLUSIONSBoth the weather and farming conditions explained the variation in the pre-crop values, which might range from positive to negative. For example, a higher mean temperature and fewer rainy days during the growing season of a previous crop often reduced the legacy effects of crop sequencing, however, this was dependent on the crop choices. A higher number of rainy days and elevated temperatures during the subsequent crop's season often increased the pre-crop value, while prolonged droughts in either of the growing seasons tended to reduce these. The farmers' current land use did not support the realization of pre-crop value – especially in the case of potential benefits provided by grasslands for croplands. SIGNIFICANCEThis study highlights the challenges that weather variation and complexity of the production systems may cause for a farmer when aiming to identify the impacts of crop sequencing on yields, ecosystem services, and farm economy. Hence, there is an evident need to develop a decision support system that recognizes regional farming systems, available crop choices, crop management, weather conditions, and the farmers' rationale concerning decision making.