Magnitude and farm-economic value of grain legume pre-crop benefits in Europe: A review

Abstract

a b s t r a c tGrain legume production offers multiple environmental benefits and can enhance sustainability of European farming, but their production area is declining constantly. Grain legume competitiveness is frequently constrained by lower gross margins compared to agronomically suitable cropping alternatives, but it can be improved by appreciating their ability to increase yield of subsequent crop(s) and, potentially, to reduce input requirements (fertiliser, biocide, tillage). Information on the magnitude of grain legume pre-crop effects is diverse and has not been synthesised for European agriculture. This paper reviews research on pre-crop benefits to yield and input requirements of subsequent crops, and the farm-economic profitability of grain legumes in European cropping systems. This includes an analysis of the magnitude of pre-crop benefits to cereal yields measured in 29 experiments in Europe; and 19 studies on grain legume gross margins ranging from crop to cropping system level are assessed. In the available studies, yield benefits of legumes to subsequent crops are highest under low nitrogen fertilisation to subsequent crops and fertilisation can be reduced by 60 kg N ha −1 on average under maintenance of acceptable yields. With the aim at maximising yield potential, nitrogen fertilisation following grain legumes can be reduced by 23-31 kg ha −1 , and cereal yields are mostly 0.5-1.6 Mg ha −1 higher than after cereal pre-crops. With adequate estimates of pre-crop benefits, gross margins of full crop rotations can better assess grain legume competitiveness. In the studies reviewed, 35 of 53 modelled crop rotations with grain legumes were competitive with comparable non-legume rotations. Grain legume rotations were more competitive under conservation tillage systems if gross margin calculations accounted for cost savings arising from adjusted machinery requirements. In conclusion, grain legume pre-crop value is a crucial component of their farm-economic profitability in European cropping systems, but further experimental research is required to ascertain its magnitude. Expanding profitability measures to consider pre-crop effects substantially increases the number of situations where grain legumes can compete with cereals, and has a small positive effect on their competitiveness with alternative break crops. Besides a better consideration of the pre-crop value, further genetic and agronomic improvement in legume cropping, supportive market development, and policy support are required if Europe is to utilise environmental benefits of legumes and increase the sustainability of its farming.

Grain legume decline and potential recovery in European agriculture: a review

“…Gross margin calculations are not, however, able to take into account the non-market outputs, the long-term economic impacts or possible savings of labour and machinery use associated with grain legumes (Weitbrecht and Pahl 2000). Preissel et al (2015) showed that the consideration of precrop effects substantially increases the number of situations where grain legumes can compete with cereals. It also has a small positive effect on their competitiveness compared to alternative break crops.…”

“…It is not considered in standard gross margin methods and is therefore not used explicitly to inform farmers' decisions made using gross margins. In reality, farmers do not always change their fertilizer application rates in crops following legumes (Preissel et al 2015), although fertilizer recommendations do take this into account in some countries (see for example Defra 2010).…”

The after-effect of chosen Fabaceae forecrops on the yield of grain and protein in winter triticale (Triticosecale sp. Wittmack ex A. Camus 1927) fertilized with mineral nitrogen

“…significantly by 840 kg/ha higher (16.1%) than after spring barley (5.21 t/ha). A significant increase in the grain yield in cereals cultivated after leguminous forecrops was also observed by Gan et al (2015) by 0.80 t/ha, Buraczyńska and Ceglarek (2009) by 1.1 t/ha and Preissel et al (2015) by 1.5-1.6 t/ha. It should be emphasized that along with deterioration in humidity conditions in the growing seasons, especially 2015, this difference at level 0 N was up to 1.88-1.93 t/ha (by 43.5% and 54.9%), which confirms a better use of water by successively grown plants after leguminous forecrops, than after cereals (Evans et al 2001, Siddique et al 2012, Espinoza et al 2015, Gan et al 2015.…”

“…Their main advantage is fixing nitrogen (N) in the soil and not depleting its resources for successively grown plants, as well as interrupting the life cycle of agents of many diseases, especially in cereals, owing to a wide ratio of carbon (C) to N of organic matter from the post-harvest residues left after harvest. Fabaceae plants root deeply, contributing to the cycle of nutrients and better use of water by successively grown plants (Evans et al 2001, Siddique et al 2012, Espinoza et al 2015, Gan et al 2015, and decreasing their dependence of yielding on inorganic N (Williams et al 2014), especially under conditions of reduced mineral N fertilization (Reckling et al 2014, Preissel et al 2015. Most of N fixed by leguminous plants is removed with yield (Hauggaard-Nielsen et al 2009, however the remaining part becomes available for the successively grown plants (Armstrong et al 1997, Evans et al 2001, Wysokinski et al 2014, owing to which protein yield in grain of successively grown cereal plants may also be significantly higher (Gan et al 2015).…”

Managing soil functions for a sustainable bioeconomy—Assessment framework and state of the art

“…Leakage, cascade, and rebound effects should be considered (Lambin & Meyfroidt, 2011). The use of multiyear averages and considering production over several years is necessary to account for interannual yield variability and crop rotation effects (Preissel, Reckling, Schläfke, & Zander, 2015;Zhang et al, 2017). (Pascual, Villar, & Rufat, 2016;Wei et al, 2016;Zhao et al, 2010), benefit-cost ratio (Alam et al, 2017;Moreau et al, 2012;Rehman, Farrukh In most cases, increased efficiency aligns with targets set by society or policy targets (e.g., European Commission, 2011; General Assembly, 2015).…”