Water productivity of rainfed maize and wheat: A local to global perspective

Water productivity (WP) is a robust benchmark for crop production in relation to available water supply across spatial scales. Quantifying water-limited potential (WPw) and actual on-farm (WPa) WP to estimate WP gaps is an essential first step to identify the most sensitive factors influencing production capacity with limited water supply. This study combines local weather, soil, and agronomic data, and crop modeling in a spatial framework to determine WPw and WPa at local and regional levels for rainfed cropping systems in 17 (maize) and 18 (wheat) major grain-producing countries representing a wide range of cropping systems, from intensive, highyield maize in north America and wheat in west Europe to low-input, low-yield maize systems in sub-Saharan Africa and south Asia. WP was calculated as the quotient of either water-limited yield potential or actual yield, and simulated crop evapotranspiration. Estimated WPw upper limits compared well with maximum WP reported for field-grown crops. However, there was large WPw variation across regions with different climate and soil (CV=29% for maize and 27% for wheat), which cautions against the use of generic WPw benchmarks and highlights the need for region-specific WPw. Differences in simulated evaporative demand, crop evapotranspiration after flowering, soil evaporation, and intensity of water stress around flowering collectively explained two thirds of the variation in WPw. Average WP gaps were 13 (maize) and 10 (wheat) kg ha−1 mm−1, equivalent to about half of their respective WPw. We found that non-water related factors (i.e., management deficiencies, biotic and abiotic stresses, and their interactions) constrained yield more than water supply in ca. half of the regions. These findings highlight the opportunity to produce more food with same amount of water, provided limiting factors other than water supply can be identified and alleviated with improved management practices. Our study provides a consistent protocol for estimating WP at local to regional scale, which can be used to understand WP gaps and their mitigation

Water productivity of rainfed maize and wheat: A local to global perspective

Water productivity (WP) is a robust benchmark for crop production in relation to available water supply across spatial scales. Quantifying water-limited potential (WPw) and actual on-farm (WPa) WP to estimate WP gaps is an essential first step to identify the most sensitive factors influencing production capacity with limited water supply. This study combines local weather, soil, and agronomic data, and crop modeling in a spatial framework to determine WPw and WPa at local and regional levels for rainfed cropping systems in 17 (maize) and 18 (wheat) major grain-producing countries representing a wide range of cropping systems, from intensive, highyield maize in north America and wheat in west Europe to low-input, low-yield maize systems in sub-Saharan Africa and south Asia. WP was calculated as the quotient of either water-limited yield potential or actual yield, and simulated crop evapotranspiration. Estimated WPw upper limits compared well with maximum WP reported for field-grown crops. However, there was large WPw variation across regions with different climate and soil (CV=29% for maize and 27% for wheat), which cautions against the use of generic WPw benchmarks and highlights the need for region-specific WPw. Differences in simulated evaporative demand, crop evapotranspiration after flowering, soil evaporation, and intensity of water stress around flowering collectively explained two thirds of the variation in WPw. Average WP gaps were 13 (maize) and 10 (wheat) kg ha−1 mm−1, equivalent to about half of their respective WPw. We found that non-water related factors (i.e., management deficiencies, biotic and abiotic stresses, and their interactions) constrained yield more than water supply in ca. half of the regions. These findings highlight the opportunity to produce more food with same amount of water, provided limiting factors other than water supply can be identified and alleviated with improved management practices. Our study provides a consistent protocol for estimating WP at local to regional scale, which can be used to understand WP gaps and their mitigation

Variability of European farming systems relying on permanent grasslands across biogeographic regions

The relevance of permanent grasslands (PG) for a large share of European farms is high, and yet understudied. We used single-farm records from the FADN (Farm Accountancy Data Network) database 2017, which included 41,926 farms-with-PG to characterize PG-based farming systems. Each farm was assigned to one class in terms of: (1) main livestock species/category; (2) stocking rate on total farmland; (3) PG share; (4) biogeographic region (BGR). We carried out a Multi Correspondence Analysis (MCA) on the resulting classification, which explained 20% of the variance. The five BGR separated well in the first two MCA dimensions. Alpine farms were predominantly related to beef cattle, with relatively low stocking rates, and intermediate to high PG shares. Atlantic farms also revealed high PG shares, but were linked to higher stocking rates and ‘Mixed bovine’ and ‘Dairy cow’ farming. The dominance of farms without livestock in the Boreal BGR resulted in generally very low stocking rates and showed a limited importance of PG. Continental farms were not clearly related to one specific livestock category or a stocking rate, but consistently showed a share of 10-30% PG per farm. Finally, the Mediterranean BGR separated from the others, being dominated by sheep and goat farming

A management-based typology for European permanent grasslands

European permanent grasslands (PG) vary widely in their delivery of agricultural outputs and other ecosystem services and hence in their challenges and opportunities for sustainable grassland management. To facilitate communication and knowledge transfer, improve inventories, ease mapping and provide a framework for future data collection across the whole range of European PG, we have developed a two-level grassland typology that focuses on PG management (defoliation, fertilisation, renewal) and its determinants (productivity potential, presence of woody plants, additional site attributes affecting management). The typology consists of eight first-level and 18 subordinate second-level classes, based on management intensity, productivity potential, presence of woody plants and grassland renewal intervals. It is applicable both at field and regional scales and is cross-referenced with existing classification schemes such as the EUNIS and Natura 2000 habitats classes. We present the typology and its main classification criteria, and discuss options for its future implementation

Ecosystem service research in grasslands at 31 experimental farms, networks and demonstration platforms across Europe

Grassland research stations and experimental farms are essential for applied grassland science and related outreach activities. A large proportion of the experiments conducted at these stations aims to test methods to optimize the ecosystem services (ES) delivered by permanent grasslands. We used the framework of the multi-actor research project SUPER-G to assess a selection of experiments recently conducted, completed (since 2011), and planned at 31 European experimental research stations, farms, or networks. We further provide an overview of the ES measured at these experiments. Results show that on average two ES were assessed per experiment. The most frequent ES measured were production (87% of all experiments), followed by the supporting ES biodiversity (59%) and climate regulation (33%). Our overview on ES research at European research stations highlights that permanent grassland is a multifunctional ecosystem that provides many benefits to society. Yet, research considering more than two ES is still relatively rare and should thus be strengthened in the future

European permanent grasslands mainly threatened by abandonment, heat and drought, and conversion to temporary grassland

Permanent grassland (PG) covers 35% of the agricultural area in the EU-28. Across Europe, PG exists in many contrasting managed or unmanaged environments where it contributes to feed supply, biodiversity, carbon sequestration, aesthetic value, recreation, clean water and prevention of soil loss. The delivery of these PG ecosystem services is under threat by land use change, climate change and sub-optimal management. We carried out a survey among experts to assess the threats within their countries. Respondents described the main PG-types, together with their areas, and assessed to what extent a particular PG-type is threatened by intensification, land use change, climate change or nitrogen (N) depositions. Threats were scored on a three-point scale: no, small or great. Replies were received from 11 countries (CH, CZ, DE, ES, HU, IT, ME, NL, PL, SE, UK), representing the main biogeographic zones in Europe. The dataset contained 83 PG- types on a total area of 25 Mha. Abandonment, heat and drought stress and conversion to temporary grassland were considered as the largest threats, each considered as a great threat on PG-types covering 8 to 9 Mha (~35%). The second largest group comprised N depositions, conversion to arable land and intensification, each as a great threat on PG-types covering 4 to 5 Mha (~20%)

Delivery of ecosystem services from permanent grasslands in Europe: a systematic review

Permanent grasslands cover 34% of the European Union’s agricultural area and are vital for the delivery of essential ecosystem services. Over recent decades, permanent grasslands have suffered a significant decline and land use change continues to threaten their area. We performed a systematic review on the multifunctionality of permanent grasslands in Europe, examining the effects of land use change and management practices on 18 ecosystem service indicators. Based on the evidence in 696 out of 70,456 screened papers, we found that both land use change and intensification decreased multifunctionality. A lower management intensity was associated with benefits for biodiversity, climate regulation and water purification, but had a negative effect on the provision of high-quality animal feed. Increasing the number of species in the sward enhanced multifunctionality of permanent grassland without significant trade-offs such as losses in production. We suggest that a combined approach of protection and management extensification will help secure multiple benefits from permanent grasslands