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Knowledge on sustainable grassland management is available in the large body of literature. However, it is unclear where to look for it, and what is really relevant to the many interrelated challenges of sustainable grassland management. This special issue illustrates options to fill some of those gaps. This editorial introduces the Special Issue entitled “Grassland Management for Sustainable Agroecosystems”. Two review articles deal with (i) concepts for monitoring grassland degradation (by Tiscornia et al. Agronomy 2019, 9, 239) and (ii) impacts of alternative management practices and disturbances (by Wagle and Gowda et al. Agronomy 2018, 8, 300). One paper (by Steiner et al. Agronomy 2019, 9, 699). summarized a series of papers of the special issue. Other topics covered include four main aspects: (I) Landscape features (Ravetto Enri et al. Agronomy 2019, 9, 333), two papers by Northup et al. Agronomy 2019, 9, 329, Northup et al. Agronomy 2019, 9, 281, and Ma et al. Agronomy 2019, 9, 238; (II) climate (Zhou et al. Agronomy 2019, 9, 219, Starks et al. Agronomy 2019, 9, 235, and Moinet et al. Agronomy 2019, 9, 124); (III) soil fertility (Franzluebbers et al. Agronomy 2019, 9, 204, Poblete-Grant et al. Agronomy 2019, 9, 191); and (IV) one on modeling (Puche et al. Agronomy 2019, 9, 183). Two additional papers are from Andueza et al. Agronomy 2019, 9, 273 (on the feed value of barn-dried hay) and Úbeda et al. Agronomy 2019, 9, 340 (on the role of prescribed burns).

This study describes how management of grasslands is included in the Organizing Carbon and Hydrology in Dynamic Ecosystems (ORCHIDEE) process-based ecosystem model designed for large-scale applications, and how management affects modeled grassland–atmosphere CO2 fluxes. The new model, ORCHIDEE-GM (grassland management) is enabled with a management module inspired from a grassland model (PaSim, version 5.0), with two grassland management practices being considered, cutting and grazing. The evaluation of the results from ORCHIDEE compared with those of ORCHIDEE-GM at 11 European sites, equipped with eddy covariance and biometric measurements, shows that ORCHIDEE-GM can realistically capture the cut-induced seasonal variation in biometric variables (LAI: leaf area index; AGB: aboveground biomass) and in CO2 fluxes (GPP: gross primary productivity; TER: total ecosystem respiration; and NEE: net ecosystem exchange). However, improvements at grazing sites are only marginal in ORCHIDEE-GM due to the difficulty in accounting for continuous grazing disturbance and its induced complex animal–vegetation interactions. Both NEE and GPP on monthly to annual timescales can be better simulated in ORCHIDEE-GM than in ORCHIDEE without management. For annual CO2 fluxes, the NEE bias and RMSE (root mean square error) in ORCHIDEE-GM are reduced by 53% and 20%, respectively, compared to ORCHIDEE. ORCHIDEE-GM is capable of modeling the net carbon balance (NBP) of managed temperate grasslands (37 ± 30 gC m−2 yr−1 (P < 0.01) over the 11 sites) because the management module contains provisions to simulate the carbon fluxes of forage yield, herbage consumption, animal respiration and methane emissions.

Can emerging technologies improve the modelling of grass growth?. 2017 EFITA WCCA Congress. European conference dedicated to the future use of ICT in the agri - food sector, bioresource and biomass sector

International audience; Grassland based systems offer farmers the three pillars of sustainability: economic, environmental and social. Two reasons are proposed for Europe to remerge with a better focus on grazed grass and grazing system efficiency; (1) the economic and demographic situation is rapidly changing in the world, and (2) environment sustainability can no longer be comprised. Economic success in grazing systems is defined by pasture utilisation which, in turn is positively affected by pasture availability and stocking rate (cows/ha) and negatively affected by the amount of feed purchased. Success in this regard will need to build on that principle by growing and utilising more grass per hectare, converting the grass as efficiently as possible into saleable product with a labour and capital efficient system of milk production. The objective of this paper is to outline the reasons for why grazed grass in the cow’s diet should be increased and to discuss how such an increase can be achieved.

We have set up a facility allowing steady state (CO2)-C-13 labeling of short stature vegetation (12m(2)) for several years. C-13 labelling is obtained by scrubbing the CO2 from outdoors air with a self- regenerating molecular sieve and by replacing it with C-13 depleted (-34.7 +/- 0.03 parts per thousand) fossilfuel derived CO2 The facility, which comprises 16 replicate mesocosms, allows to trace the fate of photosynthetic carbon in plant-soil systems in natural light and at outdoors temperature. This method was applied to the study of soil organic carbon turnover in temperate grasslands. We tested the hypothesis that a low disturbance by grazing and cutting of the grassland increases the mean residence time of carbon in coarse (> 0.2 mm) soil organic fractions. Grassland monoliths (0.5 x 0.5 x 0.4 m) were sampled from high and low disturbance treatments in a long-term (14 yrs) grazing experiment and were placed during two years in the mesocosms. During daytime, the canopy enclosure in each mesocosm was supplied in an open flow with air at mean CO2 concentration of 425 mu mol mol(-1) and delta C-13 of -21.5 +/- 0.27 parts per thousand. Fully labelled mature grass leaves reached a delta C-13 of -40.8 (+/- 0.93) and - 42.2 parts per thousand (+/- 0.60) in the low and high disturbance treatments, respectively, indicating a mean C-13 labelling intensity of 12.7 parts per thousand compared to unlabelled control grass leaves. After two years, the delta C-13 value of total soil organic matter above 0.2mm was reduced in average by 7.8% in the labelled monoliths compared to controls. The isotope mass balance technique was used to calculate for the top ( 0 - 10 cm) soil the fraction of C-13 labelled carbon in the soil organic matter above 0.2mm (i.e. roots, rhizomes and particulate organic matter). A first order exponential decay model fitted to the unlabelled C in this fraction shows an increase in mean residence time from 22 to 31 months at low compared to high disturbance. A slower decay of roots, rhizomes and particulate organic matter above 0.2mm is therefore likely to contribute to the observed increased in soil carbon sequestration in grassland monoliths exposed to low disturbance.