Long‐term evolution and prediction of feed value for permanent mountain grassland hay: Analysis of a 32‐year data set in relation to climate change

Abstract

Elevation of mean air temperature related to climate change speeds up plant maturity, which influences mostly forage feed value. The objective of the study was to assess variation in hay quality harvested over 32 years at the same experimental site, and whether feed value is better predicted by combining agro‐climatic variables with chemical composition. From 1979 to 2010, the in vivo digestibility (OMd) and voluntary dry matter intake (VDMI) of 271 hays, harvested during the first vegetation cycle on permanent grasslands, were measured in sheep. Over 32 years, the mean air temperature between February and August increased significantly by 1.34°C. Cutting date was advanced by 6 days, but the average sum of temperature at cutting (ST) increased significantly by 13%. Crude protein (CP) content declined (−22%, p < .001), crude fibre content increased (+8%, p < .001), OMd decreased (−3%, p = .012) and VDMI increased (+9%, p = .011). Changes in the chemical composition and OMd were consistent with the increase in ST. Finally, the prediction of OMd from CP and crude fibre contents (R2 = .57, RMSE = 2.99) was slightly improved by the addition of ST and hay drying time (R2 = .60, RMSE = 2.83). Climate change may have a negative indirect effect on hay quality if an earlier cutting date does not compensate for its effect on the faster maturation of the plants. Moreover, agro‐climatic criteria could help to monitor and predict hay quality in relation to intra‐ and inter‐annual climatic changes.

Changes in the Nutritional Value of Timothy (Phleum pratense L.) Biomass as a Response to Varied Organomineral Treatment

“…The content of brous fractions, which increases with plant aging, translates into dry matter intake (DMI) 41 20 were similar to the results of the present research.…”

“…An important element of the nutritional value of roughage is its digestibility. It depends on many factors such as harvest time or weather conditions 38,39,40,41 . Roughage digestibility is dependent on the content of NDF and ADF 36 .…”

Dynamic simulation of management events for assessing impacts of climate change on pre-alpine grassland productivity

“…Overall, the simulated shifts of the first cutting event compares well with other observations. Deroche et al (2020) reported a 14-day earlier start of the vegetation period for a grassland site (900−1200 m.a.s.l.) in France for a +1 °C air temperature increase in the period 1979–2010.…”

“…The stimulating effect on plant biomass production caused by increasing temperatures and higher atmospheric CO 2 concentrations influences future cutting and fertilization regimes ( Chang et al, 2017 ; Soussana and Lüscher, 2007 ). According to local agricultural practice, farmers cut the grass regularly based on yield demands and maturity stage as influenced by weather and soil conditions ( Deroche et al, 2020 ), thus significant changes in biomass development will likely change the timing of cutting and associated fertilization events throughout the year ( Thivierge et al, 2016 ). Recent climate change has been found to affect species’ phenology in mid- and higher latitudes, especially regarding the earlier onset of spring events with mean global average changes of 2.3 days per decade ( Parmesan and Yohe, 2003 ).…”

Different growth response of mountain rangeland habitats to annual weather fluctuations

“…While change in land management by pastoralism remains the biggest change factor in alpine flora [4,5,6], it is also significantly affected by variations in growth conditions [7,8,9]. In the alpine domain, the seasonal dynamics and productivity of grassland is affected by changes in temperature, water availability, and snow persistence [10,11], with variable altitudinal distribution of the species [12,13]. A comprehensive yet detailed monitoring of the evolution of mountain grassland is therefore of primary importance to correctly manage the pastoral activity, maximise its sustainability, and preserve the biodiversity of these unique environments.…”