###### Abstract  
The Montado is a Mediterranean agro-forestry-pastoral ecosystem. Knowledge of pastures' nutritional value is critical for farm managers' decision-making. Laboratory determinations are very expensive, destructive and costly, in terms of time and labour. The objective of this experimental work was to calibrate and validate a portable near-infrared spectrometer (micro-NIR) to predict the nutritive value (neutral detergent fibre, NDF and crude protein, CP) of pastures in the peak of spring 2021. Thus, a total of 87 pasture samples were collected at eight experimental fields located in the Alentejo, Southern region of Portugal. The results show good correlations between in-situ micro-NIR measurements and pasture NDF reference values (R\({}^{2}\) of 0.73 and 0.69 for calibration and validation models, respectively), and a moderate correlation between micro-NIR measurements and pasture CP reference values (R\({}^{2}\) of 0.51 and 0.36 for calibration and validation models, respectively). These results show the potential of this tool for the quick evaluation of pasture quality and constitute a starting point for future work, which should include the monitoring of temporal variability (throughout the entire vegetative cycle of the pasture) and spatial (with geo-referenced information) diversity of pastures characteristic of the Montado ecosystem in the Mediterranean region. micro NIR; portable NIR spectrometry; pastures; crude protein; fibre; real-time; decision making +
Footnote †: journal: Medical Science  
0000-0001-8000-0001-8000][PERSON]  
0000-0001-8000-0001-8000][PERSON]  
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0000-0001-8000-0001-80001-8000]Celek for updates  
0000-0001-8000-80001-80000]Celek for updates  
0000-0 by the Mediterranean climate. This climate is characterized by hot, dry summers and mild winters, with large rainfall irregularities [6] great seasonality and variability [5]. This variability in rainfall in each year and between years, means that pasture production (quantity and quality) is also irregular. According to [PERSON] et al. [7] the inter-annual variability of precipitation may explain the differences in the quantity and quality of pasture, with biomass production and its nutritional value increasing with the annual increase in precipitation. On the other hand, the fertility of the soils, the diversity in the floristic composition, the trees and grazing animals, also contribute to great variability in productivity and quality of the pasture [8]. In this sense, also, [PERSON] et al. [9] report that the nutritional value of pasture can be very variable within the same field, during the growing period, due to nutritional deficiencies, frost, and drought or grazing. Knowledge of the nutritional value of pasture and its availability over time can lead to improvements in production systems and grazing management of ruminants [9; 10; 11]. According to [PERSON] et al. [12] grazing management decisions are made as a function of pasture quality and availability. Therefore, monitoring pasture quality leads to increased farm efficiency [13]. Real-time information about the nutritional value of the pasture will allow the farmer to make more informed decisions regarding animal supplementation [11]. The survey of the spatial and temporal variability of biomass, based on the cutting and collection of pasture samples, is a destructive, time-consuming, expensive [13; 14], and labour-demanding method, impracticable from a practical perspective [15], which has led to a growing interest in expeditious methods [16]. The time required to sample processing [11] and to obtain the results of the determinations of the nutritional value of the pasture [10], carried out in the laboratory, is also another indirect cost, often preventing the use of these determinations by the farmer for decision-making [12; 13; 17].