Sainfoin is a perennial legume with high dry matter (DM) yield during spring growth. The aim of this work was to study the evolution of forage yield and nutritional characteristics over a three-year period. Samples were collected at progressive morphological stages, from vegetative to seed pod. The mean stage by weight (MSW), yield, DM content, crude protein (CP), NDF, condensed tannin, gross energy (GE), organic matter digestibility (OMD) and the net energy for lactation (NE L) were determined. The forage characteristics were regressed on the growing degree days (GDD) and the MSW. The DM yield increased from 0.5 to over 8 t•ha-1 as the growth stage progressed from vegetative to flowering, while the leaf to stem ratio decreased from 8 to 0.3 and the CP from 280 to 130 g•kg-1 DM. The NDF ranged from 230 to 502 g•kg-1 DM and was highly related to the GDD with a R 2 of 0.92. The OMD decreased with increasing GDD without any differences over the years (R 2 = 0.83). Unexpectedly, the codified morphological stage was unable to predict the OMD evolution, as the code scale was not sensitive enough to describe structural variations that affect the crop over the bud stage to flowering. growing degree days / DM yield / digestibility / NDF / codified morphological stage Résumé-Évolution du rendement et de la qualité du sainfoin (Onobrychis viciifolia Scop.) dans le 1 er cycle de croissance printanier. Le sainfoin est une légumineuse vivace avec une productivité élevée et une forte teneur en matière sèche de la coupe printanière. Le but de ce travail a été d'étudier l'évolution de la production et de la qualité du fourrage durant le cycle printanier sur une période de trois ans. Des échantillons de fourrage ont été récoltés durant la phase végétative jusqu'au grossissement des graines. Sur chacun d'eux on a procédé aux évaluations suivantes : stade morphologique pondéré (MSW), rendement, contenu en matière sèche (DM), protéines brutes, NDF, tannins condensés, énergie brute, digestibilité in vitro de la matière organique (OMD) et énergie nette pour la lactation (NE L). Les caractéristiques qualitatives du fourrage ont été mises en relation avec la somme de degrés-jours GDD, et le stade morphologique codifié (MSW). Le rendement en matière sèche a varié de 0,5 t•ha-1 jusqu'à plus de 8 t•ha-1 depuis le début de la végétation jusqu'à la floraison, tandis que le rapport feuilles/ tiges s'est fortement réduit de 8 à 0,3 juste après l'apparition des tiges florales. Le contenu en protéine brute a diminué très rapidement de 280 à 130 g•kg-1 DM au stade de bourgeons floraux. Le NDF s'est révélé fortement corrélé avec la GDD (R 2 = 0,92), en passant de 230 à 502 g•kg-1 DM. La OMD a diminué suite à l'augmentation de la GDD, sans aucune différence entre les années (R 2 = 0,83). Le stade morphologique codifié, contrairement à ce que l'on attendait, ne décrit pas correctement l'évolution de la OMD car la codification du stade morphologique n'est pas assez sensible pour détecter les variations très brusques de la structure de la culture entre...

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quality during the spring growth cycle would allow targeting of harvests or grazing to desired levels of nutritive A precise prediction of changes in digestibility of grasses during composition to meet specific animal requirements. It is the growth cycle would allow targeting of harvests to desired levels also necessary for optimization of ration composition of nutritive composition to meet specific animal requirements. In this study, regression analysis was used to formulate and test prediction with respect to maximal production, minimal excretion equations for organic matter digestibility (OMD) of standing crops of undigested material, and minimal cost (Hvelplund et of Italian ryegrass (Lolium multiflorum Lam.) with codified morphoal., 1995). logical stage, canopy age, growing degree days (GDD), and N fertiliza-Although intake is more important than digestibility tion as independent variables. The field study was conducted for 7 yr in assessing forage quality, extensive research has been with six Italian ryegrass cultivars, diversified for ploidy and earliness, devoted to measuring digestibility and relating it to feed grown in the western Po Valley (Italy). Nitrogen fertilizer was applied characteristics because digestibility can be accurately at various rates as top dressing. Sequential harvesting from early measured with relative ease compared to intake (Mervegetative to full flowering provided herbage samples (n ϭ 153) varytens, 1994). ing in age and stage of development. The 0-400 classification systemIn temperate grasses, digestibility depends mainly on that was used to evaluate the morphological stage included four primary stages: vegetative, elongation, inflorescence emergence, and the growth stage, the growth cycle, and the species (Van flowering. The OMD decreased from 928 to 576 g kg Ϫ1 OM, as the Soest, 1994). Digestibility generally decreases with adherbage aged. All cultivars responded in the same way during the vancing age, especially during the first growth cycle. whole growth cycle. Morphological stage was a better predictor of This decline results from the interaction of factors such OMD than GDD or age in days, with a higher r 2 (0.88) and a lower as increased fiber concentration in plant tissues (Wilson root mean square error (28.0 g kg Ϫ1 OM). Nitrogen fertilization slightly et al., 1991), increased lignification during plant develdecreased digestibility. The developed equation tested on an indepenopment (Morrison, 1980), and the different leaf/stem dent set of farm scale data (n ϭ 34) showed that this codified morphoratio (Hides et al., 1983). Terry and Tilley (1964) relogical stage system can provide a rapid and easy estimate of Italian ported that at early stages of growth, all parts of the ryegrass digestibility in the field.

The management of symbiotic Microbial Biota (MB) in the soil as agents that promote the yield and health of crops, is aimed at inducing modifications of the phenotype of plants, both over and under the ground. It is here shown, in Sorghumsudanensis plants, that: i) a simple response to MB inoculation is the result of the fall out of the raw pH; ii) the simple NIR scans of leaves can be considered to rapidly classify the outcomes; iii) the raw pH can be considered a key-variable of leaf modifications. An experiment was carried out on Sorghumsudanensis. The plants were seeded in pots and grown for 66 d, and then a control non-inoculated group (C) was compared with thirteen Arbuscular Mycorrhizae (AM) Glomus inoculated groups and with two commercial MB products. A total of 374 raw pH measurements conducted on the leaves showed that the 5.18 pH units in the C group were scaled by -1.9% (P<0.0336) in the MB group and by -3.4% in the AM group (P<0.0001), with a relevant diversity between groups. Direct discrimination of these three groups, by means of smart NIR-SCIO, showed a % reclassification of the C, MB and AM groups of 74%, 59% and 96% in the fresh leaves and of 65%, 51% and 94% in the dried ground leaves, respectively. The composition of the dried leaves, based on a set of 14 variables predicted via NIRS models, plus the total foliar dry weight and percentage, showed a typical increase in protein, ash and hemicellulose, and a typical decrease in the cellulose, dry matter, crude fiber and crop maturity index. These variables were related to the foliar pH, as a key-variable, by means of a PLS standard model (R2 0.81) in which a low pH steadily favored the dry mass weight and, to a lesser extent, the hemicellulose and the digestible NDF contents; on the other hand, a high pH increased the dry matter percentage and the cellulose content of the leaves. As expected, the leaves of the inoculated plants showed a more juvenile ontogenic status. The epigean botanical modifications can be considered harmonic expressions of a luxuriant symbiosis, as testified by the homologous NIR categorization. The outlook for a symbiotic agriculture, with mycorrhizal plants, should consider the raw pH as a multifaceted variable.