Publication Date
1989
Description
The nutritive value for ruminants of lucerne forage may be characterized both by the In Vitro Digestibility of Dry Matter (IVDDM) and by the Nitrogen content (N % ) which determine the energy and nitrogen values. These two characteristics are linked to the Leaf/Stem ratio (L/S) (Demarquilly, 1966). But for the same L/S ratio, different IVDDM and N % can be obtained according to the biochemical composition of leaves and stems separately. The effect of water deficit on the quality of forage of lucerne can be considered separately on the morphological composition and on the biochemical composition. L/S is generally increased by drought (Vough and Marten, 1971). The direct effect of water deficit on IVDDM and on N % of stems and leaves has been less studied and published results are often contradictory. So Vough and Marten (1971) observed either increases or decreases of the N % of total aerial biomass for plants having experienced drought. Cruz & Lemaire (1986) have demonstrated that the variations in N % of aerial biomass cannot be interpreted without referring to the dry matter yield, because of the dilution of N during the course of dry matter accumulation. In this experiment, we tried to analyse separately the effect of water deficit on morphological composition of lucerne forage (L/S ratio) and the dynamics of decrease of IVDDM and N % of total aerial biomass, leaf biomass and stem biomass during the course of the regrowth of lucerne subjected (dry plots) or not subjected (irrigated plots) to water deficit.
Citation
Lemaire, G; Durand, J L.; and Lila, M, "Effect of Water Deficit on the Quality of Lucerne (Medicago sativa L.)" (2025). IGC Proceedings (1989-2023). 42.
https://uknowledge.uky.edu/igc/1989/session7/42
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Effect of Water Deficit on the Quality of Lucerne (Medicago sativa L.)
The nutritive value for ruminants of lucerne forage may be characterized both by the In Vitro Digestibility of Dry Matter (IVDDM) and by the Nitrogen content (N % ) which determine the energy and nitrogen values. These two characteristics are linked to the Leaf/Stem ratio (L/S) (Demarquilly, 1966). But for the same L/S ratio, different IVDDM and N % can be obtained according to the biochemical composition of leaves and stems separately. The effect of water deficit on the quality of forage of lucerne can be considered separately on the morphological composition and on the biochemical composition. L/S is generally increased by drought (Vough and Marten, 1971). The direct effect of water deficit on IVDDM and on N % of stems and leaves has been less studied and published results are often contradictory. So Vough and Marten (1971) observed either increases or decreases of the N % of total aerial biomass for plants having experienced drought. Cruz & Lemaire (1986) have demonstrated that the variations in N % of aerial biomass cannot be interpreted without referring to the dry matter yield, because of the dilution of N during the course of dry matter accumulation. In this experiment, we tried to analyse separately the effect of water deficit on morphological composition of lucerne forage (L/S ratio) and the dynamics of decrease of IVDDM and N % of total aerial biomass, leaf biomass and stem biomass during the course of the regrowth of lucerne subjected (dry plots) or not subjected (irrigated plots) to water deficit.
