Influence of Soil Moisture and Ambient Temperature on Yield and Quality of Alfalfa Forage1

Abstract

AbstractAlfalfa grown at high soil moisture stress in growth chamber and field studies yielded less dry matter than that grown at low soil moisture stress. A higher percentage of leaves, higher percentage of in vitro digestibility (IVDDM), and lower percentages of acid detergent fiber (ADF) and lignin (ADL) often occurred in forage grown at high soil moisture stress. Soil moisture did not affect the percentage of crude protein (CP) consistently.Under controlled‐environment conditions, alfalfa grown at high temperatures (27 C day/21 C night) yielded less dry matter and had lower digestibility and higher ADF and ADL than that grown at lower temperatures (16 C day/10 C night). This occurred even though percentage of leaves and CP increased at high temperatures. The lowest ADF concentration (indicative of highest quality) occurred at low temperatures and high soil moisture stress; also, IVDDM was among its highest and ADL among its lowest levels under these conditions (also indicative of high quality).Low temperatures and low soil moisture stress were generally associated with a higher yield of a relatively higher quality forage than were high temperatures and high soil moisture stress.Crude protein failed to estimate alfalfa quality when forage was produced in diverse climates, confirming earlier reports.