Abstract: Nutrient loss of alfalfa in the drying process has always been a key technical problem restricting the development of alfalfa industry. Therefore, speeding the drying rate and shortening the drying time become significant for alfalfa hay drying and processing. The moisture contents of ‘Golden Queen’ alfalfa and major meteorological parameters are determined to investigate the regularity of alfalfa moisture evaporation during drying process and the main factors of alfalfa drying rate. Results showed that in the natural drying process, alfalfa drying rate was initially fast then slow; alfalfa hay would get damp and lose nutrients overnight. Fracturing stalk process could accelerate the drying process of alfalfa effectively. This process shortened the drying time about 24 hours but the compressed alfalfa damped more easily than control. The drying rate of alfalfa had extremely significant positive correlation with solar radiation intensity, air temperature and wind speed, but had extremely significant negative correlation with air humidity and atmosphere water potential and had no significant positive correlation with alfalfa moisture. The influence factors of alfalfa drying rate were ordered as solar radiation intensity>air temperature>atmosphere water potential>air humidity>wind speed>alfalfa moisture.

Key words: Alfalfa, Environmental factors, Water potential, Drying rate, Moisture migration

摘要： 苜蓿(Medicago sativa L.)在干燥过程中的营养损失一直是制约苜蓿产业发展的关键技术难题,如何加快干燥速率,缩短干燥时间成为当今苜蓿干草调制加工研究的热点。试验以'金皇后’紫花苜蓿为原料,通过对其含水量及主要气象参数的测定,研究了苜蓿干燥过程中的水分散失规律及影响苜蓿干燥速率的主要因子,旨在为探讨加快苜蓿干燥的途径提供依据。结果表明:苜蓿在自然干燥过程中,干燥速率呈先快后慢的变化趋势,而且夜间返潮严重,营养损失较大;压扁处理可有效加快苜蓿干燥,含水量从约80%降至10%左右需56 h,较未压扁苜蓿缩短干燥时间约24 h,但压扁苜蓿更易返潮;苜蓿干燥速率与太阳辐射强度、气温和风速极显著正相关,而与苜蓿含水量的正相关关系不显著,同时与空气湿度和大气水势有极显著的负相关关系,各因子对苜蓿干燥速率的影响大小顺序为:太阳辐射强度>气温>大气水势>空气湿度>风速>苜蓿含水量。

关键词: 苜蓿, 环境因子, 水势, 干燥速率, 水分迁移