影响苜蓿自然干燥的主要环境因子研究

An investigation of the main environmental factors affecting the natural drying of alfalfa for hay,and hay quality

为深入解析影响优质苜蓿干草生产的关键环境因子,为我国北方地区生产优质苜蓿干草提供理论依据和技术支持。通过测定紫花苜蓿不同收获期(不同茬次、不同花期)的干燥速率、叶绿素含量、主要营养成分(粗蛋白,CP;中性洗涤纤维,NDF;酸性洗涤纤维,ADF;相对饲用价值,RFV)等指标筛选苜蓿自然干燥的最佳环境条件,并通过各项指标与环境因子的相关性,明确影响苜蓿自然晾晒的主要环境因子。结果表明:1)苜蓿自然晾晒中,影响苜蓿干燥速率的主要环境因素是:太阳辐射强度、气温、空气湿度和风速;影响苜蓿叶绿素含量的主要环境因素是:太阳辐射强度、气温和风速;影响苜蓿CP、NDF、ADF及RFV等营养指标的主要环境因素是:气温、空气湿度和风速,其中温度、风速对CP的影响极显著,空气湿度对NDF、ADF及RFV的影响极显著。综合衡量,影响苜蓿干燥的主要环境因素是气温、空气湿度、太阳辐射强度以及风速。2)通过对各收获期苜蓿干燥速率、叶绿素含量及主要营养物质含量的综合分析,在与试验地气候条件相似地区,苜蓿自然干燥的最佳环境条件是:温度日均值26.29~27.95℃,空气湿度日均值34.74%~36.71%,太阳辐射强度日均值268.36~422.33 W·m^(-2),风速日均值1.59~1.82 km·h^(-1)。

This article aims to provide a thorough analysis of the key conditions required for production of high-quality alfalfa hay,and to provide theoretical and technical guidelines for the production of good quality alfalfa hay in northern China.We evaluated the optimal environmental conditions for natural drying of alfalfa hay by measuring the drying rate,chlorophyll content and the main nutrient components:crude protein(CP),neutral detergent fiber(NDF),acid detergent fiber(ADF),relative feeding value(RFV)and other indicators.Data were collected for different stubble heights and flowering stages and from the correlation between various hay characteristics and environmental variables,the main environmental factors that affect the natural drying of alfalfa were clarified.The results showed that:1)During the natural drying of alfalfa,the main environmental factors that affected the drying rate of alfalfa were solar radiation intensity,temperature,air humidity and wind speed.The main factors that affected alfalfa chlorophyll content were solar radiation intensity,temperature and wind speed.The main factors that affected CP,NDF,ADF and RFV of alfalfa hay were temperature,air humidity and wind speed.Among these,temperature and wind speed had significant effects on CP,and air humidity had significant effects on NDF,ADF and RFV.Overall,temperature,air humidity,solar radiation intensity and wind speed were the main environmental factors affecting the drying rate of alfalfa hay.2)Through a multivariate analysis of the drying rate,chlorophyll content and nutritive value data for alfalfa hay in each harvest period,the optimal ranges of environmental conditions for natural drying of alfalfa hay in northern China,or other areas with similar climate conditions,are:daily average temperature,26.29-27.95℃;daily average air humidity,34.74%-36.71%;daily average solar radiation intensity,268.36-422.33 W·m^(-2)and daily average wind speed,1.59-1.82 km·h^(-1).