苜蓿、无芒雀麦混播与单播群落总糖及氮素含量动态

The Dynamics of Total Sugar and Nitrogen Content in Communities of Medicago varia,Bromus inermis in Mixture and Single

对二龄苜蓿与无芒雀麦混播与单播群落地上与地下部分总糖及氮素含量季节动态进行了测定,结果表明:苜蓿地上部分总糖含量呈双峰型,峰值分别出现在结实期和生长末期。无芒雀麦地上部总糖含量呈单峰型,果后营养期地上部总糖含量最高,生长末期地上部总糖含量下降。苜蓿根系总糖含量变化动态呈双峰型,而无芒雀麦呈三峰型。单播无芒雀麦、苜蓿地上部含N量随物候期的推移呈下降趋势;混播草地含N量在9月初降至最低后又上升。苜蓿和无芒雀麦根部含N量动态均呈双峰型,第一个峰值在春季,第二个峰值在秋初。混播增加了无芒雀麦地上和地下部分的N素含量。

The experiment was conducted in Tongliao, Inner Mongolia Autonomous Region in 2004. The total sugar and nitrogen content in herbages on mixture grasslands composed of Medicago varia and Bromus inermis and single grasslands was studied. The results showed that aboveground total sugar content of mixture and single Medicago varia presented double apex pattern. And aboveground total sugar content of mixture and single Bromus inermis presented one apex pattern, and reached highest in the early autumn. Dynamics of total sugar content in Medicago varia＇s roots was double apex pattern, and that of Bromus inermis＇s roots presented three apex pattern. The aboveground nitrogen content of Bromus inermis and Medicago varia in the single grassland both dearease by degrees along with phenophase＇s process. , and that of mixture grassland became to increase in the late autumn. The nitrogen content in the roots of Bromus inermis and Medicago varia were both higher in early growing period, then they dropped down after they came into their reproductive growth stage, rised up after mature period and dropped down again in late growing period. Mix-sowing increased Bromus inermis＇ aboveground and belowground nitrogen content.