| Biomass dynamics of every stubble of spring-sowed alfalfa in the loess plateau of Longdong |
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| DOI：10.7606/j.issn.1000-7601.2009.01.35 |
| Key Words: Longdong loess plateau alfalfa biomass dynamics |
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| Abstract: |
| The observations and the experiments of the biomass of spring-sowed alfalfa were carried out in the loess plateau of Longdong from 2003 to 2005.The results showed that the transition period of the plant height growth of spring-sowed annual alfalfa from slow to rapid is between the divaricating stage and the budding stage.The transition period of the plant height growth from rapid to slow comes after the budding stage.As for biennial and triennial alfalfa, clipping three times within a year is suitable.The average day-to-day increase of fresh grass weight of the first and second stubble alfalfa is obviously greater than that of third stubble alfalfa.Most instances showed that the average day-today increase of fresh grass weight of triennial alfalfa is grearer than biennial alfalfa.The maximum fresh grass and hay weight of alfalfa present in first and second stubble.For the first and second stubble alfalfa, fresh grass weight accounts for 76.9%～84.3% and hay weight accounts for 79.1%～86.3% of all three stubbles.The ratio of fresh grass weight to hay weight of every stubble alfalfa decreases obviously after budding stage and falls off to minimum in blooming stage (clipping ago) .The interannual variation and the regional difference of climatic conditions affect the growth of alfalfa.If the need of water being enough for alfalfa growth, the areas where daily range of temperature is comparatively wide will be favorable to the substance accumulation of alfalfa. |