| In this investigation, the alfalfa used was Longdong cultivar of Gansu province (Medicago sativa L.), on the Loess Plateau of China. We set different cutting times and different intervals to analyse its effect on growth, hay yield, nutritive value, to provide scientific basis for the management of alfalfa fields. The results were as follows:1. The influence of cutting on growthThe number of plants with at least one flower increased first and then decreased, but the number of plants with at least one pod increased slowly over time. The plant number, stem number and height of plant showed a trend of increase as growth continued, but basal area decreased slowly. There was a significantly positive correlation between the total dry matter and average plant number, average stem number, height of plant, basal area. Average stem number, height of plant and basal area were significantly correlated with average plant number. Additionally, there was a significantly positive correlation between average stem number and height of plant and basal area (P<0.01). There was no correlation between plant height and basal area.2. The influence of cutting on hay yieldThe yield varied when cut at different stages of development. Peak yield was obtained in the full flowering stage (beginning of pod stage), which was 17th of June in 2009 and 27th of May in 2010, and hay yield reduced as growth continued, as did the ratio of leaf to stem. Maximum hay yield of 2009 was in June 17 and August 20 mowing, as 2275.2±360.4 kg/ha, the ratio of stem and leaf was 1.86±0.282. Maximum hay yield of 2010 was in June 16 and August 16 mowing, as 2004.3±197.8 kg/ha, the ratio of stem and leaf was 1.5±0.087.3. The influence of cutting on nutritive valueAt first cutting time, The percentage of NDF, ADF and CF increased as growth continued, but Ash and CPcontent decreased. The results showed that the nutritive value of regrowth varied with different cutting times. NDF, ADF and CF decreased with little time to grow, whereas Ash and CP increased. Conversely, NDF, ADF and CF increased with the passage of time, whereas Ash and CP decreased. |
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