Herbage mass thresholds rather than plant phenology are a more useful cue for grazing management decisions in the mid-north region of South Australia
Herbage mass thresholds rather than plant phenology are a more useful cue for grazing management decisions in the mid-north region of South Australia
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DOI：
10.1071/rj10003
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发表时间：
2010-12
影响因子：
1.2
通讯作者：
L. Kahn;J. Earl;M. Nicholls
中科院分区：
文献类型：
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作者：
L. Kahn;J. Earl;M. Nicholls
2000- 2005年期间在南澳中北部进行了研究，以评估不同放牧管理线索对草地组成和生产的影响。管理线索的基础上日历，植物物候或牧草质量阈值放牧排除作为对照。有五个放牧处理：（i）区域实践（RP），其中绵羊放牧持续4月至12月;（ii）秋季休息，其中绵羊放牧仅限于6月至12月;（iii）春季休息，其中绵羊放牧仅限于4月至8月;（iv）高密度和短时间（HDSD），其中牧草质量阈值确定放牧发生时和持续时间;（五）无（零）放牧的国内草食动物。平均每年估计的牧草质量是最高的NIL和HDSD和列入估计的绵羊的牧草消费量导致最大的初级植物生产在HDSD。多年生牧草对牧草质量的贡献随着RP和季节性放牧处理而下降。多年生牧草的频率不受放牧处理，但随着时间的推移，在RP和季节性治疗的多年生牧草的数量增加。HDSD可以维持基底覆盖，而裸地则随着RP和季节性处理而增加。凋落物积累在NIL，但这是与常年基底覆盖下降。季节性放牧处理没有提供一个优势RP和似乎没有好处，包括物候在管理决策。相比之下，HDSD导致了一个稳定和富有成效的草地生态系统，载畜率估计为78%以上，比其他治疗。这些功能为南澳中北部未来的行业采用提供了理想的组合。
Research was conducted in the mid-north of South Australia over the period 2000–05 to evaluate the effects of different grazing management cues on composition and production of a grassland. The management cues were based on calendar, plant phenology or herbage mass thresholds using grazing exclusion as a control. There were five grazing treatments: (i) regional practice (RP), where sheep grazed continuously for the period April–December; (ii) autumn rest, where sheep grazing was restricted to June–December; (iii) spring rest, where sheep grazing was restricted to April–August; (iv) high density and short duration (HDSD), where herbage mass thresholds determined when grazing occurred and for what duration; and (v) nil (NIL) grazing by domestic herbivores. Mean annual estimates of herbage mass were highest for NIL and HDSD and inclusion of the estimate of herbage consumption by sheep resulted in greatest primary plant production in HDSD. The contribution of perennial grasses to herbage mass declined with RP and seasonal grazing treatments. Frequency of perennial grasses was unaffected by grazing treatment but the number of perennial grass plants increased over time in RP and seasonal treatments. HDSD allowed maintenance of basal cover whereas bare ground increased with RP and seasonal treatments. Litter accumulated in NIL but this was associated with a decline in perennial basal cover. Seasonal grazing treatments did not provide an advantage over RP and there appeared to be no benefit from including phenology in management decisions. In contrast, HDSD resulted in a stable and productive grassland ecosystem, with stocking rate estimated at 78% greater than other treatments. These features offer a desirable mix for future industry adoption in the mid-north of South Australia.