Dwarf amaranth (Amaranthus macrocarpus Benth.) is a problematic broadleaf weed in many crops in Australia; however, no information is available on the germination ecology of this species. Seeds from two populations of this species were collected from Hillston, NSW, Australia (D-P-01), and Yandilla, QLD, Australia (D-P-02). Seeds were germinated at a range of constant (20 to 45 C) and alternating temperatures (30/20, 35/25, 40/30, and 45/35 C day/night). For the constant temperature treatments, the highest germination occurred at 35 C for D-P-01 (89%) and D-P-02 (82%). Germination was higher at the alternating day/night temperature of 40/30 C for both populations D-P-01 (91%) and D-P-02 (85%). Seed germination of both populations was stimulated by light, which indicates a great amount of emergence of A. macrocarpus can occur on bare ground such as crop seed beds. Results also revealed that this species tolerates a moderate level of salinity and can germinate in slightly alkaline soil conditions. The emergence of this species was highest (47%) for the seed buried at 0.5-cm depth in grey cracking alkaline soil compared with seed buried at the same depth in acidic red soils. These results suggest that soil inversion by tillage to bury weed seeds below their maximum emergence depth could serve as an important tool for managing A. macrocarpus. The results from this study will help in developing more sustainable and effective integrated weed management tactics for the control of this weed and weeds with similar responses in summer cropping systems.

中文翻译：

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矮苋（Amaranthus macrocarpus）的萌发生态：澳大利亚棉花种植系统中的一种新兴杂草

矮苋菜（苋菜Benth.) 在澳大利亚的许多作物中是一种有问题的阔叶杂草；然而，没有关于该物种萌发生态学的信息。从澳大利亚新南威尔士州希尔斯顿 (DP-01) 和澳大利亚昆士兰州扬迪拉 (DP-02) 收集了来自该物种两个种群的种子。种子在恒定（20 至 45 C）和交替温度（30/20、35/25、40/30 和 45/35 C 日/夜）范围内发芽。对于恒温处理，DP-01 (89%) 和 DP-02 (82%) 在 35 C 时发芽率最高。对于群体 DP-01 (91%) 和 DP-02 (85%)，在 40/30 C 的昼夜交替温度下，发芽率更高。两个种群的种子萌发均受到光的刺激，表明大量出苗A. 大果可以发生在裸露的地面上，例如作物苗床。结果还表明，该物种可以耐受中等水平的盐分，并且可以在微碱性土壤条件下发芽。与埋在酸性红土中相同深度的种子相比，在灰色开裂碱性土壤中埋入0.5 cm深度的种子，该物种的出现率最高（47%）。这些结果表明，通过翻耕将杂草种子埋在其最大出苗深度以下的土壤反转可以作为管理杂草种子的重要工具。A. 大果. 这项研究的结果将有助于开发更可持续和有效的综合杂草管理策略，以控制这种杂草和在夏季种植系统中具有类似反应的杂草。