Narrow-windrow burning has been a successful form of harvest weed seed control in Australian cropping systems, but little is known about the efficacy of narrow-windrow burning on weed seeds infesting U.S. cropping systems. An experiment was conducted using a high-fire kiln that exposed various grass and broadleaf weed seeds to temperatures of 200, 300, 400, 500, and 600 C for 20, 40, 60, and 80 s to determine the temperature and time needed to kill weed seeds. Weeds evaluated included Italian ryegrass, barnyardgrass, johnsongrass, sicklepod, Palmer amaranth, prickly sida, velvetleaf, pitted morningglory, and hemp sesbania. Two field experiments were also conducted over consecutive growing seasons, with the first experiment aimed at determining the amount of heat produced during burning of narrow windrows of soybean harvest residues (chaff and straw) and the effect of this heat on weed seed mortality. The second field experiment aimed to determine the effect of wind speed on the duration and intensity of burning narrow windrows of soybean harvest residues. Following exposure to the highest temperature and longest duration in the kiln, only sicklepod showed any survival (<1% average); however, in most cases, the seeds were completely destroyed (ash). A heat index of only 22,600 was needed to kill all seeds of Palmer amaranth, barnyardgrass, and Italian ryegrass. In the field, all seeds of the evaluated weed species were completely destroyed by narrow-windrow burning of 1.08 to 1.95 kg m−2 of soybean residues. The burn duration of the soybean harvest residues declined as wind speed increased. Findings from the kiln and field experiments show that complete kill is likely for weed seeds concentrated into narrow windrows of burned soybean residues. Given the low cost of implementation of narrow-windrow burning and the seed kill efficacy on various weed species, this strategy may be an attractive option for destroying weed seed.

中文翻译：

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使用加热和窄条堆燃烧对美国南部作物中的杂草进行种子破坏

在澳大利亚的种植系统中，窄堆燃烧是一种成功的收获杂草种子控制形式，但对于窄堆燃烧对侵染美国种植系统的杂草种子的功效知之甚少。使用高火窑进行实验，将各种草和阔叶杂草种子暴露在 200、300、400、500 和 600 摄氏度的温度下 20、40、60 和 80 秒，以确定所需的温度和时间杀死杂草种子。评估的杂草包括意大利黑麦草、稗草、强生草、镰刀菌、帕尔默苋菜、刺西达、天鹅绒、去核牵牛花和大麻田菁。在连续的生长季节还进行了两次田间试验，第一个实验旨在确定在燃烧狭窄的大豆收获残留物（谷壳和稻草）过程中产生的热量以及这种热量对杂草种子死亡率的影响。第二个田间试验旨在确定风速对燃烧狭窄的大豆收获残留物的持续时间和强度的影响。在窑中暴露于最高温度和最长持续时间后，只有镰状足有存活（平均<1%）；然而，在大多数情况下，种子被完全破坏（灰烬）。只需要 22,600 的热量指数就可以杀死帕尔默苋菜、稗草和意大利黑麦草的所有种子。在田间，被评估的杂草种子全部被 1.08 至 1.95 kg m 的窄条焚烧破坏 第二个田间试验旨在确定风速对燃烧狭窄的大豆收获残留物的持续时间和强度的影响。在窑中暴露于最高温度和最长持续时间后，只有镰状足有存活（平均<1%）；然而，在大多数情况下，种子被完全破坏（灰烬）。只需要 22,600 的热量指数就可以杀死帕尔默苋菜、稗草和意大利黑麦草的所有种子。在田间，被评估的杂草种子全部被 1.08 至 1.95 kg m 的窄条焚烧破坏 第二个田间试验旨在确定风速对燃烧狭窄的大豆收获残留物的持续时间和强度的影响。在窑中暴露于最高温度和最长持续时间后，只有镰状足有存活（平均<1%）；然而，在大多数情况下，种子被完全破坏（灰烬）。只需要 22,600 的热量指数就可以杀死帕尔默苋菜、稗草和意大利黑麦草的所有种子。在田间，被评估的杂草种子全部被 1.08 至 1.95 kg m 的窄条焚烧破坏 只有镰状足有任何存活（平均<1%）；然而，在大多数情况下，种子被完全破坏（灰烬）。只需要 22,600 的热量指数就可以杀死帕尔默苋菜、稗草和意大利黑麦草的所有种子。在田间，被评估的杂草种子全部被 1.08 至 1.95 kg m 的窄条焚烧破坏 只有镰状足有任何存活（平均<1%）；然而，在大多数情况下，种子被完全破坏（灰烬）。只需要 22,600 的热量指数就可以杀死帕尔默苋菜、稗草和意大利黑麦草的所有种子。在田间，被评估的杂草种子全部被 1.08 至 1.95 kg m 的窄条焚烧破坏-2的大豆残渣。大豆收获残留物的燃烧持续时间随着风速的增加而减少。窑炉和田间试验的结果表明，对于集中在狭窄的烧焦大豆残渣堆中的杂草种子，可能会完全杀死。鉴于实施窄条堆燃烧的成本低以及对各种杂草的杀种效果，这种策略可能是破坏杂草种子的一个有吸引力的选择。