ABSTRACT

Cover cropping provides versatile benefits for sustainable agriculture, but many cover crops are potential host plants for pathogens such as Sclerotinia sclerotiorum (Lib.) de Bary. Therefore, 14 cover crops were investigated for their interaction with sclerotia, topsoil moisture and temperature in two consecutive field trials in East Austria. In July, after the cover crops were sown, sclerotia were inoculated at 3 cm soil depth in two mesh tubes per plot with 1×1 mm and 3×10 mm mesh size and remained until March. Cover crops did not affect decay of sclerotia, but sclerotia declined faster in 3×10 mm mesh compared to 1×1 mm (75.7 and 54.7%; respectively). Degree days reached the required 500 °C for apothecia development in September in both years, but only in year 1 was topsoil moisture sufficient for apothecia development. Nonmetric dimensional scaling revealed that, among others, topsoil temperature in March was significant for sclerotia germination in spring and was independent of plant biomass. There are indications that Poaceae such as sorghum × Sudan grass and Sudan grass can stimulate early germination under cover crops, causing vulnerability of sclerotia to degradation. This could reduce the pathogen pressure for the subsequent irrigated cash crops.

摘要

覆盖作物为可持续农业提供了多种好处，但许多覆盖作物是病原体（如核盘菌）的潜在宿主植物（自由）德巴里。因此，在东奥地利的两次连续田间试验中，研究了 14 种覆盖作物与菌核、表土水分和温度的相互作用。7 月，覆盖作物播种后，在每块 1×1 mm 和 3×10 mm 网孔大小的两个网管中，以 3 cm 土壤深度接种菌核，并保持至 3 月。覆盖作物不影响菌核的腐烂，但与 1×1 mm 相比，3×10 mm 网格中的菌核下降更快（分别为 75.7% 和 54.7%）。在这两个年份的 9 月，度日均达到了子囊发育所需的 500 °C，但只有在第 1 年，表土水分才足以使子囊发育。非度量尺度尺度显示，除其他外，3 月表土温度对春季菌核萌发具有重要意义，并且与植物生物量无关。有迹象表明，高粱×苏丹草、苏丹草等禾本科植物可刺激覆盖作物下的早期萌发，导致菌核易退化。这可以降低后续灌溉经济作物的病原体压力。