Dataset for: Effect of nitrogen fertilization on potato late blight in the field in Huancayo, Junin Peru

The effect of nitrogen (N) fertilization on the development of potato late blight disease, caused by Phytophthora infestans (Mont.) de Bary, was studied through field experiments in two locations in Peru (Huancayo and Oxapampa). These datasets correspond to the field experiments in Huancayo. Three levels of N (0, 160, and 320 kg/ha) and three levels of fungicide were applied in all combinations on two potato (Solanum tuberosum L.) varieties with different levels of resistance (18 treatments), and in four repetitions. N had no effect on the disease when severity was very low or high. At intermediate levels of disease severity, increased N led to increased disease. In Huancayo, the effect of 0 vs. 160 kg·ha-1 of N on the more susceptible variety was negligible because of increased late blight. For the more resistant variety, late blight had little effect on yield when N was applied at 0 or 160 kg·ha-1. Increasing the N fertilization rate to 320 kg·ha-1 did not further increase yield in the absence of late blight, but decreased it sharply in the treatments where the disease was present because no fungicides were applied. These results indicate the importance of considering N fertilization levels in integrated management schemes for potato late blight, and in comparison of results across experiments. If farmers want to increase potato yields with N fertilizer, they may need to use more fungicides or varieties with higher resistance.

本研究针对由致病疫霉（Phytophthora infestans (Mont.) de Bary）引发的马铃薯晚疫病，在秘鲁的万卡约（Huancayo）与奥克萨潘帕（Oxapampa）两处试验地点开展田间试验，以探究氮肥（N）对该病害发生发展的影响。本数据集对应万卡约地点的田间试验结果。
试验设置3个氮肥水平（0、160、320 kg/ha）与3个杀菌剂水平，将二者全部组合后，应用于2个抗性水平存在差异的马铃薯（Solanum tuberosum L.）品种，共计18个处理组，且设置4次生物学重复。
试验结果显示：当病害严重度极低或极高时，氮肥对病害发生无显著影响；在病害严重度处于中等水平时，施氮量增加会导致病害加重。在万卡约试验中，对于感病性更强的品种，由于晚疫病发生程度较高，0与160 kg·ha⁻¹的氮肥处理间的病害差异可忽略；对于抗病性更强的品种，当施氮量为0或160 kg·ha⁻¹时，晚疫病对产量几乎无影响。当施氮量提升至320 kg·ha⁻¹时，在未发生晚疫病的处理组中，产量未出现进一步提升；但在未施用杀菌剂且发生病害的处理组中，产量会急剧下降。
本研究结果表明，在马铃薯晚疫病的综合防控方案制定以及跨试验结果比对过程中，氮肥施用水平的考量具有重要意义。若农户希望通过增施氮肥提升马铃薯产量，可能需要配合使用更多杀菌剂，或选用抗性更高的马铃薯品种。