To determine the effect of plant density and humic acid on canola yield, a 2-year field experiment was conducted as a factorial split-plot during the 2014–2016 cropping years. The factors included two humic acid levels (humic acid solution at 3/1000 [v/v] concentration and distilled water) and three plant densities (40, 60, and 80 plants per m²) in the main plots and six canola genotypes (Ahmadi, Okapi, Opera, Nafis, Karaj1, and SW102) in the subplot. The results showed a significant decrease in the grain and oil yield when plant density increased from 40 to 80 plants per m², by 57 and 59%, respectively. The oil quality was also effected by the plant density, so the erusic acid and glucosinolate contents increased twofold at 80 plants m². The grain and oil yield were significantly higher in plants treated with humic acid compared to controls, by 5.4 and 5.8%, respectively. Moreover, the foliar application of humic acid enhanced the oil quality of canola genotypes through a significant decrease in erusic acid and glucosinolate contents. However, there was no significant decreasing effect of humic acid on the density-induced yield loss and the oil yield reduction. Therefore, the increase in canola yield might be achieved by selecting the optimum density and improving the nutritional condition of the soil.

为了确定植物密度和腐殖酸对双低油菜籽产量的影响，在2014-2016年的种植年中，进行了为期2年的田间试验，作为因子分解图。这些因素包括主要地块中的两种腐殖酸水平（浓度为3/1000 [v / v]的腐殖酸溶液和蒸馏水）和主要样地中的三种植物密度（每m ² 40、60和80株植物）和六种油菜基因型（子图中的Ahmadi，Okapi，Opera，Nafis，Karaj1和SW102）。结果表明，当植物密度从每m ^2的40株增加到80株时，谷物和油的产量显着下降，分别降低了57％和59％。油的质量也受植物密度的影响，所以在80株m ²处，芥酸和芥子油苷的含量增加了两倍。。与对照相比，用腐殖酸处理过的植物的谷物和油料产量分别高出5.4和5.8％。此外，通过显着降低芥酸和芥子油苷含量，叶面施用腐殖酸提高了菜籽油基因型的油品质。但是，腐殖酸对密度引起的收率损失和油收率降低没有明显的降低作用。因此，可通过选择最佳密度和改善土壤的营养状况来实现双低油菜籽产量的增加。