Weed Harrowing and Inter-Row Hoeing in Organic Grown Quinoa (Chenopodium Quinoa Willd.)

Weeds, with their negative influence on both yield and quality, constitute a major problem in the organic production of quinoa, a potential new seed crop for protein feed and human consumption in Europe. To attain effective weed control, mechanical weeding strategies, such as weed harrowing and inter-row hoeing, were studied. Weed harrowing operates over the entire plot with flexible tines, affecting both crop and weeds, whereas inter-row hoeing is performed between the rows, aiming only at the weeds. The study showed that both hoeing and harrowing reduced the quinoa density in one out of two years, whereas there was no effect on quinoa density in the other year. Yield was increased by both methods, but hoeing increased yield more than harrowing due to better weed control. Regression analysis showed that crop yield was related to weed dry matter and showed no indications of higher crop damage associated with weed harrowing. Protein content was low when weeds were not treated, and increased significantly when weeds were controlled. As a conclusion, inter-row hoeing was more efficient than weed harrowing with respect to weed control; however, weed harrowing should be optimized in future trials in narrow row spacing systems, and the results indicate that weed harrowing can be used as a supplement to inter-row hoeing.