Differential Response of Tomato and Lambsquarter Seedlings to Potassium Level1

Sand culture experiments showed that lambsquarters ( Chenopodium album L.) required greater amounts of K in the nutrient media for optimum growth than did tomato (Lycopersicon esculentum Mill.). When grown in competition, the ratio of tomato to lambsquarters decreased with increasing K level in the media. At all 5 K levels employed, lambsquarter shoots contained a greater percentage of dry matter and a greater K concentration than did tomato shoots. Optimum growth for lambsquarter required shoot K concentration twice as high as tomato. In contrast to shoots, lambsquarter roots had a higher concentration of K only at lower media K levels while tomato roots had a higher concentration of K at higher K levels. Total K accumulation per unit of root mass was greater for lambsquarters at lower K levels but equal for the species at high K levels.