Determination of nitrogen fertilizer requirement on sorghum based on leaf color chart

Nowadays, implementation of simple and efficient methods for determining nitrogen needs has been considered in various plants. The simplest and most efficient methods for appreciate nitrogen requirement determination is leaf color chart (LCC). To determine of nitrogen fertilizer requirement in forage sorghum using leaf color chart, an experiment was conducted as factorial arrangement based on complete randomized block design with three replications at Agriculture and Natural Resources Research Station of Sabzevar in 2012 growing season. The factors were nitrogen rate in four levels including conventional (150), 25, 50, and 75 kg.ha-1 N and LCC scores was less than 4 and 5. The highest plant height, leaf dry weight, number of leaves per plant, biological yield and protein percentage were obtained in 75 and 50 kg.ha-1 nitrogen application. Using different amounts of nitrogen with reduction of LCC to 5 led to higher plants, more leaf dry weight, leaf numbers per plant, biological yield and protein content than using nitrogen with reduction of LCC to 4. On the whole, 50 kg.ha1 nitrogen with reduction of LCC to 5 was the best treatment for the highest quantity and quality yield achievement for forage sorghum. Also, LCC can be applied easily to determine sorghum nitrogen equipment.