سیدحسن موسوی فضل - استادیار، بخش تحقیقات فنی و مهندسی کشاورزی، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان سمنان، سازمان تحقیقات، آموزش و ترویج کشاورزی، شاهرود، ایران

In order to study the effects of irrigation water (۵۰, ۷۵ and ۱۰۰%) and potassium fertilizer (۰, ۵۰ and ۱۰۰% required potassium fertilizer) on the dynamic of root, yield and shoots of sorghum varieties (Pegah (P), KSF۲ (KS) and Speedfeed (S)), a research was conducted in the Agricultural and Natural Resources Research Center of Semnan Province (Shahrood) in ۲۰۱۴. In this study the factors were irrigation water (W), potassium fertilizers (K) and varieties (V) of forage sorghum. The experimental treatments were arranged based on split plot factorial design using a randomized complete block design with three replications. Irrigation water was calculated with Penman-Monteith method. Drip irrigation was used as irrigation system. Sampling was carried out from the roots in three phases during the season. The root volume was determined with immersion in water method. Shoots parameters such as leaf area, leaf dry weight, stem dry weight and shoot weight were measured. The results showed that the effects of irrigation water, potassium fertilizer and sorghum varieties on the forage of yield, volume and dry weight of roots and shoots plant were significant. The highest yield was obtained from the W۱۰۰K۱۰۰ treatment for Pegha variety. The maximum water use efficiency was obtained from the W۷۵K۱۰۰Vp treatment. The W۷۵K۱۰۰Vp treatment was identified as a superior treatment. The final production value of forage varieties were obtained ۱۹۲۰۰۰۰, ۳۱۸۰۰۰۰ and ۳۹۸۰۰۰۰ rials for Speedfeed, KSF۲ and Pegha, respectively.

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