sorghum, production practices, nutrients, yield


A field experiment was conducted at the North Central Kansas Experiment Field near Scandia, KS, in the summer of 2014 to evaluate diverse cropping systems approaches to closing sorghum yield gaps. Yield gaps can be understood as the difference between maximum and attainable on-farm yields. The approach taken in this project is system wide, rather than focusing on one factor and its interaction. The factors that were tested include narrow row spacing; plant population; balanced nutrition practices, including various timings of nitrogen, phosphorus, and potassium (NPK) and micronutrient applications; crop protection with fungicide and insecticide applications; plant growth regulator effects; and the use of precision ag technology for maximizing yields, including a GreenSeeker meter (Trimble Navigation, Westminster, CO) for more precisely determining fertilizer nitrogen needs of sorghum. Grain sorghum yields ranged from 95 to 125 bu/a in Scandia under dryland conditions. One of the lowest yields was obtained when common practices were implemented (treatment 10), with an average 103 bu/a, whereas maximum yield was registered with the “kitchen sink (all inputs are applied)” treatment (treatment 1), with an average 115 bu/a. Notwithstanding the lack of treatment difference, the grain sorghum yield gap from a common practice to “kitchen sink” was 12 bu/a.