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Fluid Journal : Summer 2015
14 The Fluid Journal Summer 2015 Dr. Ignacio Ciampitti is an Assistant Professor in Crop Production and Cropping Systems Specialist and Ms. Bailey McHenry is a graduate student at Kansas State University. Figure 3. Sorghum grain harvest index, estimated as the grain yield to the whole-plant biomass ratio, under diverse cropping systems approaches for the Rossville site during the 2014 growing season. Treatment description: 1= Kitchen Sink (KS); 2= Plant Density (PD); 3= Row Spacing (RS); 4= Pre-plant nitrogen only (Pre-N); 5= Fungicide/Insecticide (F/I); 6= Micronutrients (Micros); 7= Plant Growth Regulator (PGR); 8= N and Phosphorous (P) (NP); 9= Chloride (Cl); 10= Farmer Practices (FP); 11= KS + extra 50 lbs N/acre (KS+N). Figure 4. Plant biomass versus stem volume calculation, implemented via determination of the stem diameter (maximum diameter at stem base) and plant height (distance from soil surface [stem base] to the collar of the uppermost extended leaf) at the flowering stage for sorghum crop at Ottawa and Scandia sites, 2014 season. tool for estimating plant growth rates under diverse production practices for sorghum crops. Summing up The 2014 sorghum growing season presented early-season challenges in plant uniformity and biomass conversion due to late-season drought. At Rossville when water was a non- limiting factor, yield variability (expressed as a CV%) was minimized and yield advantage between the farmer practice and the use of a balanced approach (“kitchen sink”) was maximized. Yield gain was primarily related to whole- plant biomass and biomass conversion (measured via grain HI). This study demonstrates that closing sorghum yield gaps can be partially achieved when variability induced via weather and/or soil type is reduced. When water was not limiting sorghum yields, a balanced nutrient application and optimization of production practices did increase grain sorghum yields (“kitchen sink” vs. “farmer practice”). Evaluation of nutrient uptake and partitioning in different plant fractions is critical for properly understanding the effect of diverse practices. Balanced nutrient application for maximizing yields under crop management practices should be further studied for grain sorghum under diverse environments. Further site x year evaluation is needed to confirm the findings that high-yielding grain sorghum systems can be maximized via balancing nutrient applications and pushing production intensity (e.g. narrowing rows).