|KOTHARI, KRITIKA - Texas A&M University|
|ALE, SRINIVASULU - Texas A&M Agrilife|
|Baumhardt, Roland - Louis|
Submitted to: Frontiers in Sustainable Food Systems
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/13/2019
Publication Date: 1/22/2020
Citation: Mauget, S.A., Kothari, K., Leiker, G.R., Emendack, Y., Xin, Z., Hayes, C.M., Ale, S., Baumhardt, R.L. 2020. Optimizing dryland crop management to regional climate. Part II: U.S. Southern High Plains sorghum production. Frontiers in Sustainable Food Systems. 3:119. https://doi.org/10.3389/fsufs.2019.00119.
Interpretive Summary: West Texas is the second largest sorghum production region in the U.S., but as Ogallala aquifer levels drop sorghum farmers need to know how and when to plant their crops to make better use of summer rainfall. To help answer those questions, ARS scientists in Lubbock used a sorghum crop model driven by weather inputs from 21 west Texas weather stations during 2005-2016 to test the effects of planting date, fertilizer and plant density on yields. The highest grain yields resulted from the latest planting date (July 5) and the lowest plant density (10,000 plants per acre), but applied nitrogen had minor yield effects. Thus these crop simulations recommend planting in late June or early July at a low plant density as part of management practices that maximize the yields and profits of west Texas sorghum farmers.
Technical Abstract: Sorghum’s heat and drought tolerance make it, together with upland cotton, one of two crops produced profitably under dryland conditions in the U.S. Southern High Plains (SHP). Here, a simulation-based method evaluates management options that increase median SHP dryland sorghum yields and estimates those practice’s yield risk effects. This method generates climate-representative distributions of grain yields via a crop model driven by weather inputs from 21 SHP weather stations during 2005-2016. Optimal management practices for current SHP climate conditions were sought by generating yield distributions under 32 management options defined by 4 planting dates, 4 plant densities, and applied or no applied N. The highest median grain yields resulted from management options with the latest planting date (July 5) and the lowest plant density (24.7 K plants ha-1), while applied N had essentially no yield effect. Increased yields with later planting dates are consistent with sorghum’s growth cycle and SHP summer rainfall climatology. Confirming the low plant density yield effect may require additional field studies, as supporting evidence of higher yields at lower densities from other SHP field and modelling studies is mixed. These crop simulations, however, suggest late June to early July planting as part of management practices that maximize yields in dryland SHP sorghum production.