153. Nutritive Effects of Wind on Drought Stressed Forage Sorghum

Abstract The Southern Great Plains is a major producer of crop and livestock commodities. However, the region is renowned for its variable weather patterns, making it more vulnerable to climate change. Variable environmental conditions, such as increased temperature, altered rainfall, and amplified wind velocity are expected to have the greatest effect on plant and animal production in the future. Unfortunately, the impact of abiotic factors on plant morphology and forage nutritive value is limited. A better understanding of the effects of abiotic stress on forage species is a prerequisite to combat climate change and maintain productivity. Sorghum (Sorghum bicolor (L.) Moench) is one of the primary grain and forage crops grown in the region due to its ability to thrive in semi-arid conditions and its versatility as a hay or silage crop. Because of this, it was selected as the model plant to determine how wind affects morphology and forage nutritive value. Using a completely randomized design, fifteen 0.09 m3 pots containing conventional forage sorghum were separated into three wind treatments: 0 KPH (W0), ∼10 KPH (W1), and ∼13 KPH (W2) wind velocity using pedestal fans. All plants were irrigated at 65% ETc, with fans applying wind 12 hours per day (0800 – 2000 h). Pots were clipped once 75% of the plants within a pot achieved the soft dough stage. Full bromatological assessment was performed by Servi-Tech Inc. using NIRS, with nitrate content assessed in-house via colorimetric methods. Statistical analyses were performed in PROC MIXED of SAS 9.4 using a random intercept model. Total biomass at the soft dough stage was greatest for W0, with no difference between W1 and W2 (P ≤ 0.05). However, there was no notable difference in leaf:stem ratio across treatments. The W0 treatment had increased TDN compared to the W1 and W2 treatments, 64.47% vs. 60.55 and 61.06%, respectively (P ≤ 0.05). When assessing crude protein, W1 and W2 had a greater concentration than W0, 9.22 and 9.29% vs. 8.11%, respectively (P ≤ 0.05). Nitrates were substantially higher in the wind treatments, with nitrate levels approximating 181, 357, and 397 ppm for W0, W1, and W2, respectively (P ≤ 0.05). Results indicate that wind influences both plant morphology and nutritive value of forage sorghum, providing key information on how abiotic stress can impact regional production and the potential ripple effects throughout the livestock production chain.