VI. CROP AND WEATHER CONDITIONS
Weather conditions before and at planting, throughout the growing season, and even during harvest play a major role in the evolution of the sorghum plant and ultimately in the sorghum grain yield and quality. For U.S. sorghum production, two main harvest areas, Early Harvest Area (EHA) and Late Harvest Area (LHA), are highlighted.
For the Early Harvest Area (EHA), the 2015 growing season started late due to delayed planting. This was followed by a wet early-growth period (from planting until half-bloom) compared to a historical period of 1895 to 2015. Wet conditions lingered across the Texas coastal area of the EHA while drier conditions developed within the continental area1 during the reproductive phase until harvest. The 2015 sorghum crop condition for the EHA improved as the growing season progressed from early in the season to harvest2. The following list highlights the key events of the EHA for the 2015 growing season:
- Temperatures during the early planting time frame (from February until April) averaged near or below the historical averages, and provided cool temperatures for emergence conditions.
- Above-average moisture conditions during the early planting period and continued wet conditions (wettest on record) until mid-pollination (from February until June and July) slowed plant growth.
- Near-average temperatures in the continental area and above-average temperatures near the coastal areas from April to June potentially impacted crop development during the floret fertility and final grain formation stages, thereby possibly impacting yields.
1The continental area is the area in Texas that is not along the coast.
2The U.S. Department of Agriculture (USDA) rates the U.S. sorghum crop weekly during the production cycle. The rating is based on yield potential, and plant stress due to a number of factors including extreme temperatures, excessive or insuffcient moisture, disease, insect damage, and/or weed pressure.
For the Late Harvest Area (LHA), the 2015 growing season experienced delayed planting due to wet conditions during the early part of the typical planting season (April until June). This was coupled with average or aboveaverage temperatures compared to historical temperature averages (1985 – 2015). The 2015 sorghum crop condition for the LHA remained fairly constant from the early vegetative stages until harvest. The following list highlights the key events of the LHA for the 2015 growing season:
- Non-uniform precipitation events during planting time (May through June) produced well-above-average wet conditions in some areas and near- or just-above-average conditions in other areas. These conditions caused delayed and slow planting progress.
- Near- and above-average temperatures from April to June helped with planting progress and emergence.
- Heavy rainfall and normal-to-cool temperatures from the vegetative to early reproductive phase presented a challenge for growing conditions by slowing crop growth and delaying sorghum heading in some areas. Slow growth conditions around pollination favored floret fertility and the grain formation process, thereby diminishing the impact of any stress that might have occurred at this stage.
- In most of the LHA, temperatures for the mid-pollination period were cooler than normal, while temperatures for grain filling in September were warmer than normal.
- Warm temperatures and dry conditions from grain filling to harvest accelerated maturity and natural drying, and hastened harvesting during October.
The following sections describe how the 2015 growing-season weather impacted the sorghum development and yield for both the Early and Late Harvest Areas in the U.S. sorghum production regions.