Performance of Soybean Maturity Groups 2 to 4 Under Irrigated and Unirrigated Conditions In Eastern New Mexico.

Soybeans (Glycine max) are valuable for their oil, which can be converted to biodiesel as well as other uses, and the solvent extracted meal, which is used as a protein supplement for livestock. But little is known about soybean performance in the Southern High Plains of eastern New Mexico. In 2010, New Mexico State University’s Agricultural Science Center at Tucumcari compared soybean maturity groups 2, 3, and 4, each represented by 2 varieties, under unirrigated and irrigated conditions using 6 x 6 Latin Squares. Plots were harvested by maturity group when pod shattering began for the earlier-maturing variety within the group. Data were analyzed using SAS PROC MIXED procedures. In addition to significant (P < 0.05) differences between irrigated and unirrigated systems and among soybean maturity groups, irrigation level and maturity group interacted to affect pods/plant, yield/plant, and yield/acre. Greater pods/plant and yield/plant led to higher yields for unirrigated group 2 (693 lb/ac vs. 491 and 484 lb/ac for groups 3 and 4, respectively) and irrigated group 3, while irrigated group 4 had higher yields due to plant population (1039b, 1227ab, 1320a lb/ac for groups 2, 3, and 4, respectively). Soybean maturity group 2 appears best for unirrigated systems in the Southern High Plains of eastern New Mexico while group 4 would be appropriate for irrigated situations with appropriate variety selection.