Planting Date Affects Rainfed Sorghum Forage Yields in Semiarid, Subtropical Environments

Abstract

Increasingly, sorghum [Sorghum bicolor L. (Moench)] forage producers in semiarid regions must maximize yield under rainfed conditions. Dry matter hay yields of a brown midrib (BMR) photoperiod‐sensitive sorghum‐sudangrass (Sorghum bicolor var. Sudanese) hybrid (PS) and a BMR forage sorghum (FS) were compared in four randomized complete blocks over four planting dates each in 2004 and 2005 in a one‐cut system without irrigation at New Mexico State University's Agricultural Science Center at Tucumcari. On average, PS outyielded FS (1.38 vs. 0.99 tons/acre, respectively, P < 0.01) and sorghum forages planted in May or early June outyielded sorghum forages planted in late June or July (1.66, 1.45, 0.93, and 0.70 tons/acre for sorghum forages planted approximately 19 May, 9 June, 30 June, and 21 July, respectively, P < 0.05). The year × planting date × sorghum forage type (FS or PS) interaction also was significant, likely because the positive effect of differences in precipitation distribution on yield of PS. While yields of FS and PS were similar when planting took place in a dry seedbed in 2004, PS had greater yields than FS when planted before the end of June in moist soil in 2005. Late‐season precipitation may impact yield of sorghum forages planted after mid June.

Alfalfa Rotation Strategy and Soil Type Influence Soil Characteristics and Replanted Alfalfa Yield in the Irrigated Semiarid, Subtropical Southwestern USA

“…Wheat was harvested for forage at the boot stage in early May of Year 2 and sorghum-sudangrass was managed as single-cut system each year with a late-season harvest in Year 1 (for SS2) and mid-summer harvest in Year 2 (SS1, SS2, and WW/SS) to allow for alfalfa replanting in late summer (Table 1). Because of the photoperiod-sensitive nature of the SS cultivar, all harvests for that species were at a vegetative stage [11]. During Years 1 and 2, alfalfa was harvested from the ALF treatment plots as growth permitted.…”

“…Temperatures in Years 1 and 2, during the rotation phase and for alfalfa establishment, were conducive to the growth of each crop during their respective growing season (Table 3) [11,14,15]. Irrigations were applied to supplement less than adequate precipitation and promote crop establishment and production during those years.…”