Interseeding Spring and Winter Small Grains for Enhanced Forage Production in Cool-Season Forage Systems.

Roughly half of the six million wheat acres in Texas are grazed on any given year. Therefore, forage production in small grains systems is incredibly important and increasing fall forage production without impacting grain yield or spring forage production would benefit Texas wheat growers. Spring small grains do not require vernalization and growth is strictly based on heat units. If planted early in the fall, spring types will initiate reproductive growth and begin stem elongation and rapid biomass production unlike winter types that stay vegetative until spring. An experiment examining the impact of interseeding spring and winter small grains was conducted over three locations (College Station, McGregor and Comanche, TX) and three years (2013-14 through 2015-16 season). Three spring interseeding percentages (0% spring, 25% spring, and 50% spring) were planted at four seeding rates (56, 84, 112, 140 kg ha^-1) with winter wheat. In 2013-14, no differences were detected for forage production when spring wheat was interseeded with winter wheat over four harvests under a forage only system. In 2014-15, spring barley was interseeded with winter wheat and increased fall forage yield by 1.30 t DM ha^-1 (483%) when interseeded at 50%. Interseeding barley did reduce spring forage, but total season forage production was still 0.97 t DM ha^-1 greater than 100% winter wheat. Similar trends were observed at McGregor in 2014-15 and at Comanche in 2015-16. Seeding rate was not significant at either location. Oat, spring wheat and spring barley interseeding treatments (1:1 ratio) were also included in statewide cool-season forage variety trials in the 2015-16 season where the spring barley treatment ranked first out of 40 entries at Comanche and College Station. These results suggest interseeding spring barley with winter wheat can enhance fall forage production and therefore total season forage yield for producers grazing wheat.