The Perennial Grain Crop Thinopyrum intermedium (Host) Barkworth & D.R. Dewey (Kernza™) as an Element in Crop Rotations: A Pilot Study on Termination Strategies and Pre-Crop Effects on a Subsequent Root Vegetable

Intermediate wheatgrass (IWG) may benefit soil fertility in crop rotations. To investigate termination strategies, i.e., autumn ploughing (AP), autumn harrowing (AH) and spring harrowing (SH) on a five-year-old IWG stand, a pilot study was performed. After the treatments, beetroots were sown and the IWG plants were counted twice during the beetroot growing season. The number of IWG plants was highest (20) after the SH strategy, intermediate (14) after the AH, and lowest (3) after the conventional termination strategy, AP. After the first plant count, the plots were subject to mechanical weeding in the form of a stale seedbed (i.e., harrowing twice before sowing). At beetroot harvest, the number of IWG plants was low (3 in SH and AH, 0 in AP) and similar between the treatments. The beetroot production was highest after AP and lowest in SH, and intermediary in AH, which showed no difference from AP and SH. At beetroot harvest, the weed biomass did not differ between the termination strategies. The weeds were mainly annuals. There were no differences in soil bulk density between termination strategies. Our results show that shallow soil tillage is enough to terminate IWG, as long as it repeated. We suggest further studies that investigate the dynamics of crop sequences with IWG, and how to benefit from this crop in rotations.

Optimal Planting Date of Kernza Intermediate Wheatgrass Intercropped with Red Clover

Intermediate wheatgrass (IWG) is a new perennial dual-use crop for grain and forage with growing interest among farmers. Intercropping IWG with red clover may increase yield and nutritive value through nitrogen transfer. IWG and red clover planting timing can affect grain and forage yield, and there has not been previous research on this management practice. At two locations (Arlington and Lancaster, WI, USA) a factorial experiment was established two years with two factors: (1) IWG planting date (August through October, and April) and (2) red clover planting season (in the fall with IWG or frost seeded in the next spring). Yield data were collected for two subsequent years. Grain yield was maximized at 515 kg ha−1 and 423 kg ha−1 at Arlington and Lancaster when planted by 26 August and 13 September, respectively. Planting date influenced grain yields in the first harvest year but not in the second. Seeding red clover in the spring increased IWG and red clover biomass compared to seeding it in the fall. In Wisconsin, planting IWG by early September at the latest and planting red clover in the spring is recommended to maximize grain yield.

Comparing the Deep Root Growth and Water Uptake of Intermediate Wheatgrass (Kernza®) to Alfalfa.

AimsWater is the most important yield-limiting factor worldwide and drought is predicted to increase in the future. Perennial crops with more extensive and deep root systems could access deep stored water and build resilience to water shortage. In the context of human nutrition, perennial grain crops are very interesting. However, it is still questionable whether they are effective in using subsoil water. We compared intermediate wheatgrass (Kernza®) Thinopyrum intermedium, a perennial grain crop, to alfalfa Medicago sativa, a perennial forage, for subsoil root growth and water uptake.MethodsUsing TDR sensors, deuterium tracer labelling, minirhizotrons and the Hydrus-1D model we characterised the root distribution and water uptake patterns of these two perennial crops during two cropping seasons under field conditions down to 2.5 m soil depth.ResultsBoth crops grew roots down to 2.0 m depth that were active in water uptake but alfalfa was deeper rooted than intermediate wheatgrass. All experimental methods concluded that alfalfa used more water from below 1.0 m depth than intermediate wheatgrass. However, simulations predicted that intermediate wheatgrass used more than 20 mm of water after anthesis from below 1 m soil depth. Simulations confirmed the advantage of deep roots in accessing deep soil water under drought.ConclusionsIn regions with high groundwater recharge, growing deep-rooted perennial crops have great potential to exploit deep soil water that is often left unused. However, the road to a profitable perennial grain crop is still long and breeding intermediate wheatgrass (Kernza®) cultivars for increased root growth at depth seems to be a worthy investment for the development of more drought tolerant cultivars.

Determining the nutrient content, energy, and in vitro true digestibility of some grass forage plants

The purpose of this study was to compare the chemical composition, metabolizable energy, net energy lactation, total digestible nutrient, in vitro digestion parameters, and relative feed quality of some grass forage plants growing naturally in the meadows and pastures of Erzurum province in Turkey. Orchardgrass (Dactylis glomerata), Variegated brome (Bromus variegatus), and Intermediate wheatgrass (Agropyron intermedium) were used as the research material. In this study, the metabolizable energy (ME) and net energy lactation (NEL) contents of the green grass crops forage plants were determined by in vitro gas production method, and their digestibility parameters and relative feed quality (RFQ) by the neutral detergent fiber (NDF) procedure using an Ankom Daisy incubator. As a result of the study, the differences between the forage plants were found to be statistically significant in terms of chemical composition, metabolizable energy, net energy lactation, true organic matter digestibility (TOMD) and RFQ (P<0.05). While the green intermediate wheatgrass was found to have the highest crude protein (CP) (19.56%), crude fat (CF) (3.06%), dry matter (DM) (9.14%), ME (8.82%), NEL (5.42%), and TOMD (97.75%); the green variegated brome was found to have the highest RFQ (149.79). The green orchardgrass was found to have the highest contents of neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL) with 66.23%, 34.14, and 8.52%, respectively. In conclusion, the green grass forage plants examined in this study can be used to eliminate the quality roughage deficit.