Browsing by Author "Khan, Qasim A."

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Crop rotation influences yield more than soil quality at a semiarid location
(Wiley, 2022-07) McVay, Kent; Khan, Qasim A.
Winter wheat (Triticum aestivum L.) is often rotated with a fallow in semiarid regions to conserve soil moisture and minimize crop failures. We hypothesized that direct seed systems coupled with intensified and more diverse crop rotations would produce an equivalent or greater annualized grain yield than a traditional winter wheat–fallow (WF) system. Furthermore, continuous cropping would lead to an accumulation of greater soil carbon than the traditional WF. A 6-yr study was conducted to evaluate crop rotations, which included pea (Pisum sativum L.), lentil (Lens culinaris Medik), lentil as a cover crop, spring wheat, or camelina [Camelina sativa (L.) Crantz] in rotation with winter wheat in 2- and 3-yr rotations. The results of this study averaged over 6 yr showed that increased cropping intensity produced an annualized yield equal to that of WF, provided that either a fallow or a cover crop rather than another grain crop was present prior to winter wheat. The soil quality indices showed particulate organic matter (POM) increased with rotations with greater cropping intensity (1.00 vs. 0.67), although the POM of these rotations was not different from that of WF.
Warm-Season Forage Options in Northern Dryland Regions
(2020-06) Carr, Patrick M.; Boss, Darrin L.; Chen, Chengci; Dafoe, Julia M.; Eberly, Jed O.; Fordyce, Simon; Hydner, Roger M.; Fryer, Heather K.; Lachowiec, Jennifer A.; Lamb, Peggy F.; McVay, Kent A.; Khan, Qasim A.; Miller, Perry R.; Miller, Zachariah J.; Torrion, Jessica A.
Rotating summer fallow with wheat (Triticum spp.) is done in dryland grain farming at upper latitudes to stabilize yields over time and to prevent crop failure. However, summer fallow is costly since weeds must be controlled and crops are not grown. Replacing summer fallow with grain crops can generate low economic returns. Previous research indicated that annual cool‐season forages can be substituted for summer fallow in dryland cropping systems. Our objective was to determine if annual warm‐season species were suited for forage production in monocultures and polycultures in the U.S. northern Great Plains. Dry matter (DM) production by 20 warm‐ and cool‐season crop monocultures and 4 polycultures was determined across six environments during 2016, and by 25 warm‐ and cool‐season crop monocultures and polycultures across four environments from 2016 through 2018. Maize (Zea mays L.) monoculture produced forage DM in amounts equal to, or greater than, those produced by other warm‐ and cool‐season crop treatments (P < 0.05). Maize DM production averaged 2.5 to 5.7 Mg ha−1, depending on the study and environment. Sorghum (Sorghum bicolor L.), foxtail millet [Setaria italica (L.) P. Beauv.] and sunflower (Helianthus annuus L.) also produced relatively large amounts of forage DM. Polycultures failed to produce more DM than monocultures consistently (P > 0.40). These results indicate that maize and other warm‐season crops are adapted for dryland forage production in cool regions at upper latitudes. Additional research is needed to determine the impacts of annual warm‐season forages on grain yield in a forage‐wheat crop sequence.