Vesh R Thapa, Jianxin Sun, Katja Koehler-Cole, David Scoby, Geng Frank Bai, Yufeng Ge, Hongfeng Yu, Andrea Basche

Abstract

This study explores the variability in aboveground biomass (AGB) production of winter cover crops (CCs) across Nebraska, focusing on wheat (Triticum aestivum L.), rye (Secale cereale L.), triticale (Triticale spp.), and canola (Brassica napus L.). Nebraska’s wide precipitation gradient, spanning from semi-humid to semi-arid conditions, poses challenges in setting realistic biomass goals for the winter growing season. A literature review of 18 studies revealed significant variation in AGB production, averaging 2105 ± 1670 kg ha-1 across species and locations. Specifically, wheat, rye, triticale, and canola produced biomass ranging from 110 to 6710, 190 to 6310, 750 to 7160, and 100 to 2200 kg ha-1, respectively. The Agricultural Production Systems sIMulator (APSIM) model was employed to simulate AGB production, leaf area index, and plant height based on data from a unique phenotyping experiment. The model demonstrated moderate to high accuracy across species and years, aligning with the ranges found in the literature review. However, its performance was less reliable under extreme conditions, such as winter-kill events. The model predicted AGB production with a relative root mean square error (RRMSE) of 20% for wheat, 18% for rye, 14% for triticale, and 27% for canola. Early planting (mid-September) and late termination (early-May) boosted AGB yields by 158% for wheat, 112% for rye, 131% for triticale, and 247% for canola compared to shorter growing intervals (early-October to mid-April). The concept of the “CC growth gap (βg),” was introduced, showing biomass losses during shorter growing intervals, ranging from 21% to 53% for wheat, 27% to 67% for rye, 23% to 58% for triticale, and 20% to 43% for canola. This study underscores the critical influence of growing interval, regional climate, soil type, and species selection on AGB production, highlighting the importance of intentional planting and termination timing to optimize AGB yields in diverse environmental conditions.

Bibtex

@inproceedings{thapa2024estimating,
  title={Estimating the Winter Biomass Potential of Four Cover Crop Species: Wheat, Rye, Triticale, and Canola},
  author={Thapa, Vesh R and Sun, Jianxin and Koehler-Cole, Katja and Scoby, David and Bai, Geng Frank and Ge, Yufeng and Yu, Hongfeng and Basche, Andrea},
  booktitle={ASA, CSSA, SSSA International Annual Meeting},
  year={2024},
  organization={ASA-CSSA-SSSA}
}