Browsing by Author "Jones, Clain"

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Lentil nitrogen fixation response to fertilizer and inoculant in the northern Great Plains
(Wiley, 2023-08) Baber, Kaleb; Jones, Clain; Miller, Perry; Lamb, Peggy; Atencio, Sydney
Lentil (Lens culinaris Medikus) production in the semiarid northern Great Plains of the United States has increased dramatically over the past two decades. Lentil in rotation provides agroecosystem benefits of more efficient water use, pest cycle disruption, and biological nitrogen (N) fixation. Increasing N fixation could alleviate soil acidification and groundwater impairment, decrease N fertilizer costs, and increase lentil seed yield. Despite widespread farmer adoption of lentil in the region, little is known about the benefits of fertilizer or inoculant type on N fixation. The aim of this study was to determine how nutrients (potassium (K), sulfur (S), and foliar-applied micronutrients) and rhizobial inoculant types (seed-coat powder and granular) influence N fixation of lentil. The study was conducted at two field sites in Montana from 2019 to 2021. Fixed N amounts were calculated using both an N difference approach and 15N natural abundance method. N fixation was highly responsive to climatic conditions and soil characteristics. The amount of N fixed did not respond to K fertilization, likely because soil test K levels were sufficient. In a moderately dry year at a site with low soil sulfate-S, fertilizer application of 5.6 kg S ha−1 increased N fixed by 40%. Inoculated lentil fixed more N than uninoculated lentil in two site-years, but there were no differences in N fixed between inoculant types. Inoculation response was not related to field cropping histories with legumes. The study shows that S fertilization and rhizobial inoculation have potential to increase lentil N fixation amounts in the northern Great Plains.
Nitrogen fixation among pea and lentil varieties in the Northern Great Plains
(Wiley, 2023-08) Baber, Kaleb; Jones, Clain; McPhee, Kevin; Miller, Perry R.; Lamb, Peggy
Pulse crops, including lentil (Lens culinaris Medik.) and pea (Pisum sativum L.), can improve the sustainability of Northern Great Plains cropping systems, largely through biological N fixation. Greater N fixation amounts can help producers to increase yield while decreasing N fertilizer inputs for the following crop. There may be potential to breed greater N-fixing pulse varieties, yet little is known about varietal differences in N fixation. Nitrogen fixation of pea and lentil varieties was quantified at two sites in Montana from 2019 to 2021 using an N difference approach and the 15N natural abundance method. Riveland and CDC Richlea were frequently high N-fixing lentil varieties, both fixing ca. 130 kg N ha−1 in the site-year with the most favorable growing conditions. No pea variety had consistently greater N fixation than others, despite N fixation ranging from 88 to 135 kg N ha−1 in one site-year among varieties. Nitrogen fixation by lentil had an inverse relationship with days to flowering but was not correlated with days to maturity. Nitrogen fixation by pea was positively correlated with days to maturity but was not correlated with days to flowering. Breeding lentil and pea for high N fixation by selecting high N-fixing varieties is likely difficult, as varieties performed differently under variable environmental conditions. Breeding efforts based on traits, such as days to flowering, could be more successful. There were more positive correlations between N fixation parameters and seed yield for pea than for lentil, suggesting that breeding for greater yields could increase N fixation for pea but not lentil.
Sentinel-2-based predictions of soil depth to inform water and nutrient retention strategies in dryland wheat
(Elsevier BV, 2023-11) Fordyce, Simon I.; Carr, Patrick M.; Jones, Clain; Eberly, Jed O.; Sigler, W. Adam; Ewing, Stephanie; Powell, Scott L.
The thickness or depth of fine-textured soil (zf) dominates water storage capacity and exerts a control on nutrient leaching in semi-arid agroecosystems. At small pixel sizes (< 1 m; ‘fine resolution’), the normalized difference vegetation index (NDVI) of cereal crops during senescence (Zadoks Growth Stages [ZGS] 90–93) offers a promising alternative to destructive sampling of zf using soil pits. However, it is unclear whether correlations between zf and NDVI exist (a) at larger pixel sizes (1–10 m; ‘intermediate resolution’) and (b) across field boundaries. The relationship of zf to NDVI of wheat (Triticum aestivum L.) was tested using images from a combination of multispectral sensors and fields in central Montana. NDVI was derived for one field using sensors of fine and intermediate spatial resolution and for three fields using intermediate resolution sensors only. Among images acquired during crop senescence, zf was correlated with NDVI (p < 0.05) independent of sensor (p = 0.22) and field (p = 0.94). The zf relationship to NDVI was highly dependent on acquisition day (p < 0.05), but only when pre-senescence (ZGS ≤ 89) images were included in the analysis. Results indicate that cereal crop NDVI of intermediate resolution can be used to characterize zf across field boundaries if image acquisition occurs during crop senescence. Based on these findings, an empirical index was derived from multi-temporal Sentinel-2 imagery to estimate zf on fields in and beyond the study area.