Browsing by Author "Dhillon, Jagmandeep S."

Now showing 1 - 5 of 5
  • Thumbnail Image
    Item
    Effect of winter wheat cultivar on grain yield trend under different nitrogen management
    (Agrosystems, Geosciences & Environment,, 2020) Aula, Lawrence; Omara, Peter; Eickhoff, Elizabeth; Oyebiyi, Fikayo; Dhillon, Jagmandeep S.; Raun, William R.
    In many developing countries, crop production is achieved with little or no application of fertilizer N. Understanding grain yield trends as new winter wheat cultivars (Triticum aestivum L.) are released and grown under different N management is important for crop yield improvement. This study evaluated grain yield trends of winter wheat cultivars over time in a crop production system with and without N application. Yield data was obtained from two long-term experiments; 502 (E502) and 222 (E222) between 1969 and 2018. Results showed a mean annual grain yield increase of 12 and 30 kg ha–1 yr–1 as new cultivars were released and grown under adequate N management in E222 and E502, respectively. However, without N application, yield declined annually by 2.4 kg ha–1 yr–1 in E222 and increased marginally by 0.6 kg ha–1 yr–1 in E502. Nonetheless, the yield increase or decrease was only significant for E502 at 112 kg N ha–1 (r2 = .145; p = .01) and its slope was significantly different from that of control treatment (p = .02). In both experiments, yield was significantly influenced by cultivar and N interaction (p < .01), an indication that yield changed according to the level of N applied. In general, when N was applied, grain yields were high as well. New cultivars released over time improved grain yield with adequate N management.
  • Thumbnail Image
    Item
    Influence of No-Tillage on Soil Organic Carbon, Total Soil Nitrogen, and Winter Wheat (Triticum aestivum L.) Grain Yield
    (International Journal of Agronomy, 2019) Omara, Peter; Aula, Lawrence; Eickhoff, Elizabeth M.; Dhillon, Jagmandeep S.; Lynch, Tyler; Wehmeyer, Gwendolyn B.; Raun, William
    No-tillage (NT) can improve soil properties and crop yield. However, there are contrasting reports on its benefits compared to conventional tillage (CT). Dataset (2003–2018) from long-term continuous winter wheat (Triticum aestivum L.) experiments 222 (E222) at Stillwater and 502 (E502) at Lahoma in Oklahoma, USA, established in 1969 and 1970, respectively, was used. Both experiments were managed under CTuntil 2010 and changed to NT in 2011. In each tillage system, treatments included nitrogen (N) rates at E222 (0, 45, 90, and 135 kg·N·ha− 1) and E502 (0, 22.5, 45, 67, 90, and 112 kg·N·ha− 1). (e objective was to determine the change in wheat grain yield, soil organic carbon (SOC), and total soil nitrogen (TSN) associated with the change to NT. Grain yield was recorded, and postharvest soil samples taken from 0–15 cm were analyzed for TSN and SOC. Average TSN and SOC under NT were significantly above those under CT at both locations while grain yield differences were inconsistent. Under both tillage systems, grain yield, TSN, and SOC increased with N rates. At E222, grain yield, TSN, and SOC under NT were 23%, 17%, and 29%, respectively, more than recorded under CT. At E502, grain yield was lower under NT than CT by 14% while TSN and SOC were higher by 11% and 13%, respectively. Averaged over experimental locations, wheat grain yield, TSN, and SOC were 5%, 14%, and 21%, respectively, higher under NTcompared to CT. (erefore, NTpositively influenced grain yield, TSN, and SOC and is likely a sustainable long-term strategy for improving soil quality and crop productivity in a continuous monocropping system.
  • Thumbnail Image
    Item
    No-tillage Improves Winter Wheat (Triticum Aestivum L.) Grain Nitrogen Use Efficiency
    (Communications in Soil Science and Plant Analysis,, 2019) Omara, Peter; Aula, Lawrence; Oyebiyi, Fikayo; Nambi, Eva; Dhillon, Jagmandeep S.; Carpenter, Jonathan; Raun, William R
    Tillage practices are among the factors that affect soil quality as well as use efficiency of fertilizer nitrogen (N). Data consisting of 24-site-years from two long-term experiments 222 (E222) located in Stillwater and 502 (E502) located in Lahoma, Oklahoma were used in this study. Treatments included pre-plant N rates of 0, 45, 90, and 135 kg N ha−1 at E222 and 0, 22.5, 45, 67, 90 and 112 kg N ha−1 at E502. The objective was to evaluate the influence of no-tillage (NT) on grain N uptake and N use efficiency (NUE) of winter wheat (Triticum aestivum L.) relative to conventional tillage (CT). Generally, results indicated significantly higher grain N uptake and NUE under NT relative to CT. However, single-degree-of-freedom contrast at individual N rate indicated inconsistency in grain N uptake and NUE between experimental locations. Under both tillage practices, grain N uptake increased with N rate while NUE decreased as N rate increased. Overall, NUE and grain N uptake was 23% and 7.5% higher under NT compared to CT, respectively. Therefore, winter wheat farmers in the United States Central Great Plains currently practicing CT could improve the efficiency of the surface-applied fertilizer N and farm profitability by adopting NT.
  • Thumbnail Image
    Item
    Variability in Winter Wheat (Triticum aestivum L.) Grain Yield Response to Nitrogen Fertilization in Long-Term Experiments
    (Communications in Soil Science and Plant Analysis, 2020) Omara, Peter; Aula, Lawrence; Dhillon, Jagmandeep S.; Oyebiyi, Fikayo; Eickhoff, Elizabeth M.; Nambi, Eva; Fornah, Alimamy; Carpenter, Jonathan; Raun, William
    Crop nitrogen (N) use is always affected by the variability in production environment. Dataset (2001 to 2014) from long-term winter wheat (Triticum aestivum L.) experiments at Lahoma and Stillwater, Oklahoma was used. Both experiments have a randomized complete block design with four replications, and fertilizer N was applied as urea pre-plant. Responsiveness of grain yield to maximum fertilizer N rate (112 kg ha−1 – Lahoma; 135 kg ha−1 – Stillwater) was compared with that from check plot (0 kg ha−1). The objective was to determine the relative influence of environment, management, and variety on winter wheat grain yield. The combined analysis of variance indicated that the main effect of year, treatment, location, and variety accounted for 29.3%, 21.2%, 3.1%, and 22.6%, respectively of the variance terms. Over the study period, the nonresponsiveness of winter wheat to fertilizer N accounted for 29% and 23% of grain yield at Lahoma and Stillwater, respectively where yield at maximum N rate did not significantly differ from check plot. This highlights the importance of random changes in a crop production environment and its influence in dictating the response to applied N fertilizer. Nitrogen fertilizer losses could be reduced by adopting in-season variable N application techniques.
  • Thumbnail Image
    Item
    World Sulfur Use Efficiency for Cereal Crops
    (Agronomy Journal, 2019) Aula, Lawrence; Dhillon, Jagmandeep S.; Omara, Peter; Wehmeyer, Gwendolyn B.; Freeman, Kyle W.; Raun, William R.
    Sulfur (S) is an essential plant nutrient needed for higher crop yields and improved nutritional value. In recent decades, the occurrence of S deficiency has increased and fertilizer S use may steadily increase. This may lead to inefficient crop utilization of S and result into negative footprints on the environment. The objective of this work was to estimate world fertilizer sulfur use efficiency (SUE) for major cereal crops grown around the world. A 10-yr data set (2005–2014) was obtained from the Food and Agriculture Organization, the US Geological Survey, and an array of other published research articles. Statistical analysis was performed using MS Excel to obtain total area for world and cereal crops, grain yield, and fertilizer S applied. The difference method [(Total grain S – grain S derived from the soil)/S applied] was used to compute world SUE. Cereal crops included in this study were barley (Hordeum vulgare L.), maize (Zea mays L.), rice (Oryza sativa L.), millet (Pennisetum glaucum L.), wheat (Triticum aestivum L.), sorghum (Sorghum bicolor L.), rye (Secale cereale L.), and oat (Avena sativa L.). Cereal production increased from 2669 M Mg in 2005 to 3346 M Mg in 2014. Sulfur use efficiency for cereal crops was estimated to be 18%. This low SUE may be attributable to S leaching from the soil profile, immobilization, retention in residues, and adsorption. As increased quantities of fertilizer S are likely to be applied in future to meet the ever-growing demand for food, SUE could decline below 18%.