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Corn ( Zea mays ) biomass accumulation and nutrient uptake by the six-leaf collar (V6) growth stage are low, and therefore, synchronizing nutrient supply with crop demand could potentially minimize nutrient loss and improve nutrient use efficiency. Knowledge of corn's response to nutrient stress in the early growth stages could inform such nutrient management. Field studies were conducted to assess corn recovery from when no fertilizer application is made until the V6 growth stage, and thereafter, applying fertilizer rates as those in non-stressed conditions. The early season nutrient stress and non-stress conditions received the same amount of nutrients. As the availability of nutrients for plant uptake is largely dependent on soil moisture, corn recovery from the early season nutrient stress was assessed under different soil moisture regimes induced via irrigation scheduling at 50% and 80% field capacity under overhead and subsurface drip irrigation (SSDI) systems. Peanut ( Arachis hypogaea ) was the previous crop under all conditions, and the fields were under cereal rye ( Secale cereale ) cover crop prior to planting corn. At the V6 growth stage, the nutrient concentrations of the early season-stressed crops, except for copper, were above the minimum threshold of sufficiency ranges reported for corn. However, the crops showed poor growth, with biomass accumulation being reduced by over 50% compared to non-stressed crops. Also, the uptake of all nutrients was significantly lower under the early season nutrient stress conditions. The recovery of corn from the early season nutrient stress was low. Compared to non-stress conditions, the early season nutrient stress caused 1.58 Mg ha -1 to 3.4 Mg ha -1 yield reduction. The percent yield reduction under the SSDI system was 37.6-38.2% and that under the overhead irrigation system was 11.7-13%. The high yield reduction from the early season nutrient stress under the SSDI system was because of water stress conditions in the topsoil soil layer. The findings of the study suggest ample nutrient supply in the early season growth stage is critical for corn production, and thus, further studies are recommended to determine the optimum nutrient supply for corn at the initial growth stages., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Amissah, Ankomah, Lee, Perry, Washington, Porter, Virk, Bryant, Vellidis, Harris, Cabrera, Franklin, Diaz-Perez and Sintim.)

Growers rely on nutrient sufficiency ranges (NSRs) after plant tissue analysis to inform timely nutrient management decisions. The NSRs are typically established from survey studies across multiple locations, which could be confounded by several abiotic and biotic factors. We conducted field studies in 2020, 2021, and 2022 to validate the lower thresholds of the NSRs for corn ( Zea mays ) at the early growth stage as reported in the Southern Cooperative Series Bulletin #394. We induced various corn nutritional levels by making different nutrient application rates. If the NSRs are valid, samples within the same replication that satisfy the NSRs of all nutrients should have similar biomass accumulation. The results showed that the NSRs were not valid under the conditions tested. In total, 47.6% of the samples satisfied all the lower thresholds of the NSRs, and 25.4% of those samples had relative biomass <50%, with relative biomass even as low as 24.2% observed. Moreover, 9.6% of the total samples had P and Cu levels that failed to meet the lower threshold but still had relative biomass ≥75%. The findings highlight the sensitivity of corn to nutrient imbalance and the need to optimize nutrient diagnostic methods at the early growth stage.

Fibre-optic bronchoscopy is widely used to diagnose bronchial carcinoma. There is considerable variation in techniques for patient sedation, methods of obtaining samples and histopathological yield. We wished to examine variations in practice in different centres throughout Scotland and derive realistic audit standards for best clinical practice from these results. Diagnostic bronchoscopies from five centres were included. Patient details, grade of individual performing the test, endobronchial abnormalities, specimens taken and the histocytological yield were recorded. A patient satisfaction questionnaire was completed. One thousand eight hundred and two bronchoscopies were performed to look for bronchial carcinoma. Sedation and anaesthesia techniques varied considerably between centres. There were marked differences in patient satisfaction between centres. Nearly twice as many females as males would prefer not to have bronchoscopy repeated. Six hundred and fifty-eight carcinomas were confirmed by histocytology. Yield was unaffected by the grade of doctor performing bronchoscopy. Improving yield may be achieved by increasing the number of sampling techniques employed and changing the order in which specimens are taken (biopsies first and washings last). Eighty-seven percent of endoscopically visible tumours were confirmed histocytologically. There was a considerable variation in histological spectra between centres that may relate to differences in pathological interpretation rather than actual differences in case mix. Suggested audit standards are discussed. This study demonstrates the variety of techniques and also the levels of histocytological yield and patient satisfaction that can be achieved. Provisional standards of practice for this procedure have been agreed with a view to auditing performance against these. It is hoped that centres will adopt the methods that are shown to achieve the highest standards.