Hydroponics, a soilless cultivation technique using nutrient solutions under controlled conditions, is used for growing vegetables, high-value crops, and flowers. It produces significantly higher yields compared to conventional agriculture despite its higher energy consumption. The success of a hydroponic system relies on the composition of the nutrient solution, which contains all the essential mineral elements necessary for optimal plant growth and high yield. This review delves into the discussion of enhancing nutrient solution management strategies across different hydroponic systems. The aim of this review is to discuss various techniques for monitoring nutrient solutions in order to improve nutrient use efficiency (NUE) and water use efficiency (WUE). The conventional approach of monitoring the hydroponic nutrient solution using electrical conductivity measurement may not provide precise information about ion concentrations, potentially resulting in poor yields or excessive fertilizer usage. To overcome these limitations, alternative management strategies have been developed to enable more accurate monitoring and efficient management. One such strategy is the nitrogen-based approach, where nitrogen concentration becomes the primary controlled element in the nutrient solution and leads to WUE and NUE development by prolonging nutrient solution recirculation. Furthermore, various methods have been devised to improve nutrient solution strategies. These include using ion-selective electrodes to measure individual ions in the hydroponic nutrient solution, using sensors to monitor substrate moisture content, estimating water requirements, and implementing programmed nutrient addition methods. In addition to introducing different management techniques to optimize hydroponic performance, this review provides a better understanding of hydroponic systems.

Herbicide resistance in western Canada has increased interest in alternative weed management strategies. Physical impact mills, a form of harvest weed seed control, have been identified as a strategy that may be well suited for Canadian use. The efficacy of the Harrington Seed Destructor, a physical impact mill, was evaluated in 20 producer fields in Alberta on a wide spectrum of weed species over 3 years. Significant differences in weed densities between the physical impact mill treatment and the regular harvest densities were few; however, some population density reductions were observed. Measurable reductions in weed densities may have been limited by the short timeframe of the experiment, the high initial densities of the weeds, or the targeted weed species having dormancy or longer term seedbanks. Additionally, identified knowledge gaps on how best to optimize physical impact mill efficacy may have reduced the efficacy of the physical impact mill in this study. This study showed no conclusive evidence for the efficacy of a physical impact mill on tested weed species under field conditions. However, it did provide a number of important considerations for future studies.

Harvest weed seed control (HWSC), an evolving strategy in weed management, is highly effective for the control of a variety of weed species in North American cropping systems. Previous devices for weed seed devitalization at harvest have been limited to tow behind and integrated combine systems. The potato vine crusher (PVC) is a harvester-mounted set of rollers originally designed for crushing and control of Ostrinia nubilalis (Hübner) larvae during potato (Solanum tuberosum L.) harvest. To evaluate the potential of the PVC for HWSC, we conducted stationary testing of spring tension and roller speed settings to maximize devitalization of lambsquarters (Chenopodium album L.), the most problematic weed species in Canadian potato production. In addition, we evaluated the efficacy of the PVC for the devitalization of several pernicious weed species under controlled conditions and during a simulated harvest. Increasing PVC spring tension reduced the devitalization of lambsquarters seed, whereas roller speed had minimal effect. In contrast, maximized spring tension and minimized roller speed reduced lambsquarters emergence (53%) in soil. Hypocotyl and radicle elongation was observed from lambsquarters seed fragments under controlled conditions, potentially contributing to increased control in soil through fatal germination. High levels of seed devitalization (65%–94%) were observed for all species under controlled conditions. During simulated harvest, control of large weed seeds (50%–63%) was observed, whereas smaller seeds were not impacted, signifying the importance of seed size for PVC efficacy. These studies demonstrate the PVC as a promising new tool for HWSC in Canadian potato production systems.

Glyphosate-resistant giant ragweed (Ambrosia trifida L.) was first identified in Canada in 2008. Although early studies attributed resistance in this species solely to non-target site mechanisms, the presence of a proline (P) to serine (S) mutation at position 106 of EPSPS2 in common and giant ragweed has recently been reported. The objective of this research was (i) to determine whether a P106S mutation is present in historical samples of giant ragweed seed collected from the site of the first report of glyphosate resistance, and (ii) to determine the frequency and distribution of P106S in resistant and susceptible biotypes collected as part of historical surveys throughout southwestern Ontario.

Fusarium head blight (FHB) resistance in wheat is often associated with undesirable agronomic traits such as tall plant height and a propensity for lodging. Plant height in wheat is genetically controlled by some semi-dwarfing alleles that alter the plant's sensitivity to gibberellins (GAs). The presence of semi-dwarfing alleles increases the frequency of anther retention, which may contribute to FHB susceptibility by providing an initiation site for infection. The application of plant growth regulators (PGRs) may enable farmers to grow the most resistant cultivars while controlling plant height to minimize lodging risk. In this study, five spring wheat cultivars that differed in level of FHB resistance, height, and semi-dwarfing alleles were tested to determine the effect of PGRs, specifically Manipulator™ and Ethrel™, on plant height, anther retention, and FHB resistance level and the interactions between them in Winnipeg and Carman, Manitoba in 2019 and 2020. Combined field results showed that Ethrel™ significantly reduced plant height. Both PGRs did not affect the anther retention or FHB resistance levels of the tested cultivars under dry conditions. There were significant interactions between variables, but they were relatively small compared to the main treatment and cultivars. Based on the results of this study, producers could benefit from the higher levels of FHB resistance often associated with tall cultivars and use PGRs to manage plant height and lodging without increased risk of FHB.

Granular urea fertilizer applied at planting is prone to nitrogen (N) losses in certain environments. Enhanced efficiency fertilizers (EEFs) are developed to mitigate losses and optimize plant uptake. To determine the benefits of EEFs in grain yield and quality enhancement in Canada Western Red Spring (CWRS) wheat, an experiment was conducted from 2019 to 2022 at eight sites in Alberta and Saskatchewan, Canada. The effects of five N sources [urea; urea + urease inhibitor, N-(n-butyl)thiophosphoric triamide (NBPT); urea + nitrification inhibitor, nitrapyrin; urea + dual-inhibitor, NBPT + dicyandiamide; and polymer-coated urea, ESN^® (Environmentally Smart Nitrogen^®)] and four N rates (60, 120, 180, and 240 kg N ha⁻¹) on CWRS wheat production were examined. Results indicated that N source affected grain yield in Dark Brown Chernozem soils but not in Black Chernozem or Dark Grey Luvisol soils. In Dark Brown Chernozem soils, a dual inhibitor increased grain yield by 3.1% and 3.9% relative to urea and polymer-coated urea, respectively, while all other EEFs attained similar results. The use of a dual inhibitor EEF led to greater net returns compared to urea and polymer-coated urea in the Dark Brown Chernozem soils. Grain protein concentration increased linearly with increasing N rate from 60 to 240 kg N ha⁻¹. Generally, a rate of 120 kg N ha⁻¹ was optimal for CWRS wheat grown in Canadian prairie conditions when coupled with EEFs, particularly a dual inhibitor, and grain yield and protein were often responsive.

Sesquiterpene lactone artemisinin is one of the main agents used to treat malaria. Artemisinin is produced in the glandular secretory trichomes (GSTs) of Artemisia annua. The plant hormones and metabolic pathways regulate the artemisinin content of A. annua. It was possible to examine the functions of auxin, an important plant hormone, in the development of GSTs in A. annua by enhancing the expression of iaaM, which encodes a tryptophan monooxygenase involved in the biosynthesis of auxin. Additionally, the effects of co-overexpression of aldehyde dehydrogenase 1 (ALDH1), P450 monooxygenase (CYP71AV1), and iaaM on the density, length, and width of GSTs and the contents of artemisinin were further investigated. Results indicated that overexpression of iaaM might increase the density, length, and width of GSTs by enhancing auxin biosynthesis. This study also proved the key regulatory role of ALDH1 in the biosynthesis of artemisinin. Moreover, co-overexpression of ALDH1, CYP71AV1, and iaaM successfully increased the density, length, and width of GSTs and improved the artemisinin content in A. annua. Therefore, we established a theoretical basis for modifying artemisinin accumulation in this study by regulating the expression of auxin and artemisinin synthesis-related genes using a metabolic engineering method.

Studies documenting the consequences of harvest traffic in alfalfa production have addressed soil and plant growth parameters. One response was larger leaf/stem ratios in plants that were trafficked, which suggests higher quality. To fully understand how harvest traffic affects alfalfa quality a need for further analysis is warranted. Our objectives were to quantify differences in plant quality between trafficked and non-trafficked plants through 4 years of alfalfa production and to determine when these differences occur. The experimental units were furrow-irrigated raised beds with four harvests per year in Youngston clay loam soil in Fruita, Colorado. A John Deere 2280 swather and a John Deere 2955 tractor, driven over the alfalfa 7 days after swathing, were used to create four traffic treatments; plants that were never trafficked, plants trafficked only by the swather, plants trafficked only by the tractor, and plants trafficked by both the swather and the tractor. Quality was determined by measuring relative feed value, acid detergent fiber, neutral detergent fiber, and crude protein using near infrared reflectance spectroscopy. Alfalfa trafficked by the tractor had increased quality throughout the 4 years of production.

Sequential mesotrione applications of 72 g a.i. ha⁻¹ gave similar control of narrow-leaved goldenrod as sequential applications of 144 g a.i. ha⁻¹. This use pattern is recommended for narrow-leaved goldenrod management in lowbush blueberry. Early POST tolpyralate applications exhibited good crop tolerance and could be considered as part of a sequential herbicide program for lowbush blueberry.