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An appropriate fertilization strategy is essential for improving micronutrient supply, crop nutrition, yield and quality. Comparative effects of different application strategies of micronutrient fertilizer were evaluated in two contrasting sites/soils (upper slope Chernozem and lower slope Solonetz) within a farm field located in the Brown soil zone of Saskatchewan, Canada. The study objective was to examine the impact of Cu, Zn, and B fertilizer application strategies on their mobility, bioavailability and fate in the soil as well as crop yield responses. The application strategies were broadcast, broadcast and incorporation, seed row banding, and foliar application of Cu, Zn, and B on wheat, pea, and canola, respectively. The study was laid out in a randomized complete block design (RCBD) with four treatment replicates for a specific crop and site. Crop biomass yields were not significantly influenced by micronutrient placement strategies at both sites. Pea tissue Zn concentration (35.2 mg Zn kg−1 grain and 5.15 mg Zn kg−1 straw) was increased by broadcast and incorporation of Zn sulfate on the Solonetz soil. Residual levels of soil extractable available Cu were increased significantly to 3.18 mg Cu kg−1 soil at Chernozem and 2.53 mg Cu kg−1 soil Solonetz site with the seed row banding of Cu sulfate. The PRS™-probe supply of Cu (1.84 µm Cu/cm2) and Zn (1.18 µm Zn/cm2) were significantly higher with broadcast application of corresponding micronutrient fertilizer in the Chernozem soil. Both the chemical and spectroscopic speciation revealed that carbonate associated Cu and Zn were dominant species that are likely to control the bioavailability of these micronutrients under field conditions. [ABSTRACT FROM AUTHOR]

This study evaluates the influence of phosphorus (P) fertilization (without and with added P fertilizer) and soil moisture (stress and no-stress) on efficacy, fate, and transformation of soil applied micronutrients such as copper (Cu), zinc (Zn), and Cu + Zn in a wheat and pea cropping sequence. Wheat was grown as first crop under controlled environment conditions in which micronutrient fertilizer treatments were applied, whereas pea was grown as following crop with recommended macronutrient fertilizers to understand the residual effects of micronutrient fertilization. The high-P fertilizer application and no-stress moisture condition produced the highest grain and straw yield of wheat. Without P fertilization, there were significant negative effects of a combined application of Cu and Zn on wheat yield in a Dark Gray Chernozem. Yield of the following pea crop did not show response to residual Cu and Zn. Micronutrient fertilization increased the Cu and Zn concentration in wheat and pea grain and straw and resulted in increased after-harvest availability and supply in soils. Apart from the increased concentration in labile fraction, a considerable amount of added Cu and Zn was occluded with organic matter and oxyhydroxide species, respectively. Molecular speciation analyses revealed that carbonate associated was the dominant form of Cu and Zn in the soils. Additional Cu species such as Cu-acetate and methoxide, and Zn species including Znsorbed montmorillonite species were identified. Insoluble Cu-phosphate and Zn-phosphate complexes were not identified by speciation analyses and do not appear to be a significant factor controlling Cu and Zn availability in these soils. [ABSTRACT FROM AUTHOR]

Five different cultivars each of wheat, pea, and canola were grown with and without copper (Cu), zinc (Zn), and boron (B) fertilization, respectively, in a greenhouse study to identify any crop cultivar and rhizosphere soil responses to micronutrient fertilization. The prairie agricultural surface soils (0–10 cm) used in the study were suspected to be micronutrient deficient according to soil extractable levels. Only durum wheat (CDC Fortitude) produced greater biomass from Cu fertilization compared to the other wheat cultivars. Cultivar dependent responses of pea and canola biomass yield to Zn and B fertilization were not significantly (P >.05) different. Boron concentration in whole plant canola tissue increased following fertilizer addition. Micronutrient fertilization increased concentrations and supply rates of available Cu, Zn, and B in post-harvest rhizosphere soil. Fertilizer Cu and Zn were distributed in labile soil solution-carbonate-exchangeable and oxyhydroxide fraction, whereas B was primarily found in the hot water-soluble fraction, specifically adsorbed and oxyhydroxide fractions. The composition of low molecular weight organic acids (formic, propionic, malic, and fumaric acid) in the rhizosphere soil varied among crops. Additionally, citric and tartaric acid were present in the pea and canola rhizosphere soils, respectively. The rhizosphere soil of durum wheat not fertilized with Cu contain higher levels of succinic acid compared to the other wheat cultivars. For pea and canola, there was no significant (P >.05) effect of cultivar on the amounts or forms of organic acids in the rhizosphere soils. [ABSTRACT FROM AUTHOR]

A polyhouse study was conducted to evaluate the relative effectiveness of different micronutrient fertilizer formulation and application methods on wheat, pea and canola, as indicated by yield response and fate of micronutrients in contrasting mineral soils. The underlying factors controlling micronutrient bioavailability in a soil–plant system were examined using chemical and spectroscopic speciation techniques. Application of Cu significantly improved grain and straw biomass yields of wheat on two of the five soils (Ukalta and Sceptre), of which the Ukalta soil was critically Cu deficient according to soil extraction with DTPA. The deficiency problem was corrected by either soil or foliar application of Cu fertilizers. There were no significant yield responses of pea to Zn fertilization on any of the five soils. For canola, soil placement of boric acid was effective in correcting the deficiency problem in Whitefox soil, while foliar application was not. Soil extractable Cu, Zn, and B concentration in post-harvest soils were increased with soil placement of fertilizers, indicating that following crops in rotation could benefit from this application method. The chemical and XANES spectroscopic speciation indicates that carbonate associated is the dominant form of Cu and Zn in prairie soils, where chemisorption to carbonates is likely the major process that determines the fate of added Cu and Zn fertilizer. [ABSTRACT FROM AUTHOR]