Ontario Corn and Soybean Micronutrients Knowledge Hub

BackgroundSalinity stress, an escalating concern in the realm of agriculture, significantly hampers crop productivity worldwide. In recent years, nano-fertilizers have been identified as an innovative and promising avenue for improving nutrient use efficiency and mitigating salt stress in plants. AimsThis study delves into the comparative efficacy of nano-fertilizers (Zn and Si) and their conventional sources in bolstering maize's resilience against salt stress. MethodsThe hydroponic experiment was conducted to test maize plants under salt stress along with Zn and Si nanoparticles (NPs) application. The analysis extends to their impacts on ionic homeostasis, specifically focusing on potassium and sodium concentrations, K/Na ratio, stomatal conductance, chlorophyll content, and the osmotic potential (OP) within the shoots and roots of maize. ResultsNanoparticles relatively helped plants better under stress, compared to their respective bulk mode of applications. Nano-Zn treatment considerably boosts the K+ concentration and enhanced K/Na ratio, as a key physiological trait in salt-resistant species, while nano-Si demonstrates a prominent role in modulating OP and limiting Na+ accumulation along with higher Zn and Si accumulation in plants. The salt tolerance index confirmed the contribution of these ionic and osmotic adjustments in helping maize plant against salt stress. ConclusionsOur findings confirm that the application of nutrients as nano-fertilizers, particularly nano-Zn, enhanced K/Na ratio and improved nutrient availability and uptake of the plant. Si nanoparticles are also attributed to better osmotic adjustment and facilitating water movement, thus highlighting the potential of nano-fertilizers in improving overall agricultural productivity and related environmental issues.

Genotype, severity of iron (Fe) deficiency, and interactions of Fe with Zn or Mn are important factors related to production of soybeans (Glycine max. L.) grown on high-pH, highly calcareous soils. We studied the within seed distribution (whole seed, seed coat, and embryo) of major and minor elements in 21 soybean genotypes (G)s characterized as susceptible (S), moderately resistant (MR), and resistant (R) to Fe deficiency based on planting seed [Fe]. Trials were grown at three locations (Loc) in northwest MN (Ada, Crookston, and Fisher) during 2003. Differences among Locs in within seed distribution of N, P, K, Ca, and Mg concentrations were generally quite small, although often statistically significant. Differences among genotypes involving macronutrient contents highlighted large differences among S, MR, and R genotypes. Zinc and Mn, but not Fe, concentrations varied markedly with location, whereas [Fe]s were considerably higher in genotypes categorized as more resistant to Fe deficiency. Seed size declined, whereas seed [Fe]s and contents increased as resistance to Fe deficiency increased. Seed coat [Fe]s were greater than embryo [Fe]s within each genotypic classification, whereas seed tissue [Fe] s were greater in R and MR genotypes than in S ones. As seed tissue Fe increased, Mn decreased, and their sum remained nearly constant. Planting seed [Fe] and published visual chlorosis scores were quite similar in their association with measures of resistance.

Climate change is forcing the search for innovative solutions to effectively reduce its harmful effects on food production. In addition, increasingly stringent regulations are being introduced in the European Union (the European Green Deal), mandating reductions in mineral fertilizer doses, which can reduce crop yields. One innovative technology could be soil fertilization and foliar application of Si-based fertilizers. A two-year field experiment (2023 and 2024), in commercial crop conditions in Kraski (52°2'42\" N, 18°54'6\" E), in Central Poland, studied the effect of differentiated soil fertilization and the foliar application of Si-based products on the yield and quality of maize grain at two levels of nitrogen/phosphorus/potassium (NPK) fertilization (100% and 50%). The soil fertilizer SiGSsup® (Si?200 g kg-1, Ca?181 g kg-1, Mg?46 g kg-1, and Mn?45 g kg-1) was applied to the soil at doses of 100, 300, and 500 kg ha-1, alone or with Barrier Si-Casup® (Si?336 g dm-3; Ca?207 g dm-3) foliar fertilizer (1 dm3 ha-1). The number of combinations assessed is 16. The effects were compared against the control treatment. The experiment evaluated plant physiological parameters, grain and dry matter yield, grain moisture content and quality (protein, fat, and starch content), and grain yield components. The highest grain yields were obtained with soil fertilization at a dose of 500 kg ha-1 (giving an increase of 17.5%), at a dose of 300 kg ha-1 plus foliar application (+16.4%), and at a dose of 500 kg ha-1 plus foliar application (+17.8%). The increase in grain yield in treatments with a half-rate of NPK was of a similar magnitude (on average, +11.9%) to the full rate (+12.6%) compared to the control treatments. Doubling the NPK rate contributed to an increase in grain yield of 7.8%. The applied fertilization had a significant and beneficial effect on the protein and fat content of the grain, while it reduced the starch content.

It has been assumed that zinc (Zn) fertilizers applied to maize simultaneously with amino acids (AA) at early stages of its growth may decrease the yield variability due to correcting its nutritional status during the 'critical window'. Two Zn carriers were evaluated (Zn-I-Zn chelate; Zn-II-Zn oxide); they were applied to maize at BBCH 14/15 with or without amino acids, based on two rates of nitrogen (80 and 160 kg N/ha). The precipitation deficiency in 2015 resulted in the grain yield decrease by 35% compared to 2014. An advantage of higher N rate was proved in 2014, whereas the influence of Zn and AA showed in 2015. In this year, the beneficial impact of Zn-oxide and AA combined application resulted in amelioration, at least partially, of the imbalance of certain macronutrient content (N, P, Mg) during the 'critical window'. These effects were revealed due to a boosted number of kernels in cob, and particularly higher thousand kernel weight. Consequently, the yield depression in 2015 was partly overcome. The results indicated that simultaneous application of Zn oxide and AA to maize at BBCH 14/15 corrected both its nutritional status during the 'critical window' and yield components, but had no effect on the yield itself.

A field experiment was conducted in 2008-2010 at the Experimental Station of the Faculty of Agricultural Sciences in Zamosc (50 degrees 42'N, 23 degrees 16'E), University of Life Sciences in Lublin. The aim of the study was to assess the impact of cropping method and weed control methods on the content of Cu, Zn, Fe and Mn in maize and on their uptake. Two cropping methods were studied - sole cropping and strip cropping (common bean, dent maize and spring barley in adjacent strips) and two weed control methods - mechanical and chemical. Strip cropping reduced Mn content in maize, did not significantly affect Zn content, and increased accumulation of Cu and Fe. The content and uptake of the elements by maize depended on the position of the row in the strip and on the adjacent plant species. Placement next to beans resulted in higher Fe and Zn content, while placement next to barley increased Cu content. The highest Mn content was noted in maize from the centre row. In general, micronutrient uptake by maize was lowest in the middle row. These results indicate that strip cropping can be an effective agricultural practise for plant biofortification.

Spent mushroom substrate (SMS) is a noxious byproduct of the mushroom industry. The aim of this work was to convert SMS into organicmineral micronutrient (Zn(II), Mn(II), and Cu(II)) fertilizer via biosorption and examine the effect of its application in field tests on maize compared to commercial reference micronutrient fertilizer. Crop yield and crop quality were assessed, and multielemental analysis of grains was conducted for the evaluation of the fertilization effect on maize grains and to assess bioavailability of nutrients from fertilizers. Grain yield for maize treated with micronutrients delivered with SMS was noticeably higher (11.5%) than the untreated group and the NPK (nitrogen, phosphorus, potassium) fertilizer treated only group (2.8%). Bioavailability (TF) of micronutrients from SMS were comparable with reference micronutrient fertilizer (7% Zn, 4% Mn, and 2.3% Cu). The new product has the potential to be used as a micronutrient fertilizer. Satisfactory results of grain yield (6.4 Mg ha-1), high content of micronutrients (Zn 1.6%, Mn 1.2%, and Cu 1.8%), and macronutrients (P 1.0%, S 3.1%, Ca 8.2%, and K 0.2%) were observed. The bioavailability suggests that enriched SMS could be a good alternative to fertilizers in the present market.

This Mosaic Crop Nutrition article summarizes University of Illinois research (Dr. Fred Below and Dr. Ross Bender, 20 trials over 3 years across 3 Illinois maturity zones) on soybean nutrition using MicroEssentials SZ fertilizer, which supplies P, K, and micronutrients including zinc and sulfur. The research is framed around correcting a common practice of fertilizing only for the preceding corn crop and under-fertilizing soybean, which can "mine" nutrients from the soil. Combined agronomic management (fertility, foliar disease/insect protection, variety selection, row spacing, seed treatments) was shown to increase soybean yield by about 10 bushels/acre, with roughly half attributable to proper nutrient application. The most detailed micronutrient discussed is boron: soybean requires about 0.3 oz B/acre for a 60-bushel crop, compared with only 1.8 oz B/acre needed for a 230-bushel corn crop ? noted as a meaningfully different B demand per bushel between the two crops. Boron is described as mobile in the soil (unlike P and K, which are held more tightly), so it can leach through the soil profile and needs ongoing attention even though total removal is low. The article notes soil testing should account for both macro- and micronutrients, and that foliar application can supplement but not replace adequate soil-available micronutrient levels. No specific soil-test thresholds, deficiency symptoms, or application rates/timing for zinc or other micronutrients are given for soybean or corn; the piece is a research-summary/marketing article rather than a technical guideline, emphasizing balanced P/K/micronutrient management and variety/maturity selection as complementary yield levers alongside boron nutrition.

The Tri-State Fertilizer Recommendations (Bulletin 974, Ohio State/Purdue/Michigan State, corn/soybean/wheat/alfalfa) devotes a dedicated micronutrients section to corn and soybean. Deficiencies of boron, copper, manganese, molybdenum, and zinc can occur regionally; chlorine, molybdenum, and iron deficiencies are rare. Deficiency-prone conditions (Table 30): Cu on acid peats/mucks (pH<5.3) affecting corn/wheat/oats; Mn on peats/mucks (pH>5.8) and high-pH lakebed soils affecting soybean/corn/wheat/sugar beets; Mo on acid prairie soils affecting soybean; Zn on peats, mucks, and mineral soils with pH>6.5 affecting corn and soybean. Diagnosis relies on combining soil tests (0.1N HCl for Mn/Zn, 1.0N HCl for Cu, though Mehlich-3 is more commonly used regionally though not fully calibrated) with plant tissue analysis, since soil micronutrient tests are less reliable than for macronutrients. A synthesis of 194 Ohio trials (33 corn, 144 soybean, 17 alfalfa) found yield responses to micronutrient fertilization were rare ? only Mn applied to soybean showed a response, in 9 of 144 trials. Reported adequate tissue ranges (ppm) include corn ear leaf at silking: B 10-44, Cu 6-19, Fe 87-448, Mn 16-86, Zn 14-45; soybean upper trifoliate at flowering: B 45-100, Cu 6-18, Fe 83-384, Mn 22-124, Zn 18-76. Recommended rates (Table 33): Mn = (6.2×soil pH) ? (0.35×0.1N HCl-extractable Mn ppm) ? 36 lb/acre (mineral soils); Zn = (5.0×soil pH) ? (0.4×0.1N HCl-extractable Zn ppm) ? 32 lb/acre; Cu = 6.3 ? (0.3×1.0N HCl-extractable Cu ppm) lb/acre (organic soils). Broadcast Zn of 5-10 lb/acre can correct deficiency; broadcast Mn is discouraged due to soil fixation, so foliar Mn is preferred. Boron is not recommended for corn/soybean (only for alfalfa/clover at 1-2 lb/acre). Molybdenum for soybean: ½ oz sodium molybdate/bushel seed treatment or 2 oz/acre foliar spray on acid soils; high Mo can be toxic to livestock.

Foliar nutrient concentrations vary during the day. Field research was conducted to quantify and better understand this variation in corn (Zea mays L.) and soybean (Glycine max L. Merr.) with foliar sampling during the vegetative and reproductive stages. Time of day effects occurred inconsistently across nutrients. Nitrogen (N), manganese (Mn), iron (Fe), and zinc (Zn) foliar concentrations were generally high early in the day. Phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S) foliar concentrations varied inconsistently with time of day, while concentrations of boron (B) in both crops and copper (Cu) in corn were not affected. Limiting foliar sampling to after 10:00 AM reduced the variation for soybean but not for corn. Interpretation by Diagnosis and Recommendation Integrated System (DRIS) did not reduce the time of day effect. The variation caused by time of day, along with other causes, affects confidence in interpretation of foliar results suggesting use of the information with either additional foliar sampling or soil testing in making nutrient management decisions.

Iron deficiency in human diet is a serious problem leading, among others, to the development of iron-dependent anaemia, which affects 1.8 billion people worldwide. Biofortification of crop plants, including edible sprouts, is a promising strategy for combating dietary deficiencies. The aim of the present study is the evaluation of the effect of seeds imbibition in FeCl2 solution with Fe at the concentrations of 100 and 500 mgL(-1) on the seeds germination, growth of the seedlings, their antioxidant activity and the level of total phenolics and flavonoids. The results show that pre-treatment of seeds with Fe leads to increased accumulation of this metal in the germinated seedlings. In addition, it affects germs antioxidant activity and the level of flavonoids. On the other hand, seeds imbibition in FeCl2 had no effect on the germination rate, growth of seedlings or total phenolic content (TPC). The results indicate that seeds imbibition in Fe solution is a promising strategy for obtaining Fe-enriched soybean sprouts.