Mineral phosphorus (P) fertilizers support high crop yields and contribute to feeding the teeming global population. However, complex edaphic processes cause P to be immobilized in soil, hampering its timely and sufficient availability for uptake by plants. The resultant low use efficiency of current water-soluble P fertilizers creates significant environmental and human health problems. Current practices to increase P use efficiency have been inadequate to curtail these problems. We advocate for the understanding of plant physiological processes, such as physiological P requirement, storage of excess P as phytate, and plant uptake mechanisms, to identify novel ways of designing and delivering P fertilizers to plants for improved uptake. We note the importance and implications of the contrasting role of micronutrients such as zinc and iron in stimulating P availability under low soil P content, while inhibiting P uptake under high P fertilization; this could provide an avenue for managing P for plant use under different P fertilization regimes. We argue that the improvement of the nutritional value of crops, especially cereals, through reduced phytic acid and increased zinc and iron contents should be among the most important drivers toward the development of innovative fertilizer products and fertilization technologies. In this paper, we present various pathways in support of this argument. Retuning P fertilizer products and application strategies will contribute to fighting hunger and micronutrient deficiencies in humans. Moreover, direct soil P losses will be reduced as a result of improved P absorption by plants.

/pdf/exploring-phosphorus-fertilizers-and-fertilization-372sqs27km.pdf

Exploring phosphorus fertilizers and fertilization strategies for improved human and environmental health

Micronutrients are essential mineral elements required for both plant and human development. However, micronutrients are often lacking in soils, crop, and food. Micronutrients are therefore used as fertilizer to increase crop productivity, especially when the application of conventional NPK fertilizers is not efficient. Here, we review the application of micronutrients in crop production. Reports show that micronutrients enhance crop nutritional quality, crop yield, biomass production, and resiliency to drought, pest, and diseases. These positive effects range from 10 to 70 %, dependent on the micronutrient, and occur with or without NPK fertilization. We discuss the uptake by plants of micronutrients as nanosize particulate materials, relative to conventional uptake of ionic nutrients. We also show that packaging of micronutrients as nanoparticles could have more profound effects on crop responses and fertilizer use efficiency, compared to conventional salts or bulk oxides.

/pdf/fortification-of-micronutrients-for-efficient-agronomic-4b4lvcn988.pdf

Fortification of micronutrients for efficient agronomic production: a review

Zinc oxide nanoparticles alleviate drought-induced alterations in sorghum performance, nutrient acquisition, and grain fortification

Nanoparticles are used in a variety of products, including fertilizer-nutrients and agro-pesticides. However, due to heightened reactivity of nano-scale materials, the effects of nanoparticle nutrients on crops can be more dramatic when compared to non nano-scale nutrients. This study evaluated the effect of nano manganese-(Mn) on wheat yield and nutrient acquisition, relative to bulk and ionic-Mn. Wheat was exposed to the Mn types in soil (6 mg/kg/plant), and nano-Mn was repeated in foliar application. Plant growth, grain yield, nutrient acquisition, and residual soil nutrients were assessed. When compared to the control, all Mn types significantly (p < 0.05) reduced shoot N by 9–18%. However, nano-Mn in soil exhibited other subtle effects on nutrient acquisition that were different from ionic or bulk-Mn, including reductions in shoot Mn (25%), P (33%), and K (7%) contents, and increase (30%) in soil residual nitrate-N. Despite lowering shoot Mn, nano-Mn resulted in a higher grain Mn translocation efficiency (22%), as compared to salt-Mn (20%), bulk-Mn (21%), and control (16%). When compared to soil, foliar exposure to nano-Mn exhibited significant differences: greater shoot (37%) and grain (12%) Mn contents; less (40%) soil nitrate-N; and, more soil (17%) and shoot (43%) P. These findings indicate that exposure to nano-scale Mn in soil could affect plants in subtle ways, differing from bulk or ionic-Mn, suggesting caution in its use in agriculture. Applying nano Mn as a foliar treatment could enable greater control on plant responses.

https://www.mdpi.com/2073-4395/8/9/158/pdf

Effects of Manganese Nanoparticle Exposure on Nutrient Acquisition in Wheat (Triticum aestivum L.)

Wheat (Triticum aestivum L.) is one of the main foods globally. Nutrition problems associated with Zinc and Iron deficiency affect more than two billion individuals. Biofortification is a strategy believed to be sustainable, economical and easily implemented. This study evaluated the effect of combined Zn and Fe applied as foliar fertilizer to winter wheat on grain yield, quality, Zn and Fe concentration in the grains. Results showed that treatments containing high Fe increased the yield. Grain crude fat content remained unaffected. Crude fiber was enhanced up to three-fold by 60% Zn + 40% Fe5.5 (5.5 kg ha−1 of 60% Zn + 40% Fe). Moreover, 80% Zn + 20% Fe5.5 (5.5 kg ha−1 of 80% Zn + 20% Fe) was the best combination for increasing crude protein. Zinc applied alone enhanced Zn concentration in grain. In addition, Fe was slightly improved by an application of Zn and Fe in the first year, but a greater increase was observed in the second year, where 100% Fe13 (13 kg ha−1 of 100% Fe) was the best in improving Fe in grain. Foliar application of Zn and Fe is a practical approach to increase Zn and Fe concentration, and to improve the quality of wheat grains.

https://www.mdpi.com/2073-4395/9/5/250/pdf

Winter Wheat Grain Quality, Zinc and Iron Concentration Affected by a Combined Foliar Spray of Zinc and Iron Fertilizers

Interaction among plant nutrients can yield antagonistic or synergistic outcomes that influence nutrient use efficiency. To provide insight on this phenomenon, peer-reviewed articles were selected ...

https://www.tandfonline.com/doi/pdf/10.1080/00103624.2017.1407429

Chistian O. Dimkpa

Papers

Effects of Nutrient Antagonism and Synergism on Yield and Fertilizer Use Efficiency