|dc.description.abstract||Virginia's Coastal Plain region contains the majority of the state's agricultural production despite having low nutrient soils. The soils in this region are predominantly coarse-textured acid soils with low cation exchange capacities (CEC) (< 3 cmol kg-1) and thus frequently exhibit nutrient deficiencies, including cationic nutrients which are not easily lost by leaching in soils with greater CEC. As a result, soils require careful nutrient management to maintain production levels. Soybean (Glycine max), the world's fourth largest crop, shows sensitivity to manganese availability and regularly experiences deficiency symptoms in low-CEC coastal plain soils. Tomato (Solanum lycopersicum) production, one of the 3 largest vegetable production systems in the world, requires careful management of various nutrients, particularly phosphorous, sulfur, and boron, for proper fruit development.
Two novel coated fertilizer products consisting of granular KCl coated in a nutrient powder and a sugar-acid chelating agent are investigated as multi-nutrient sources for soybeans and tomatoes. A comprehensive review of the chemistry, behavior, and functionality of key nutrients provided by the fertilizer (P, S, Mn, and B) in both soils and plant tissues and the current state of chelate use in agriculture is provided along with related production issues with tomatoes and soybean.
A greenhouse study investigating the ability of the first coated product (Mn + B coated KCl) to provide micronutrients to soybeans was conducted. Using both low and high organic matter (OM) soils (10 g kg-1; 36 g kg-1), Mn + B coated KCl increased soil Mn compared to no fertilizer and uncoated KCl. Additionally, Mn + B coated KCl increased total above ground tissue Mn compared to control and uncoated KCl for the low OM soil but not for the high OM soil, which was likely due to OM leading to the formation of metal-ligand complexes. There were no significant results regarding B concentration in either the soil or plant tissue due to the low application rate provided by the coating.
The same fertilizer (Mn + B coated KCl) was investigated under field conditions to determine if increased soil and tissue Mn can be maintained under various environmental factors. Our results found that for all growing seasons and locations, there were no significant treatment differences between months for both Mn and B, but total monthly averages did fluctuate between months, probably reflecting changes in soil moisture and redox status. When averaged across the entire growing season, differences between treatments were inconsistent. Under field conditions, environmental conditions such as soil moisture and leaching likely masked any consistent treatment effects of the coated products.
Two potential soil amendments, P + S + B coated KCl and glucoheptonate (GH), were investigated for their ability to provide nutrients to tomatoes. Three greenhouse trials, each lasting 3 weeks, were conducted. In the first trial, P + S + B coated KCl was compared to the current agronomic recommendation rates for P, S, and B. The coated KCl significantly increased soil and plant tissue P and B compared to all but the KCl + P and KCl + B treatments. The second trial was a glucoheptonate rate trial and showed a significant positive correlation between GH rate and soil and tissue B. The third trial combined and compared the coated KCl and GH products and showed that the treatments containing the coated KCl had significantly increased P, S, and B soil and tissue concentrations, with GH application having no synergistic effect||en_US