2014 ASHS Annual Conference

The goal of this greenhouse study was to investigate the drought tolerance effects of magnetized, chelated liquid iron fertilizer on two water stressed legumes. The objectives were to quantify the effects of four treatments on foliar gas exchange, soil moisture, and plant growth for velvet bean (Mucuns pruriens) and soybean (Gylcine max) plants.  The four treatments included two foliar applications for chelated liquid iron fertilizer (2.5 and 5%) with a conventional boom sprayer with and without magnets in the spray lines.    Plant and soil measurements were then recorded during two separate water stress events that lasted 24 and 13 days, respectively.  Stomatal conductance, transpiration, and internal carbon dioxide increased by 31, 46, and 24% for the magnetized fertilizer applications when compared to baseline data. In contrast, stomatal conductance did not change while transpiration, internal carbon dioxide, and leaf temperature increased for the non-magnetic treated plants.  During the second water stress event stomatal conductance was positively correlated with soil moisture (0.2311) for the non-magnetic application, but was negatively correlated (-0.0903) with the magnetic application. Photosynthesis increased by 15 and 21%, for soybeans and velvet beans, respectively, for the magnetized iron fertilizer (2.5%) application, when measured during the second water stress event. Also, photosynthesis was positively correlated with soil moisture (0.3233) and negatively correlated (-0.1220) for the non-magnetic and magnetic applications, respectively, during the second water stress event. Instantaneous water use efficiency increased 114% for the magnetized fertilizer when compared to the non-magnetized applications, for both water stress events when averaged across the fertilizer rates and legume species.  Improved drought tolerance in row crops such as dry beans and soybeans, with a single magnetized fertilizer application, would be cost effective, and easily adapted into current cropping systems.  Soybean irrigation rates would decrease approximately 108,617 to 203,652 gal/ac/yr if crop water use efficiency could be increased by 20 or 30% with a single, magnetized fertilizer application to the crop foliage.