Efficiency of Nanoparticle, Sulfate, and Zinc-Chelate Use on Biomass, Yield, and Nitrogen Assimilation in Green Beans

The introduction of nanofertilizers (Nfs) in agriculture has allowed the development of new technologies that enhance the productivity of crops. Within the most studied Nfs we find metal oxides, especially ZnO; however, the results of various experiments provide contradictory data on the growth variables. Therefore, this study intended to evaluate the efficiency associated with the use of nanoparticles, sulfates, and zinc-chelates in Phaseolus vulgaris L. cv. Strike grown in acid soil, as well as to evaluate its production, total biomass, and nitrogen assimilation. Phaseolus vulgaris L. cv. Strike plants were sprouted and grown in polyethylene bags containing 3 kg of acid soil (pH 6.8) in an experimental greenhouse and were watered with a nutritious solution. A completely randomized design including ten treatments and five repetitions was used. Treatments consisted of applying different zinc sources (sulfate, DTPA chelate, and zinc oxide nanoparticles) to four different doses (0, 25, 50, and 100 ppm of zinc). Results obtained indicated that the doses best favoring an increase in biomass, production, and nitrogen assimilation were 50 ppm of ZnSO4, 100 ppm of DTPA-Zn, and 25 ppm of zinc oxide nanofertilizers (NfsOZn). Hence, the dose containing 25 ppm of NfsOZn was the most efficient dose, since at a lower dose it was able to equalize biomass accumulation, production, and nitrogen assimilation as compared to ZnSO4 and DTPA-Zn sources. However, further research is required, given that high-concentration doses were toxic for beans. Finally, it is worth highlighting that zinc oxide nanoparticles have a huge potential to be used as nanofertilizers if applied in optimal concentrations.