Cyanobacterial Biofertilizer as a Supplemental Fertilizer for Peaches: Yield, Trunk Growth, Leaf Nutrients and Chlorosis

Nitrogen is the nutrient which has the greatest effect on peach (Prunus persica) productivity and quality. Carbon assimilation is dependent upon adequate levels of N in leaf tissue. Cyanobacteria can fix gaseous N from the atmosphere enzymatically, and this N fixation can be exploited in a cyanobacterial biofertilizer production system, which allows farmers to grow their own N source with relatively small energy inputs. Cyanobacterial biofertilizer (Anabaena spp.) was grown on an organic peach farm in Hotchkiss, Colorado, and applied to a peach orchard as a supplement to dried chicken manure. Peach fruit yield, trunk cross sectional area, leaf tissue nutrient concentrations, and soil plant analysis (SPAD) chlorophyll meter values (an estimate of leaf chlorophyll concentration) were measured. Chicken manure fertilization supplemented with cyanobacteria had higher yield than manure alone. Trunk cross sectional area increased less for treatments with cyanobacteria. Contrasting treatments which received cyanobacteria with those that did not marginally significant increases in S, P, and Cu leaf tissue concentration were seen, and decreases in Ca concentration. SPAD values were positively correlated with leaf Fe concentration, indicating that chlorosis may have been due to Fe deficiency. Overall, insufficient evidence was found to suggest cyanobacterial biofertilizer would be beneficial use of resources for peach growers.