Can Hydroxyapatite and Boron Oxide Nano-fertilizers Substitute Calcium Superphosphate and Boric Acid for Broccoli (Brassica oleracea var. italica) Grown on A Heavy Clay Soil?

Nano-fertilizers are effective substitutes for the traditional ones. However, to what extent can nano hydroxyapatite (NHA) and nano-boron oxide (NBO) be suitable substitutes for calcium superphosphate(CSP) and boric acid (BA)? The answer required conducting a field experiment on broccoli (Brassica oleraceavar. italica) cultivated on a heavy claysoil for two successive seasons of 2016/2017 and 2017/2018.The nano form of NHA surpassed CSP by 14.2 to 17.8 % for leaf area and 13.6 to 15.8% for total head yield. Foliar spray with NBO increased leaf area, head yield and vitamin C content in heads as compared with BA. P and B contents in broccoli shoots receiving the nano forms surpassed those of the conventional fertilizers. Combined application of the two nano-fertilizers surpassed the combined application of the two conventional fertilizers by 16.0 %. Values for yield and yield components were significantly positively correlated with P and B contents in plant shoots and heads.