Impact of Humic Acid and Some Nanomaterials on Alternaria Leaf Spot Disease and Sugar Beet Productivity

Abstract

The effect of humic acid (HA) and three Nano materials (NPs) on alternaria leaf spot (ALS) disease caused by Alternaria tenuis (Nees) and sugar beet (Beta vulgaris var. saccharifera L.) productivity were evaluated. Field experiments were conducted over two seasons in the Experimental Farm of Sakha Agricultural Research Station (SARS) (latitude of 31º֯10′ N and longitude 30º 93′ E, at an elevation of
14 m above sea level), Kafr El-Sheikh governorate. Three HA rates along with 100g/L of Boron (B), Manganese (Mn) and Iron (Fe) NPs were used. Generally, the obtained results showed that, all studied traits recorded variability in reaction and the final impact was depending on the significance of material combinations (HA rates x NPs). ALS severity was generally reduced due to the tested materials and it was significantly decreased using B NPs with 3kg HA/fed (2.93%) compared with the control (19.07%). Therefore, the same treatment also showed the highest content of T-phenol (254.13 meq/100 g FW) and the lowest value of alpha amino nitrogen (1.82 %). Moreover, sugar beet plants treated with B NPs alone had the highest values of proline (5.16 mg/g-1 FW), catalase enzyme (6.38 mM H2O2 g-1 FW min- 1), sucrose (15.68%), extractable sugar (13.09%) and sugar quality (83.50%) as well as the lowest value
(1.97%) of sugar lose to molasses% and Na+ content (1.41%). Furthermore, treatment of B NPs followed by the highest rate of HA (5kg /fed.) each one alone were recorded highest contents of Chlorophyll A (5.75 mg/g-1 FW), Chlorophyll B (2.99 mg/g-1 FW) and carotenoid (2.47 mg/g-1 FW). Additionally, Fe NPs alone or combined with 3kg HA/fed. resulted in the lowest value of K+ (5.63%) and the highest contents of peroxidase (0.607 mM H2O2 g-1 FW min-1) respectively. Meanwhile, the highest values of root yield (30.41 ton/fed.) and sugar yield (4.41ton/fed.) were obtained using Mn NPs and 5kg of HA /fed separately.