Abstract: In order to improve the quality of cultivated land and reduce the application of chemical
fertilizer, a field experiment of humic acid application was carried out. Four treatments were set in the
experiment, T1 was conventional fertilization, T2 was conventional fertilization+600 kg/hm2
humic
acid, T3 was conventional fertilization+1 200 kg/hm2
humic acid, T4 was conventional fertilization+
1 800 kg/hm2
humic acid. The effects of humic acid on soil physicochemical properties, bioavailability
of heavy metals and onion yield of irrigation desert of Hexi Corridor were studied. The results showed
that after the application of humic acid, the soil pH value decreased by 0.27%-0.69% compared with
conventional fertilization, the bulk density of soil decreased by 3.5%-6.9%, the organic matter, alkali
hydrolyzable nitrogen, available phosphorus and available potassium and yield increased by 3.3%-
4.7%, 8.6%-23.7%, 7.6%-21.1%, 15.9%-36.5% and 3.5%-5.3%, respectively. The availability of heavy
metals in soil could differtntly reduced by applying different amounts of humic acid, the available lead, available zinc, available copper and available cadmium decreased by 17.7%-18.5%, 4.4%-13.7%,
39.5%-44.7% and 17.1%-35.8%, respectively. The corresponding rational fertilization program could be
formulated according to different soil characteristics and humic acid characteristics. |