Responses of root physiological characteristics and yield of sweet potato to humic acid urea fertilizer

Abstract

Humic acid (HA), not only promote the growth of crop roots, they can be combined with nitrogen (N) to increase fertilizer use efficiency and yield. However, the effects of HA urea fertilizer (HA-N) on root growth and yield of sweet potato has not been widely investigated. Xushu 28 was used as the experimental crop to investigate the effects of HA-N on root morphology, active oxygen metabolism and yield under field conditions. Results showed that nitrogen application alone was not beneficial for root growth and storage root formation during the early growth stage. HA-N significantly increased the dry weight of the root system, promoted differentiation from adventitious root to storage root, and increased the overall root activity, total root length, root diameter, root surface area, as well as root volume. HA-N thus increased the activity of superoxide dismutase (SOD), peroxidase (POD), and Catalase (CAT) as well as increasing the soluble protein content of roots and decreasing the malondialdehyde (MDA) content. HA-N significantly increased both the number of storage roots per plant increased by 14.01%, and the average fresh weight per storage root increased by 13.7%, while the yield was also obviously increased by 29.56%. In this study, HA-N increased yield through a synergistic increase of biological yield and harvest index.

Nitrogen Fixing and Phosphate Mineralizing Bacterial Communities in Sweet Potato Rhizosphere Show a Genotype-Dependent Distribution

“…Changes were observed not only in the structure of this community but also in the abundance of alp genes after six months of growth. These changes could be explained by the fact that, at the late growth stage of sweet potato, the roots usually presented stronger nutrient absorption ability due to the increase of the number of root tips, the enlargement of root surface area, and the root volume [43]. Phosphate mineralizers may have contributed to the conversion of insoluble phosphates into available forms for plant via different processes such as acidification, exchange reactions, chelation, and production of gluconic acid [21,44].…”

Humic Acid Fertilizer Improved Soil Properties and Soil Microbial Diversity of Continuous Cropping Peanut: A Three-Year Experiment

“…Humic acid is a kind of organic matter produced and accumulated by animal and plant remains through the decomposition and transformation of microorganisms with a series of geochemistry processes. Combined with various inorganic fertilizers, humic acid can improve the soil quality, enhance fertilizer utilization rate 7,8 , and promote crop yield and quality 9–11 . Most of the current research focuses on the physicochemical state of humic acid to improve the soil quality while few studies have been conducted to investigate the influence of humic acid on soil microbes.…”

Response of Lentil to Crude Humates and Rhizobacteria Inoculation under Calcareous Soils Conditions

“…Although the stimulation effects of humate on growth parameters of plant are not fully clear, there are some theories which potentially work together including the beneficial physical, biological and chemical actions on soils and could increase plant growth (Chen & Aviad, 1990;Tufail et al, 2014). The positive effect of PGPR or humate, which stimulate the microbial activity in the rhizosphere (Table 4), on root surface area due to PGPR can produce a wide range of phytohormones (Vacheron et al, 2013;Chen et al, 2017).…”