Improving Soil Fertility and Maize Growth in Suboptimal Land Through Application of Humic Acid

Abstract

Humic acid (HA) has been reported to increase plant growth and crop yields, as well as improve soil fertility. However, the potential utilization of HA extracted from various organic waste composts as organic amendment in suboptimal soils has not been studied in depth. The experiment used a two-factor Completely Randomized Design (CRD) with three replications. Four types of HA were used, namely bagasse HA (BHA), water hyacinth HA (WHA), market waste HA (MHA), and commercial HA (CHA). It also comprised of four doses HA i.e., 0.05, 0.10, 0.15 and 0.20% (of soil on w/w base). The results revealed that fluctuations in soil pH and nutrient release with the HA application had a variable quadratic response pattern. Organic carbon increased by 17%, while total N and available P decreased by 5% and 38.6% during the last weeks of incubation. The HA application could improve the growth response and nutrient uptake of maize significantly. CHA0.20% was the best interaction treatment which had the highest average value on dry weight and NPK uptake, which were 98.0 g pot-1, 178.8 mg plant-1, 27.4 mg plant-1 and 216.9 mg plant-1, respectively. The scanning electron microscopic (SEM) showed that HA could increase in the length and density of maize root hairs. Furthermore, the HA application significantly increased pH, CEC, C-organic content and availability of soil nutrients.

Effect of Different Fertilization Measures on Soil Salinity and Nutrients in Salt-Affected Soils

“…Total soil nitrogen is another significant nutritional indicator. It has been demonstrated that humic acid increases total soil nitrogen [42], which is in agreement with our findings. Attapulgite clay treatment enhanced total soil N, and its application with organic material boosted total soil N considerably.…”

“…Humic acid lowered soil pH while increasing soil salinity [41][42][43], and the soil EC of organic fertilizer with humic acid slightly increased. Meanwhile, the pH of the treatment declined in the present study; a similar effect was observed in the previous study.…”

Evaluation of Cyperus Fertility Improvement in Aeolian Soils from an Application of Humic Acid Combined with Compound Fertilizer

“…Humic acid is a kind of high-molecular-weight organic matter in nature that mainly comes from the sediment of soil, water, and plants after microbial decomposition [9,10]. Studies have shown that humic acid has good chemical properties, and the addition of humic acid to soil can regulate nitrogen transformation in the soil and reduce nitrogen migration and loss in the soil [11,12]; improve the range of phosphorus in the soil; increase the content of available nutrients and organic matter in sandy soil [13]; improve soil structure and fertility [14,15]; improve the effectiveness of trace elements in the soil [16]; and promote crop growth [17].…”