The effect of humic acid on biological properties of soil and upland rice plants in entisol Coastal Bengkulu City

Universitas Bengkulu, Departement of Soil Science, Faculty of Agriculture, Bengkulu, Indonesia

^* Corresponding author: yudhyhb@unib.ac.id

Abstract

Entisol is a type of soil on coastal land that has low soil fertility, low soil aggregation, low organic matter content, low soil microorganism activity and high salt content that can affect growth and development of crop yields. Application of humic acid is expected to increase the fertility of the entisol soil. This study aims to measure the effect of humic acid application on soil biological properties and yields of upland rice in Entisol Pesisir, Bengkulu city. The research was carried out in July-November 2020 in the Beringin Raya Village, Muara Bangkahulu District, Bengkulu City. The research design used a two-factor Completely Randomized Block Design with four replications, arranged in a factorial manner in experimental units. The first factor is humic acid which consists of not given humic acid, and given humic acid. The second factor is upland rice varieties consisting of Inpago 10, Merah rice, and Putih rice. The results showed that the application of humic acid was able to increase the biological activity of the soil including the total microbial population of 68.73% and the percentage of root colonization reaching 23.65% and increasing the pH, and rice yields per plot reached 14.2%. Inpago variety has better adaptability than local varieties (Merah and Putih) which is indicated by soil biological activity such as total microbial population reaching 570.16 x 10⁶ CFU g^-1 with root colonization percentage reaching 88.75%, pH, and upland rice yield per plot was 2033.68 g/plot. So based on the results of the study, it is recommended to cultivate Inpago 10 varieties compamerah to local varieties.