Chemical properties and microbial responses to biochar and compost amendments in the soil under continuous watermelon cropping

Abstract

Biochar added to soil can improve crop growth and productivity. However, the mechanisms of crop growth improvement by biochar application are not well understood, particularly in the presence of soil-borne pathogens caused by continuous monocropping. Thus, a two-year field experiment was carried out to study the chemical and microbiological response of Lixisols (pH 5.8) to the amendment of biochar and its effect on watermelon productivity and Fusarium wilt disease incidence. Biochar was added alone or together with compost before watermelon transplanting. Mixed application of biochar with compost significantly increased watermelon yield as compared to adding compost or biochar alone. However, biochar had no effects on Fusarium wilt disease incidence in both years. Combined application of biochar with compost significantly increased contents of soil NH<sub>4</sub><sup>+</sup>-N, available phosphorus (P) and available potassium (K). Soil Biolog data indicated that the Shannon-Weaver diversity index and evenness index were increased significantly in the combined application of biochar with the compost treatment. There was a significant positive correlation between watermelon yield and soil NH<sub>4</sub><sup>+</sup>-N, available P, available K, microbial diversity or microbial evenness in the continuous watermelon monocropping system.

Effect of Biochar and Irrigation on Soybean-Rhizobium Symbiotic Performance and Soil Enzymatic Activity in Field Rhizosphere

“…Therefore, the hydrolytic activity of the FDA is considered as an indicator of total microbial activity. The FDA hydrolytic activity was shown to be increased by biochar addition in a pot experiment [15], whereas no effect was found in a field study [33]. Another extracellular enzyme, protease, catalyzes the hydrolysis of the protein components in the N mineralization process, especially in the initial stage [34].…”

Influence of Soil Amendments on the Growth and Yield of Rice in Acidic Soil

“…It is also one of the most important biochemical indicators for plants [28]. During this study, a rapid increase of chlorophyll was observed at the early growing stage (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29). The chlorophyll content of rice subjected to the compost treatment was significantly higher followed, by those plants applied with biochar and GML.…”

“…The chlorophyll content of rice subjected to the compost treatment was significantly higher followed, by those plants applied with biochar and GML. This significant increase may be due to the improvement of the nutritional condition of soil, which can reflect the growth of the plant and the chlorophyll content [6,29].…”

Effect of fertilization, carbon‐based material, and redmud amendments on the bacterial activity and diversity of a metal(loid) contaminated mining soil

“…This parameter reflects the activity of several enzymes, such as lipases, esterases, and proteases (Araujo et al, 2015) and is considered by Adam and Duncan (2001) to be directly proportional to the bacterial population. Since metal(loid)s have a negative impact on several enzymes (Yun, Yan, Dejie, Qiujun, & Guangfei, 2017), the increase in FDA hydrolysis activities with RM2 can indicate a reduced metal(loid) toxicity in this treatment, which coincides with an improvement of the physicochemical soil conditions (increase in pH and nutrient availability, and decrease in soil pore water Pb concentration and availability) (Table S1; Lebrun et al, 2020). However, other treatments also revealed an improvement of these physicochemical conditions, at similar levels as RM2 in some cases, but these were not coinciding with an improvement of the global microbial activity assessed by FDA hydrolysis.…”