Abstract
A field experiment was carried out to investigate crop productivity, emissions of carbon dioxide (CO2) and nitrous oxide (N2O), and soil quality of an upland field treated with compost and varying rates of biochar (BC) derived from soybean stalks during crop growing periods in a corn and Chinese cabbage rotation system. Compost was supplemented with BC derived from soybean stalks at varying rates of 5, 10, 15, and 20 t ha−1 (BC5, BC10, BC15, and BC20, respectively); the control (BC0) area was untreated. Our results reveal that crop productivity and emissions of CO2 and N2O varied significantly with the biochar application rate. Moreover, irrespective of the biochar application rate, crop productivity was improved after BC application as compared to the control treatment area, by 11.2–29.3% (average 17.0 ± 8.3%) for corn cultivation and 10.3–39.7% (average 27.8 ± 12.7%) for Chinese cabbage cultivation. Peak emissions of CO2 and N2O were mainly observed in the early period of crop cultivation, whereas low CO2 and N2O emissions were determined during the fallow period. Compared to the control area, significant differences were obtained for CO2 emissions produced by the different biochar application rates for both crops. During the two cropping periods, the overall N2O emission was significantly decreased with BC5, BC10, BC15, and BC20 applications as compared to the control, ranging from 11.1 to 13.6%, 8.7 to 15.4%, 23.1 to 26.0%, and 15.0 to 19.6%, respectively (average 16.9% decrease in the corn crop period and 16.3% in the Chinese cabbage crop period). Soil quality results after the final crop harvest show that bulk density, soil organic carbon (SOC), pH, and cation exchange capacity (CEC) were significantly improved by biochar application, as compared to the control. Taken together, our results indicate that compost application supplemented with biochar is potentially an appropriate strategy for achieving high crop productivity and improving soil quality in upland field conditions. In conclusion, appropriate application of biochar with compost has the concomitant advantages of enriching soil quality for long-term sustainable agriculture and reducing the use of inorganic fertilizers.
Highlights
Fertilizers are substances applied to the soil for nourishing plants and benefitting their growth
The higher biochar application rates contributed to changes in N2O emissions, with N2O emissions tending to gradually decrease
At high application rates (10–20 t ha−1), crop yields were increased for both corn and Chinese cabbage in the rotation system, after application of biochar to an upland field in South Korea
Summary
Fertilizers are substances applied to the soil for nourishing plants and benefitting their growth. Based on their convenience and efficacy, chemical fertilizers are important materials that contribute to increasing the crop yield and securing stable crop productivity [1]. Overuse of chemical fertilizers on agricultural land results in an imbalance of nutrients in the soil and lowers the soil organic matter content [2]. Chemical fertilizers are regularly applied to maintain the stability of crop production in South Korea, resulting in a considerable increase in usage, from 233 in 2010 to 268 kg ha−1 in 2016 [5]. The use of chemical fertilizers per hectare in South Korea is classified
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