2016 International Conference on Clean Water, Air & Soil (CleanWAS 2016)

102 / 2016-07-27 09:19:26

Straw biochar improves the physical and chemical properties of the coastal mudflat soil

Nowadays, the coastal mudflat lands have generally been used for agriculture. However, coastal mudflats belong to the seashore saline soil family, and often contain electrical conductivity (EC, 20～40 ms cm-1) and high levels of exchangeable sodium percentage (ESP: 30～50%), that can adversely affect plant growth. These properties could be improved through removal of Na+ from the coastal mudflat lands.
Given that biochar has high concentrations of organic carbon, high porosity and surface area, improvement in soil physical properties including soil structure and water holding capacity would be expected following incorporation into soils. The current study examined the applicability of wheat straw biochar to improve the physic-chemical properties of coastal mudflat lands together with plant response.
Soil was incorporated with wheat straw biochar at 5 different rates; 0%, 5%, 10%, 15% and 20% (w/w) distributed to plastic boxes. The four rice seedings (Huayou 14) was selected to be transplanted into each equilibrated pot. All treatments were duplicated and the experiment lasted 110 days. During this period, the soil properties of pH, EC, ESP, cation exchange content (CEC), oxidation-reduction potential (Eh), water-soluble cations & onions, total organic carbon, total nitrogen were investigated; the rice height and tillering were observed, to assess the changes in soil properties with biochar treatment. The results showed that the biochar increased the soil organic carbon content, while decreasing the ESP. The highest dry weight rice yield was observed from soil which received 10～15% biochar. Moreover, increased potassium, source from the BC, induced mitigation of Na uptake by rice and consequently, reduced the impact of salt stress.