Assessing Soil Phosphorus Availability and Dry Matter Production of Choy Sum (Brassica chinensis var. parachinensis) on a Tropical Acid Soil By using Rice Husk Biochar

Phosphorus (P) is an important macronutrient for plant growth and development. However, phosphorus deficiency in tropical acid soils is a common problem because soluble inorganic phosphorus is fixed by iron. The application of biochar amendments could be used to mitigate phosphorus fixation in acid soil by reducing aluminium and iron availability in these soil. Thus, the objectives of this study were to (1) characterized the selected physico-chemical properties of soil samples, (ii) determine the soil
phosphorus availability (iii) assess the selected plant growth parameters of Brassica chinensis var. parachinensis (plant length, number of leaves, root length, dry weight
shoot and root) upon amending chemical fertiliser with commercial rice husk biochar. A pot trial was conducted for 30 days and chinensis was used as a test crop. The soil
samples were then collected and analysed at the end of pot trial. Rice husk biochar significantly increased soil pH compared with non-amended biochar. Additionally, rice
husk biochar also significantly declined exchangeable acidity and exchangeable of aluminium and iron. As a result, phosphorus availability increased within the soil due to
high affinity of biochar towards aluminium and iron drive efficient of inorganic P absorption which causing an increased in available P nutrients uptake. The results also
showed that increasing the availability of phosphorus in soil, improved the dry matter production of chinensis through declining the aluminium and iron concentration within the soil.