Synergistic Effects of Coconut Husk Biochar and Palm Fiber on Soil Nitrogen and Phosphorus Dynamics and Pak Choi (Brassica rapa,subsp. chinensis) Nutrient Uptake
DOI:
https://doi.org/10.65422/loujas.v2i1.306Keywords:
Biochar, palm fiber, nitrogen, phosphorus, sandy loam, Pak Choi, deficit irrigation, soil amendmentAbstract
Sandy loam soil is considered to have a low capacity for water retention, making it highly susceptible to nutrient losses—particularly nitrogen and phosphorus-through leaching. This significantly reduces crop productivity under water-stressed conditions. The availability of nitrogen (N) and phosphorus (P) in such soils is influenced by several factors, including microbial activity and the decomposition of organic matter, which further complicates soil fertility management under limited irrigation systems.
A randomized field study was conducted using four soil treatments under low irrigation (water stress) conditions, with three replications, over a period of 35 weeks. The treatments included: untreated soil (T0) as a control, soil amended with coconut husk biochar (T1), soil amended with palm fibers (T2), and a 50:50 mixture of T1 and T2 at 5% each (T3). Throughout the study, nitrogen and phosphorus levels were measured weekly in both soil and plant tissues to evaluate soil fertility and crop productivity responses.
The results showed that treatment T3 achieved the highest concentrations of nitrogen and phosphorus in the soil, reaching 16 mg/kg for nitrogen and 22.6 mg/kg for phosphorus after the first week, compared to the control treatment (T0). It also produced the highest crop yield at harvest (110 kg), in addition to the highest nutrient content in plant tissues (4.6% nitrogen and 0.65% phosphorus). In contrast, treatment T2 (palm fibers only, as described) showed the weakest performance across all measured indicators, likely due to limited nitrogen mobility within the decomposing organic material.
Overall, the findings indicate that combining coconut husk and palm fibers is an effective strategy for improving nutrient retention in sandy loam soils, thereby enhancing agricultural productivity under conditions of limited irrigation and water stress.
