Application of biochar and inorganic phosphorus fertilizer influenced rhizosphere soil characteristics, nodule formation and phytoconstituents of cowpea grown on tropical soil

Abstract

The effect of biochar alone or co-applied with triple superphosphate on rhizosphere soil characteristics, nodule formation, phytoconstituents and antioxidant property of cowpea ( Vigna uguiculata ) is yet to be adequately examined in sub Saharan Africa. A field experiment was conducted where cowpea ( Vigna unguiculata ) was grown in a tropical sandy loam soil amended with biochar at 1.5 t ha −1 and 2.5 t ha −1 solely or together with inorganic phosphate fertilizer (Triple superphosphate), applied at a rate of 60 kg P ha −1 . At 50% flowering, changes in selected rhizosphere soil properties (pH, total nitrogen, available phosphorus, soil organic carbon, cation exchange capacity), nodule count, phytochemicals (phenols, flavonoids, alkaloids, tannins, saponins) and antioxidant property of cowpea roots and leaves were determined by standard laboratory procedures. Differences between means of the measured parameters were established using ANOVA, and relationships among the parameters were explored using Pearson correlation (p < 0.05). Addition of biochar solely or in combination with TSP significantly (p < 0.05) increased soil pH, total nitrogen, available phosphorus, soil organic carbon, cation exchange capacity and root nodule count. Flavonoids, phenols, alkaloids, saponin, tannin contents and antioxidant activity in the roots and leaves were significantly (p < 0.05) higher in the amended soils compared with the unamended soil. Similarly, soil flavonoids, phenols, alkaloids and antioxidant activity were significantly higher in amended soils compared with control. Significant, positive inter and intra correlation with varying strength was found between soil properties, nodule number and phytoconstituents. This is an indication that biochar can be co-applied with triple superphosphate to sustain soil fertility, improve nodulation and enhance concentrations of phytoconstituents in soil, cowpea roots and leaves.

Fertilizer source and chitosan effect on productivity, nutrient accumulation, and phenolic compounds of Thymus daenensis Celak

“…The current study results agree with the recent reports by Phares et al. (2020) and Ostadi et al. (2020).…”

“…The current study results agree with the recent reports by Phares et al (2020) and Ostadi et al (2020). Phenolic acids such as cinnamic, carnosic, and rosmarinic acids contribute to thyme extracts antioxidant capacity (Jabri Karoui et al, 2016;Roby et al, 2013;Zengin et al, 2020).…”

Biochar amendment reduced the risk associated with metal uptake and improved metabolite content in medicinal herbs

“…The increase in pharmacologically active compounds in biochar treatments compared to control is consistent with the earlier studies that reported enhanced phenolic and flavonoid production in plants after biochar amendment in soil (Phares et al, 2020; Quartacci et al, 2017). The decrease in essential nutrient metal and photosynthetic parameters (CO 2 exchange rate, transpiration rate, and stomatal conductance) be the reason for the increased pharmacologically active compounds in plants treated with biochar (Jain et al, 2017; Saha et al, 2019; Yadav et al, 2018).…”

One-time application of biochar influenced crop yield across three cropping cycles on tropical sandy loam soil in Ghana

“…Regardless of the enormous benefit derived from biochar, its sole addition to soil to enhance fertility and crop yield has limitations; particularly plant based biochar. Often, plant based biochar is deficient in nitrogen ( Phares et al., 2020 ) as well as phosphorus ( Zhang et al., 2016 ). It must therefore be co-applied with compost, manure or inorganic fertilizer ( Adekiya et al., 2019 ; Phares et al., 2017 ).…”