Repercussions of fertilization with boron and enriched organic manure on soil chemical characteristics, boron and phosphorus fractions, and French bean productivity in an acidic Inceptisol of eastern Himalaya

Boron (B) and phosphorus (P) in the soil are dispersed in numerous geochemical fractions (forms) which depend primarily on physicochemical properties of soils, climate and management exercises, and each form is in dynamic equilibrium with each other. The study of these fractions caters for an advanced understanding of their bioavailability to plants. To better elucidate how the nexus of B and enriched farmyard manure (EFYM) synergy influences the soil chemical characteristics, B and P fractions, and French bean pod production, an investigation was undertaken during the three consecutive years from 2015 to 18 in acidic Inceptisol of eastern Himalaya. The experiment was laid out in symmetrical factorial design and the imposed treatments comprised four graded levels each of B (0, 0.5, 1 and 1.5 kg ha-1) and EFYM (0, 5, 10, 15 Mg ha-1). The results implied that the conjoint (interaction) application of a higher rate of B @ 1.5 kg ha-1 and EFYM @ 15 Mg ha-1 (B1.5EFYM15) levels were superior to other treatment combinations in improving soil chemical characteristics including pH, electrical conductivity (EC), soil organic carbon content (SOC) and reducing the concentration of iron oxides (Fe2O3) and aluminium oxides (Al2O3). Similarly, there was a significant increase of B fractions, total B, Hot water-soluble B (HWS-B), P fractions, total P and available P in the soil. Correspondingly, the maximum average French bean pod yield (FBPY) (12.04 Mg ha-1) was achieved under plots fertilized with B1.5EFYM15, while the minimum FBPY (7.82 Mg ha-1) was logged under B0EFYM0 (control). The correlation study exhibited a significant positive correlation amongst EC, SOC and cation exchange capacity (CEC) with both the B and P fractions. Of the various B fractions, readily soluble B (RSB) followed by organic bound B (OBB) was the most overriding B fraction affecting the available B. Likewise, concerning the P fraction, Resin P followed by bicarbonate extracted inorganic and organic P fractions (BiCPi and BiCPo), was realized to be the overriding P fraction implicated in affecting the available P. Higher phosphorus activation coefficient (PAC) was logged in those plots fertilized with B1.5EFYM15. The inclusive findings indicated that the addition of the successive increase in the level of B and EFYM up to B1.5EFYM15 can enhance the status of soil characteristics, diverse B fractions, total B, Hot water-soluble B (HWS-B), P fractions, Total P and available P and ultimately the FBPY in an acidic Inceptisol of eastern Himalaya.

Automated summary

The study of boron and phosphorus fractions in soil can help us better understand their bioavailability to plants. This study found that applying higher levels of boron and enriched farmyard manure can improve soil chemical characteristics, increase boron and phosphorus content, and ultimately enhance French bean pod production.