ENHANCINGAGROECOLOGICALPERFORMANCEANDNUTRICTIONAL QUALITYOFPIGEONPEA(CAJANUSCAJAN) IN TROPICALSOILSTHROUGHTHE INTEGRATIONOFBIOCHARANDINDIGENOUSWEEDBIOMASS
Abstract
This research investigates how incorporating biochar with biomass from African nutmeg
(Monodoramyristica) and Cherry laurel (Prunus laurocerasus) can support Cajanus cajan
(pigeon pea) under tropical conditions. The study’s aim was to compare the effects of
individual versus combined applications of these amendments on plant vegetative growth, as
well as physiological indicators (chlorophyll concentration, proline levels, and nitrate
reductase activity) and nutritional compounds of interest to human consumption (carotenoids,
lycopene, and vitamin C). Nine experimental containers were prepared with biochar, each
receiving different biomass treatments, while three additional bags acted as controls.
Treatment layout included: first row: no amendment (control), later receiving 10 g each of
cherry laurel and kitchen waste at 46 days, second row: African nutmeg biomass only; third
row: Cherry laurel weed-biomass only; fourth row: a mixture of African nutmeg and Cherry
laurel biomass. Growth metrics such as plant height, stem girth, number of leaves, and
branching were recorded. Physiological assessments evaluated chlorophyll concentration,
proline content, and nitrate reductase activity. Nutritional measurements for carotenoids,
lycopene, and vitamin C were conducted at around 60 days after sowing.Results indicated that
the combined biomass treatment consistently produced the most robust vegetative
development, showing the greatest increases in height (~12 cm), leaf number (~259 leaves),
and branching (~32 branches) by 49 days . Physiologically, these plants displayed higher
chlorophyll content (suggesting improved photosynthesis), elevated proline (implying
enhanced stress resilience), and greater nitrate reductase activity (indicating superior nitrogen
assimilation).The nutritional profiling showed that the combination of African nutmeg and
Cherry laurel generated the highest concentrations of carotenoids, lycopene, and vitamin C in
leaves. Cherry laurel by itself was especially effective in increasing carotenoids and lycopene,
while African nutmeg alone provided modest improvements in vitamin C content.The control
consistently showed minimal growth, physiological, or nutritional enhancement.Overall,
these findings emphasize that using multiple organic amendments together with biochar plus
mixed amendments can amplify soil fertility, boost plant health, and improve the nutritional
composition of pigeon pea leaf tissue. The positive physiological responses (chlorophyll,
proline, nitrate reductase) promote plant vigor and resilience, while enriched phytochemicals
(carotenoids, lycopene, vitamin C) offer enhanced antioxidant and immune-support benefits.
This study advocates for the use of locally available organic biomass in sustainable
agricultural strategies designed to enhance food quality, soil health, and crop productivity in
tropical smallholder farming contexts
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