Low soil available phosphorus (P) severely limits crop production in sub‑Saharan Africa. The present
study evaluated phosphate rock‑enriched composts as locally available low‑cost fertilizers for
sorghum production. The treatments consisted of sorghum straw, compost (COMP), phosphate rock
(BPR), BPR‑enriched compost (P‑COMP), BPR‑rhizosphere soil‑enriched compost (P‑COMP‑SOIL),
nitrogen‑phosphorus‑potassium treatment (NPK, 60–39–25), and control (NK, 60–25). Sorghum straw
and compost were applied at 1.34 tons ha −1 . N, P, and K in all treatments, excluding the control, were
adjusted to 60, 39, and 25 kg ha −1 , with urea, BPR, and KCl, respectively. Sorghum vr. kapelga was
cultivated and soil samples were collected at the S5, S8, and S9 growth stages. P‑COMP‑SOIL and
NPK yielded better sorghum yields than the other treatments. The rhizosphere soil of P‑COMP‑SOIL
had high abundance of soil bacteria and AMF, and genes involved in P solubilization, such as: acid
phosphatase (aphA), phosphonatase (phnX), glucose dehydrogenase (gcd), pyrroloquinoline quinone
(pqqE), phosphate‑specific transporter (pstS). The superior performance of the P‑COMP‑SOIL was
associated with its higher available P content and microbial abundance. Multivariate analysis also
revealed vital contributions of N, carbon, and exchangeable cations to sorghum growth. Soils could
be amended with phosphate rock‑rhizosphere soil‑enriched composts, as an alternative to chemical
fertilizers.

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