TITLE:
Can Drainage, Dolomite, and Natural Phosphate Application Control Iron and Sulfide Content in Iron-Toxic Irrigated Rice Fields?
AUTHORS:
Cécile Harmonie Otoidobiga, Louis P. Yameogo, Pauline W. Ouedraogo, Kevin Stanislas Bationo, Massiribi Bintou Barro, Ganda Samiratou Zongo, Susumu Assakawa, Dayeri Dianou, Issa Wonni, Ynoussa Maïga, Aboubakar S. Ouattara
KEYWORDS:
Toxicity, Season, Fertilization, Drainage, Rice Variety
JOURNAL NAME:
Agricultural Sciences,
Vol.16 No.9,
September
18,
2025
ABSTRACT: Soil iron (Fe II) and sulfide toxicities are major constraints to irrigated rice productivity in Burkina Faso, West Africa. This study aimed to mitigate these challenges by trialing drainage, fertilization, and iron-tolerant rice varieties, considering seasonal variations. Field experiments were conducted in the dry and rainy seasons using two rice varieties: FKR76 (iron-sensitive) and FKR62N (iron-tolerant). Two drainage modes (D0: no drainage, D2: drainage every 14 days) and eight fertilization treatments were tested: unfertilized (F1), NPK + urea (F2), NPK + Urea + Dolomite + Zn (F3), and NPK + Urea + Natural Phosphate (F4), and each fertilization regime combined with organic manure (FO) and without organic manure (SFO). Soil samples were collected before rice plant transplanting to evaluate the number and activities of Iron-Reducing Bacteria (IRB) and Sulfate-Reducing Bacteria (SRB). At 60 days after transplanting (DAT), the soil Fe II and sulfide concentrations were measured. The results showed that both IRB and SRB activities were higher during the rainy season (p = 0.000), panicle development (p = 0.000), and grain yield (p = 0.0001) of the iron-sensitive rice variety (FRK76). These results indicate that dolomite and natural phosphate can effectively reduce iron and sulfide toxicity in rice fields across seasons, offering a promising strategy for sustainable rice production under challenging soil conditions.