Direct and residual fertilizer values of maize (Zea maysL.) stover co-compostedwith Tithonia diversifolia(Hemsl.) A. Graygreen manure

Abstract

The present investigation highlights and compares the direct and residual fertilizer values of maize (Zea mays L.) stover composted with Calliandra calothyrsus Meisn and Tithonia diversifolia (Hemsl.) A. Gray-green manure on maize (Zea mays L.) and successive potato (Solanum tuberosum L.). Two field studies were installed with maize and successive potato crops in a completely randomized block design (CRBD) with three replicates. Statistical analyses were performed using R commander, version 4.0.2. Grain yields, root biomass, above ground biomass and calculated parameters (Root/Shoot ratio, Harvest Index and GinningRate) were evaluated for maize. Total potato yields were evaluated and categorized into small size tubers (SST 65 mm). Treatments under evaluation were: T1=Control, T2=Farm (cow) manure alone, T3=Maize stover co-composted with Calliandra calothyrsus Meisn green manure; T4= Maize stover co-composted with Tithonia diversifolia (Hemsl.) A. Gray green manure; T5= Farm (cow) manure+45-60-30; T6= Maize stover co-composted with Calliandra calothyrsus Meisn green manure+45-60-30; T7=Maize stover co-composted with Tithonia diversifolia (Hemsl.) A. Gray green manure+45-60-30; and T8=Farm (cow) manure+FOMI Imbura+FOMI Totahaza. Obtained results indicated highest maize yields with FOMI organo-mineral fertilizers (2.7 T/ha) seconded by the recommended fertilizer practice T5 (2 T/ha). In the same line, highest R/S value (=0.38) was registered with the same FOMI treatment (T8), while the highest HI value (0.21) was observed with the maize stover co-composted with Tithonia diversifolia (Hemsl.) A. Gray (T4). Highest potato total yields were observed with the maize stover compost enriched with Tithonia diversifolia (Hemsl.) A. Gray and supplemented with mineral fertilizer (7.61 T/ha), followed by the same compost without mineral fertilizer addition (6.35 T/ha). We conclude our study with the following statements: i) the highest direct fertilizer value was observed with the FOMI treatment; ii) the residual fertilizer effects were more expressed with the maize stover co-composted with Tithonia diversifolia A. Gray green manure with or without mineral additive, followed by farm manure and maize stover enriched with Calliandra calothyrsus Meisn green manure. Consequently, we restate that the effects of compost-based organo-mineral fertilizers on crop yields should be definitely evaluated on a multiseasonal basis so as to fully capture their residual fertilizer potentials.