RESPONSES OF WOROWO [Senecio biafrae (Oliv. & Hiern.) S. Moore] TO COMPOSTS ENRICHED WITH ORGANIC NITROGEN SOURCES

Abstract

Worowo (Senecio biafrae) is a semi-wild, indigenous and nutritious vegetable. Demand for worowo is increasing due to its nutritional values, thus necessitating its domestication for increased production. However, there is limited information on soil fertility requirements of worowo and the use of inorganic fertilisers for its production could be expensive and detrimental to environment. Composts are more environmentfriendly and effective in improving soil fertility but their use are constrained by low nitrogen contents, thereby necessitating enrichment with various nitrogen sources. Therefore, responses of worowo to organically nitrogen-enriched composts were investigated. Composts from Cattle Dung+Sawdust-CDS at 1:1 (w/w) and Poultry Droppings+Sawdust-PDS at 1:1 (w/w) were enriched to 15, 30, 45 and 60 g N/kg with meals from dried bone-BnM, blood-BM, hoof-HM, and horn-HnM, neem-Nm and Tithonia leaves-TM. Compost treatments obtained were: CDS and PDS (no enrichment added), CDSBnM, CDSBM, CDSHM, CDSHnM, CDSNM and CDSTM; PDSBnM, PDSBM, PDSHM, PDSHnM, PDSNM and PDSTM. Compost treatments (30 t/ha) in 2.0 kg soils and control (soil alone) were incubated for 16 weeks for nitrogen analysis. Worowo was raised in pots with CDS, PDS and 60 g N/kg enriched composts at 30 t/ha and control (soil alone), compared with 60 kg N/ha NPK 15-15-15 in a completely randomised design with three replicates. Edible Shoot Yield (ESY) of worowo (t/ha) was measured at 180 Days After Planting (DAP). On the field, effects of CDSNM (60 g N/kg) at 0, 10, 20, 30 and 40 t/ha were compared with NPK 15-15-15 at 60 kg N/ha on the ESY of worowo at 180 DAP, using randomised complete block design with four replicates, in two raining seasons. Samples of worowo edible shoots at harvest at the two seasons were analysed for Crude Fibre-CF (%). Data were analysed using descriptive statistics and ANOVA at α0.05. Highest and least N (g N/kg) contents (9.2 and 0.4) from soils incubated with compost treatments were from CDSNM at 60 g N/kg (16 weeks) and control (8 weeks), respectively. In pots, ESY (t/ha) of 60 g N/kg CDSNM (54.93±1.91) was significantly higher than NPK (36.53±1.27) and others but similar to CDS (50.93±1.77) while pots treated with PDS were lowest (8.00±0.28). At first season on the field (180 DAP), CDSNM at 40 t/ha had the highest ESY (8.66±1.24) which significantly differed from other treatments except CDSNM at 30 (6.30±0.90) and 20 (5.53±0.79) t/ha while control gave lowest (3.00±0.43). The ESY (180 DAP) from CDSNM at 40 t/ha (10.55±1.95) was highest in the second season and differed significantly from other treatments but comparable to CDSNM at 30 t/ha (7.30±1.35). Lowest ESY (1.41±0.26) was from plots allotted to NPK. At first season, CF contents of 60 g N/kg CDSNM treatments, NPK 15-15-15 and control were in the order: 40 t/ha-12.00±0.59> NPK-11.20±0.59> 30 t/ha-11.00±0.59> 20 t/ha-10.62±0.59>Control- 10.50±0.59> 10 t/ha-10.45±0.59, which followed the same order at the second season. Cattle dung-sawdust compost enriched with neem to 60 g N/kg applied at 30 t/ha improved edible shoot yield and crude fibre of worowo, hence could be adopted for its production.