Tillage effects on soil. Physical properties and sunflower (Heliantbus annuus) growth and yield in Ilorin, Nigeria.
Soil physical properties and sunflower (Helianthus annuus) yield under convectional tillage (CT) and zero-tillage (Z,TJ. was monitored for 3 consecutive years in Ilorin, Southern Guinea Savannah zone of Nigeria (SGSZN). While bulk density of CT increased slightly over the years, significant decrease of 12 and 8% were observed in ZT at 0.1 and O.2m depths respectively. Also, soil moisture release at 50 kPa increased from 7.5 to l4m3m-3 for ZT and 10 to 12.5m3m-3 for CT. Infiltration rate increased by 13% over the 3 years in ZT and decreased by 12% in C,T. Sunflower plant height and stem diameter were unaffected by tillage (P = 0.05) significantly higher head diameter and seed yield were observed in CT for 1990 and 1991 (P = 0.05) while in 1992 no significant difference was observed in head diameter and seed yield among the tillage treatments (P = 0.05). It was concluded that sunflower growth under ZT may be beneficial to the fragile soils of the SGSZN.
Keywords: Tillage, sunflower, yield, Soil moisture release, Infiltration rates.