Effects of irrigation regime, organic and inorganic mineral source on growth and yield components of switchgrass (Panicum virgatum L.) in upland and lowland conditions in Sokoto, Nigeria.

The effects of organic, inorganic fertilizer and irrigation regime on yield parameters of P. virgatum in upland and lowland areas in Sokoto geoecological region of Nigeria were assessed. Four levels of nitrogen (0, 25, 50 and 75 kg N ha(-1)), three rates of farmyard manure (0, 5 and 10 t ha(-1)) and three irrigation regimes (w2, w4 and w6) were set up as a split -plots design. Farmyard manure and irrigation regimes were combined and allocated as the main plots, while nitrogen rates were assigned to the sub-plots and each replicated three times. Results revealed that raising nitrogen rate from 50 to 75 kg N ha(-1), farmyard manure rate from 5-10 t ha(-1) or irrigation intervals from 2 to 4 days did not show a significant (p > 0.05) increase in yield components evaluated. Dry matter accumulation was significantly (p < 0.05) affected by irrigation regime in both seasons and locations and 2 day interval irrigation had the highest dry matter yield. A significant interaction between nitrogen and manure application was observed only at upland in 2008/2009 and a combination of 75 kg N ha(-1) and 10 t ha(-1) manure produced the highest values in all the parameters evaluated. The study suggest that 50 kg N ha(-1) with 5 t ha(-1) of farmyard manure and 2 day irrigation interval gave the highest yield. A combination of 50 kg N ha(-1), with 5 t ha(-1) of farmyard manure and 2 day irrigation interval were found to be optimum for growth and yield of Switchgrass under both lowland and upland conditions in Sokoto geoecological zone of Nigeria.