Long Term Effect of Tillage and Organo-Mineral Fertilizer Application on Phosphorus Dynamics on Ferric Lixisol in Burkina Faso

Abstract

A Pot experiment was conducted on 30 years long term soils under different soils management to evaluate the effect of organic amendments and soil tillage on phosphorus evolution in Ferric Lixisol. Two (2) levels of incubation with and without sorghum bicolor were used with six (6) treatments: (1) Tillage with animal traction + 10 t manure / ha / year + 100 kg NPK (14-23-14-6S-1B) / ha + 50 kg urea (46 % N); (2) Tillage with animal traction + 100 kg NPK (14-23-14-6S-1B) / ha + 50 kg urea (46 % N); (3) Minimum tillage+ 10 t manure / ha / year + 100 kg NPK (14-23-14-6S-1B)/ ha + 50 kg urea (46% N); (4) Minimum tillage + 100 kg NPK (14-23-14-6S-1B) / ha + 50 kg urea (46 % N); (5) 30-years-old fallow and (6) control plot (continuous sorghum without fertilizer) from soil fertility sustainability trial. Each treatment was pretreated with carbon plus nitrogen or without nitrogen before the experiment. The results showed that tillage increased P availability by 70 to 273 % compared to fallow in general and the use of organic matter improved only P-NaHCO₃ by 83 %. The effect of nutrient (carbon and nitrogen) addition varied according to different fraction of P. P-NaHCO₃ with sorghum incubation seems to be more responsive to nutrient addition. Therefore, minimum tillage with organic and mineral fertilizers amendments has beneficial effect on available P fractions.