Assessment of Tillage/zero Tillage Farming Systems in Ultisols of Benin City, Nigeria

The study assessed both tillage/zero tillage farming systems in ultisols where pineapples (Ananas comosus (L)., Merr) were planted in the teaching and research farm, benson idahosa university Benin city, Nigeria. The aims were to compare both tillage/zero tillage systems. There after confirm which of the system would retain nutrients that can sustain pineapple growth. Therefore advice farmers on the method to adopt. First, soil samples collected were analysed. Then pineapple suckers were planted in both tilled and untilled soil. During the second and fourth years of pineapple growth, the soil was analysed again. The nutrients NPK were used as fertility indices. Pre-planted soils NPK content were 2.80g kg-1, 18.50 mg kg-1, 0.31 cmol kg-1 respectively. Compared to critical levels, N = 1.50 - 2.00 g kg-1[14] P = 10.00 - 16.00 mg kg-1 (adeoye and agboola, 1985), k = 0.20 cmol kg-1[5] the soil had a good nutrient status. During the second year of pineapple growth NPK values from tilled soil were, 1.40g kg-1, 9.30 mg kg-1 , 0.14 cmol kg-1, where as those from untilled soil were, 1.90g kg-1, 12.20mg kg-1, o.30 cmol kg-1 respectively. For the fourth year NPK values were, 1.05g kg-1, 8.50mg kg-1 0.10 cmol kg-1 from tilled soil and 2.40g kg-1, 19.40 mg kg-1, 0.28 cmol kg-1 from untilled soil. The study showed a significant (p = 0.05) decrease in the NKP comtent from the tilled soil during both the second and fourth year of pineapple growth. The reverse was the case in untilled soil where a significant (p = 0.05) increase in NPK was obtained, these findings confirmed that zero tillage encouraged nutrient retention in the ultisol, therefore its advisable for farming systems when growing pineapples.