Effect of Tillage and Crop Residue on Soil Chemical Properties and Rice Yields on an Acid Ultisol at Abakaliki Southeastern Nigeria

A study was conducted in 2008 and 2009 raining seasons, to evaluate the possibility of alleviating the degraded soil conditions at Abakaliki. The measures employed were combination(s) of different tillage methods [No-Tillage (NT), Hoe Tillage (HT), Ploughing (PL) and Ploughing and Harrowing (PH)] and crop residues [No Residue (NR), Rice Straw (RS), Burnt Rice Straw (BRS) and Legume Residue (LR)] treatments. Improved rice cultivars (ITA 257, Ex-China and ITA 315) were the test crops. The design of the experiment was a 4 x 4 x 3 factorial in a Randomized Complete Block Design replicated three times.. The results obtained showed that soil organic matter, pH, available P, exchangeable K, Ca, Mg and CEC significantly (p