A tillage-fertilizer combination that can improve physical soil quality is urgently needed to keep the resource base from further degradation. Long-term (5-year) study on moldboard ploughing and combined application of chemical fertilizer with (annual) farmyard manure (FYM) improved wheat-maize cropping system yield on a sandy loam soil. The combination of the treatments removed the compact layer, reduced soil bulk density, and increased the infiltration as compared to shallow tine cultivation. In shallow cultivation the AB horizon, which had the lowest infiltration, remained intact. Bulk density correlated better with changes in 60-300 μm sized pores than that of any other pore sizes determined by water retention. Originally, AB horizon had the lowest 60-300 μm radius pores, although, the 30-60 μm radius and smaller pores were greater or equal. To its effective depth, moldboard tillage increased 60-300 μm size pores, especially when the chemical fertilizers and FYM were applied in combination.
M. Saleem Akhtar , Abid Hussain , M. Azhar Naeem and Abdul Razzaq , 2001. Bulk Density, Infiltration, and Water-retention in a Sandy Loam Soil under
Long-term Tillage and Fertilizer Treatments. Pakistan Journal of Biological Sciences, 4: 542-549.