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COMPARATIVE USE OF ORGANIC SUBSTRATES AND MINERAL FERTILIZERS IN GROWING MAIZE (ZEA MAYS L.) FOR MAINTAINING SOIL FERTILITY IN RAINFED AREA OF PAKISTAN

SHER MUHAMMAD^1* AND T.S. MUHAMMAD²

Abstract: At present Pakistan has 22 m ha of arable land out of which 4.59 million hectares are rainfed. About 1.8 million hectares of Pothowar Plateau comprises of Fatehjang¸ Murree¸ Attock and Jehlum. The topography of this region is uneven and sloppy lands are confronted with loss of fertility due to erosion problem. The rainfed area contributes about 24% in total crop yield of Pakistan. The fertility status of these soils ranges from low to very low. So, it is very important to adopt management strategies for nutrients replenishment in this area. Effects of mineral fertilizers, leguminous straw (chickpea) and leaf litter incorporated in an alkaline soil from Pakistan (0.80% C_org, 3.94 µg g^-1 soil,  NaHCO₃ extractable P 2.32 µg g^-1 NO₃-N, pH 8.2, EC_e 0.56 dS cm^-1, 18% clay, 6% CaCO₃) under growing maize condition were studied in a 100-day pot experiment. Mineral fertilizer, plant residues (leguminous straw and non-leguminous) and leaf litter were added in five different treatments including a non amended control to the soils prior to cultivation of maize. The treatments were (1) untreated control, (2) 100 kg/ha N (Urea) and 120 kg/ha P₂O₅ (diammonium phosphate), (3) 1% chickpea residue, (4) 1% maize straw, (5) 1% leaf litter. The shoot and root dry matter in treatment 3 and 4 was three to two times higher than in the control. Similarly, addition of mineral fertilizers and chickpea residue increased root biomass significantly. Total C and N contents in maize shoot and root were double in treatment 2 and 3 followed by treatments 4 and 5 as compared to control. Microbial biomass (C_mic, N_mic, P_mic) contents increased significantly after addition of leguminous straw (chickpea residue) and mineral fertilizers followed by maize straw and leaf litter. Maximum increase of C_mic was observed in treatment where leguminous straw was added followed by maize straw and leaf litter.
 

¹Department of Soil and Environmental Sciences,

University College of Agriculture, University of Sargodha, Sargodha, Pakistan²Department of Chemistry, Islamabad Model College for Girls, F-6/2, Islamabad, Pakistan