Partial Replacement of the Mineral Nitrogen Fertilizers by Organic Alternatives in Sandy Soils

Abstract

Aims: A field experiment had been carried out to study the effect of partial substitution of the mineral nitrogen (N) fertilization by using the compost on the peanut productivity in sandy soil. Study Design: Each experiment was carried out in a complete randomized block. Twelve treatments resulting from the factorial treatment structure of two factors: compost with 3 rates (0, 11.90 and 23.81 Mg ha-1) plowed 25 days before peanut lines planting and mineral N with 4 rates (0, 119.05, 178.57 and 238.1 kg N ha-1) after 21, 40 and 55 days of peanut planting applied in the form of ammonium nitrate (33% N). Place and Duration of Study: During the two successive summer seasons 2012 and 2013. Methodology: Seeds of peanut were sown and fertilization practices were performed as recommended. Soil and plant analysis had been carried out according to references. Data were calculated, analyzed and fertilizers use efficiency indices were calculated. Results: It was found that the combination between both sources of N fertilizers has increased the soil available nutrients; NPK, Zn, Mn, and Fe, the peanut seeds yield and weight of pods yield as the fertilization rates increase compared with the non-fertilized control samples. The seeds yield had increased by 178.04%, 257.26% and 373.14% while the oil content of seeds increased by 1.55%, 1.63%, 8.69% for the compost/0 – mineral treatment, mineral/0 – compost treatment and the compost/mineral treatment, respectively. The seeds content of NPK, protein and total carbohydrates for the mentioned treatments had also increased. Conclusion: The numerical values of the N use efficiency indices of the organic compost were greater than those for the mineral fertilizer indicating the greater fertilizing effect of the former than the later. But high rates of a mineral fertilizer in presence of an organic one may diminish many of the N use efficiency indices due to loss by leaching or consuming in the microbial activity of OM.