EFFECT OF MINERAL FERTILIZERS AND SOIL AMENDMENTS AND METHODS OF FERTILIZER APPLICATION ON REDUSING AMMONIA VOLATILIZATION AND GROWTH AND YIELD OF CABBAGE Brassica OleraceaVar.Capitata.L)

Abstract

A laboratory experiment was conducted in the laboratory of Soil Science and Water Resources Department, and field experiment in the field of the College of Agricultural Engineering Sciences - University of Baghdad. Site Jadiriya to study the effect of mineral fertilization and soil amendments and methods of fertilizer application on reducing ammonia volatilization. The laboratory experiment was carried out according to the completely randomized design (C.R.D) and the field experiment according to randomized completely block design (R.C.B.D) with three replicates. The laboratory experiment included adding ammonium molybdate with (phosphate fertilizer, potassium fertilizer, both, rock phosphate, agricultural sulfur, plant ash, adding at 5cm depth) using sandy loam soil. The field experiment included eight treatments including nitrogen fertilizer application methods to cabbage crop T0: control (no nitrogen fertilizer added), T1: addition with grooves or cracks of plant side at a distance of 5 cm, T2: addition fertilizer on the surface, T3: addition with irrigation water, T4 : 5 cm depth, T5: 8 cm depth, T6: 10 cm depth, T7: mixing with soil in one batch when starting fertilization, Urea was added in three batches, 15 days after planting, 30 days after planting and 45 days after planting. The results of the laboratory experiment showed an increase in volatilization of ammonia by increasing phosphate rock levels, while the amount of volatile ammonia decreased in the presence of phosphate fertilizer, potassium fertilizer and the two together, agricultural sulfur and plant ash and adding at 5 cm depth. The results of the statistical analysis of the field experiment showed that the treatment T1 gave the highest rate of total yield and weight of the cabbage head and external leaves at 74.3, 51.4 and 23.12 Mg ha-1, respectively, The same treatment gave the highest dry weight rate for the above mentioned indicators except for non-eaten leaves (9.43 and 5.63 Mg ha-1) while treatment T5 gave the highest dry weight rate for external leaves.