Effect of Timing and Level of Addition of Chemical and Organic Fertilizers on Nutrient Availability and Growth and Yield of Carrot (Daucus Carota)

Abstract

A field experiment was carried out in one of the agricultural fields of the Department of Plant Protection - Department of Organic Agriculture located in the governorate of Baghdad - Al-Qurayat region for the winter season 2019-2020 in soil with a mixed alluvial texture in order to study the effect of levels of organic and mineral fertilization and the date of their addition on the readiness of some nutrients in the soil and growth characteristics and the carrot yield (Daucus carota), in order to determine the best amount of fertilizer and the best addition time, a working experiment was carried out according to a randomized complete block design (RCBD). The study factors included two dates for addition, as the first date for addition was with planting, which is symbolized for (w) and the second date after planting four weeks after planting, which is symbolized for (a) and in three batches commensurate with the stages of plant growth. Fertilizer recommendation, (0) without addition and (50%) (100-40-100) and (100%) (200-60-200) kg hˉ¹ for each of the (NPK)which are denoted by (C0, C1 and C2) respectively Organic fertilizer (decomposed sheep waste) was added in two levels, which are without addition (0) and (15 ton hˉ¹), which is symbolized for (OM0 and OM1) respectively, and carrot seeds (Daucus carota) variety (Nantes-Castle) were planted in the form of lines inside the panels. On 10/31/2019 for the autumn season, with three replicates in the panels of 1 m² area, and the transactions were distributed randomly so that each duplicate contains 10 transactions, thus the number of experimental units for the experiment is 30 experimental units. The following results showed:Adding (100%) of the fertilizer recommendation to the mineral fertilizer at the second date (a) had a significant effect on increasing the concentration of nitrogen, phosphorus and potassium in the soil, as the treatment (C2aOM1) gave the highest concentration of nitrogen, phosphorus and potassium in the soil after the stage of uprooting plants (130 days after planting) concentration (36.96, 21.88 and 222.4) mg kg for each of N (P and K). The overlap treatment also outperformed 100% mineral fertilizer + organic fertilizer + second addition date (C2aOM1) by giving the highest total yield (81.67 ton hˉ¹) and giving the highest values of vegetative growth characteristics.