Effect of Adding Zeolite and Agricultural Sulfur on The Availability of Phosphorus From Rock Phosphate and Some Chemical Properties and Growth of Maize in Calcareous Soil

Abstract

A field experiment was carried out in one of the fields of the College of Agricultural Engineering Sciences, University of Baghdad - Al-Jadriya, research station (A) on maize plant, synthetic varieties type (Fajr 1), in the autumn season during the agricultural season 2021-2022 to study the effect of adding zeolite and agricultural sulfur on the availability of phosphorus from Rock Phosphate and the growth of maize in calcareous soil with a loam texture. Agricultural sulfur was used with two levels (0, 2) μg.ha-1, which was added two months before the sowing date, and natural zeolite, which was added at sowing with two levels (0, 10) μg.ha-1, and Rock Phosphate, which was added at sowing with two levels (0, 80) μg.ha-1. While mineral phosphorus, was added in the form of DAP fertilizer according to the fertilizer recommendation for maize plants at a rate of (80) μg.ha-1 according to [1] with one level as a comparison sample with three replicates according to a factorial experiment within the randomized complete block design (RCBD), so that the number of experimental units to became (27) experimental units. Soil and plant samples were taken from the field during the two stages of plant growth (before flowering and harvesting). The results showed a significant effect of the triple interaction of adding agricultural sulfur, zeolite, and Rock Phosphate on the soil phosphorus availability at the harvesting stage which amounted to 10.15 mg.kg-1. The treatment of adding mineral fertilizer alone was 5.07 mg.kg-1, compared with the control treatment which amounted to 2.01 mg.kg-1. However the concentration of absorbed phosphorus in the plant at the stage before flowering was 916.10 mg P.plant-1, and for the treatment of mineral fertilizer alone, 519.90 mg P.plant-1, and for the control treatment amounted to 104.60 mg P.plant-1, respectively. The results also indicated the role of the triple interaction in decreasing the degree of soil reaction (pH) and increasing the degree of electrical conductivity (EC). The degree of pH reaction for the triple interaction treatment was 7.50 and 7.60, for the mineral fertilizer treatment 8.10 and 7.77, and the control treatment 8.13 and 8.13, respectively. The electrical conductivity EC for the triple interaction treatment was 3.00 and 2.84 dS/m, for the mineral fertilizer treatment 2.45 and 2.79 dS/m, and for the control treatment, which amounted to 2.33 and 2.24 dS/m during the two stages of plant growth before flowering and harvesting, respectively. The mineral zeolite alone affected the increase of the cationic exchange capacity (CEC) of the study soil which amounted to 24.27 and 25.70 Cmol.kg-1 during the plant growth stages before flowering and harvesting, respectively.