The effect of soil lime content and the form of nitrogen nutrition on the calcareous Chlorosis of some maize cultivars

The research was carried out in three fields of the Agricultural Scientific Research Center in Lattakia for two seasons 2020 + 2021, to study the effect of soil content of calcium carbonate in the three fields (A = 20%), (B = 48%) and (C = 68%), and three types of nitrogenous fertilizers (Urea CO (NH2)2 - Ammonium sulfate (NH4)2SO4 - Potassium nitrate KNO3), in addition to the control treatment without adding nitrogen, on the resistance of three varieties of yellow corn, Dina F1 (foreign variety), Fayhaa and Salmonia (local varieties) for calcareous chlorosis. The experiment was designed according to the split plot design and included 36 treatments with three replications for each treatment, so that the number of training plots was 108 experimental plots. The results showed that the treatment of Ammonium sulfate fertilizer increased the availability and absorption of some nutrients for the corn plant through its effect on the pH and some fertile soil properties, which reflected positively on the growth and productivity of the cultivated corn varieties. At high levels of calcium carbonate, which led to the belief that these varieties are resistant to calcareous chlorosis. Plant height, wet weight and dry weight were significantly increased in the Ammonium sulfate treatment compared to the rest of the treatments. Where the average height of the plants in the Ammonium sulfate fertilization treatments with the two cultivars Dina F1 and Fahaa at the three carbonate ratios was higher compared to the rest of the studied treatments, and the highest wet weight and dry weight of the plants was in the Ammonium sulfate treatment at a content of 48% of calcium carbonate with Salmonia cultivar. The effect of the type of nitrogenous fertilizer used on the average weight and length of the cob and the number of grains per cob. The average length and weight of the cob and the number of grains per cob increased significantly in the Ammonium sulfate fertilization treatments compared to the control, as well as the effect of the soil content of total calcium carbonate on the characteristics of the grains in the cob, as the average number of grains increased. Significantly with the increase in the soil content of calcium carbonate, and the highest number of grains in earwigs at soil content was 68% (560.18 grains), followed by soil content 48% of calcium carbonate (513.08 grains), then when the soil content was 20% of calcium carbonate (477.33 grains). While the weight of the 100 grains decreased significantly with the increase in the soil content of calcium carbonate, the weight of the 100 grains increased significantly in the three fertilization treatments compared to the control, and the results indicate that the fertilization treatments of Ammonium sulfate were superior to the two fertilization treatments of potassium nitrate and urea, and the two cultivars were superior to Dina F1 and salmonia on the cultivar Fayhaa in terms of average productivity per hectare by 38% and 42.5%, respectively, where the average productivity in the cultivar Salmonia was (13.2 tons/ha), and in the cultivar Dina F1 (12.78 tons/ha), while it was in the cultivar Fayha (12.78 tons/ha). 9.26 tons/ha). The average productivity increased significantly when using Ammonium sulfate fertilizer by 14% compared to the control, and the highest values for the average productivity were when the soil content was 48% of calcium carbonate (13.74 tons / h). and the highest values for the average productivity were at the cultivar Dina F1, with the fertilization treatments of Ammonium sulfate (14.04 tons/ha).