| Abstract: |
Two field experiments were performed during two seasons 1996 and 1997 in Sakha agricultural research station, Kafr El Sheikh Governorate.Field experiment I:The purpose of this experiment was to study the effect of soil moisture content on the efficiency of injected anhydrous ammonia (AA) as fertilizer for maize crop. AA was injected into the soil 15 cm deep with 30 cm spacing between lines of injection.The Injection of AA was done immediately before cultivation. Three soil moisture content were tested, i.e., 10, 13 and 15% using two rates, 90 and 120 kg N/fed.The obtained results coulJ be summarized as follows:(I) Dry matter yield increased at 120 kg N/fed than at 90 KgN/fed. Increasing nitrogen fertilization rate was more pronounced at 13% soil moisture content compared to the two other soil moisture regimes.(2) Dry matter of leaves, stems and stalks were lower at 15% soil moisture level than at 10%, but grains showed the opposite trend. Highest values occurred with 13% moisture regime.(3) Addition of 120 kgN/fed showed greater uptake ofN, P and K by maize organs than the rate of 90 kgN/fed. the increases in N, P and K uptake as affected by soil moisture level can be arranged as following order: 13 > 15 > 10%. The highest yield and uptake was with 120 kg N/fed combined with the 13% soil moisture regime, while the lowest values were associated with the treatment of 90 kg N/fed and 10% soil moisture level.(4) Increasing N application led to increase the protein yield and total carbohydrate yield in grains. Increasing N rate increased protein concentration, while the carbohydrate concentration showed the opposite trend. 15% soil moisture level led to decrease the values of carbohydrate compared with 10% soil moisture level. Highest values occurred with 13% moisture level.(5) The yields of protein and total carbohydrate were highest with the addition of 120 kg N/fed combined with 13 % soil moisture level, and the lowest were obtained with 10% soil moisture level and 90 kg N/fed.(6) Increasing N rate increased available-N remained in soil throughout the two studied seasons. Increasing soil moisture up to 13% showed the highest residual N in soil. Increasing soil moisture level up to 15% showed greater available N compared with 10%.(7) The residual N in soil was highest with the combination between 13% soil moisture level and 120 kg N/fed, while the lowest values obtained with the treatment of 15% soil moisture level and 90 kg N/fed.Field experiment II:The experiment was carried out to compare the efficiency of injected anhydrous ammonia (AA) 82% N with three solid nitrogen feritlizers i.e., urea (D) 46.5% N, calcium ammonium nitrate (CAN) 33.5% N, ammonium sulphate (AS) 20.6% N. N was applied at two rates 90 and 120 kg N/fed.The solid N sources were applied into three equal doses during the two seasons, the first dose was applied after planting and the second one was applied before the first irrigation (21 days after seeding) while the last dose was applied before the second irrigation (36 days after seeding).The results may be summarized as follows:(1) Nitrogen source as anhydrous ammonia (AA) showed the greatest growth and yield while the lowest effective source was urea (U) as shown from the following order:Anhydrous ammonia (AA) > calcium ammonium nitrate (CAN) > ammonium sulphate (AS) > urea (U).(2) The greatest dry yield of all organs was associated with the addition of AA at a rate of 120 kg N/fed, while the lowest yield was given by U at 90 kg N/fed.(3) Increasing the rate of added nitrogen increased nitrogen uptake by all organs of plant. N-uptake values were in lines with the values of dry matter yield, the sequence of increase was as follows:(4) The combined effect between N-sources and rates showed that the highest N, P, and K uptake plant was associated with the addition of AA at the rate of 120 kg N/fed, whilethe lowest values of N uptake was associated with the application of urea at 90 kg N/fed.(5) The highest proteiln yield was associated with the addition of AA at 120 kg N/fed, while the lowest value was associated with the addition of urea at a rate of 90 kg N/fed.Increasing N rate increased yield of protein and carbohydrate in grains. The lowest value of carbohydrate yield was found with urea at a rate of 90 kg N/fed, while the highest value was with AA at the rate of 120 kg N/fed.(6) Increasing N-rate added to the soil resulted in greater content of available N in soil. The highest values through the two studied seasons were associated with AA followed by CAN and AS, and urea gave the lowest value.
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