Response Of Wheat Plant Grown In Calcareous Soil To Nitrogen, Biological And Organic Fertilization Under Different Irrigation Conditions
إبراهيم حسين السكري, أحمد إسماعيل أحمد عبد العال, حسين الظاهر جمعة, عبد العزيز بسيوني المنشاوي
كلية الزراعة-جامعة الاسكندرية · مصر
The study included two groups of field experiments: Effects of irrigation, nitrogen, and biofertilizer on soil and plant. Effect of irrigation, nitrogen, and farmyard manure on soil and plant. These experiments were planned as follows: The main treatment was the irrigation regime: i. Normal irrigation (NI), which received 100% of the ETpan, and the number of irrigations was seven. ii. Deficit irrigation (DI), which was carried out by reducing the number of irrigations to five. The sub-main treatments were nitrogen fertilizer application: Nitrogen fertilizer was applied at the following three rates: i. N0: the control ii. N30: application of 30 kg N/fed iii. N60: application of 60 kg N/fed iv. N90: application of 90 kg N/fed The sub-sub main treatments included two different fertilizer sources: i. Biofertilizer (B): Biofertilizer treatments included untreated seeds (B0) and treated seeds (B1) with serialin (for the first experiment). ii. Farmyard manure (FYM): The treatments were without (FYM0) and with 20 m³/fed treatments (FYM1) application (for the second experiment). The experimental design was split-split plots with four replicates. Treatments of the first experiment were irrigation, nitrogen, and biofertilizer treatments, and of the second experiment were irrigation, nitrogen, and farmyard manure treatments. The area of the plot was 7m * 6m (42m²). The seeds of wheat were planted in December 2007 and harvested in May 2008. The base fertilization of all soil plots was carried out during land preparation with the application of superphosphate fertilizer (12.5% P₂O₅) at a rate of 30 kg P₂O₅/fed, and potassium sulphate (49% K₂O) at a rate of 24 kg K₂O/fed. Irrigation was carried out using fresh water from the El-Nubaria canal. Sampling of soils (0-20 cm, 20-40 cm, 40-60 cm) was carried out before cultivation, after 30 days, 75 days, and 152 days from planting, and before each irrigation to determine moisture content. These samples are defined as at tillering, heading, and harvest growth stages. The soil chemical analyses were carried out for the determination of the amounts of available macronutrients (N, P, and K). The soil biochemical analyses were carried out to determine the SMBC, SMBN, and SR. Sampling of plants was carried out at the three growth stages for the determination of growth parameters: fresh weight, dry weight, straw, grain yields, and also the concentrations of N, P, and K in plant organs. Fertilizer nitrogen use efficiency (FNUE), nitrogen utilization efficiency (NUtE), nitrogen harvest index (NHI), irrigation water utilization efficiency (IWUtE), and water use efficiency (WUE) were calculated. The obtained results were statistically analyzed using SAS Software Statistical Packages and are summarized in the following paragraphs. 5.1 Effect of Irrigation, Nitrogen, and Biofertilizer (The First Experiment): 5.1.1 Effect of Irrigation and Nitrogen: The results obtained showed significant increases in the amounts of available N in soil samples collected at tillering, heading, and harvest growth stages with increasing rates of applied N. The amount of available N was generally higher in soil samples of the upper layer than in those of the lower layer. However, there were no significant interaction effects between rates of applied N and irrigation (NI and DI) treatments on the amounts of available N in soil samples at the three growth stages. The amounts of available N in soil samples decreased with proceeding plant growth and were, as overall mean values, 44.8, 39.2, and 33.6 mg N/kg in soil samples of the upper layer collected at tillering, heading, and harvest growth stages, respectively. The results showed no significant variations in the amounts of available P, K, and the amounts of O.M. in soil samples with nitrogen and irrigation treatments at the three growth stages. The results showed significant increases in the levels of SMBC, SMBN, and SR with increasing rates of applied N for both soil samples of the upper and lower layers collected at the three growth stages. It is also clear that the levels of SMB, in general, were almost higher in soils of the upper layer than in those of the lower layer. The data also showed that higher levels of SMBC were found in soil samples collected at heading (overall mean value of 314.5 mg C/kg soil) than at tillering (overall mean value of 294.8 mg C/kg soil), while those at harvest were the lowest (overall mean value of 170.5 mg C/kg soil). The levels of SMBN were the highest in soils collected at tillering (overall mean value of 173.8 mg N/kg soil) and the lowest at harvest (overall mean value of 82.3 mg N/kg soil), while at heading, they were moderate (overall mean value of 123.9 mg N/kg soil). The results also showed significant increases in the levels of SR with increasing rates of applied N, and these levels were higher in soil samples of the upper layer than in those of the lower layer. Also, there were no significant variations in the levels of SR due to irrigation regime treatments. The data also showed that the levels of SR were higher at heading (overall mean value of 160.5 mg C/kg soil) than at tillering (overall mean value of 137.9 mg C/kg soil), while those at harvest were the lowest (overall mean value of 111.6 mg C/kg soil). The fresh and dry weights of the above-ground parts of wheat plants at tillering and harvest growth stages increased significantly with increasing rates of applied N. In addition, there were significant interaction effects between rates of applied N and irrigation treatments on the dry weights of wheat plants at the three growth stages. However, plants subjected to deficit irrigation (DI) had lower values than those subjected to normal irrigation (NI). The straw and grain yields significantly increased with increasing rates of applied N, and there were significant interaction effects between N application and irrigation regime treatments on the straw and grain yields. The straw and grain yields were significantly higher with NI treatment than with DI treatment. There were significant increases in the concentrations of N, P, and K in the above-ground parts of wheat plants at the three growth stages with increasing rates of applied N. There were significant interaction effects between irrigation treatments and N application on the concentrations of these elements in plants. There were also significant increases in the concentrations of N, P, and K in the grain of wheat with increasing rates of applied N. However, there were no significant interaction effects between N application and irrigation treatments on the concentration of N and P in the grain. These results also indicated that the uptakes of N, P, and K by the straw and grain increased with increasing rates of applied N. There were pronounced decreases in the values of FNUE and NUtE by wheat plants with increasing rates of applied N. However, there were no marked variations in the values of NHI with increasing rates of applied N. In addition, the values of FNUE were generally higher with NI plants than DI plants, while the opposite was found with NUtE, while there were no marked variations between NI plants and DI plants for NHI. With respect to IWUtE, their values increased with increasing rates of applied N from 0.50 kg grain/m³ (N0 treatment) to 1.14 kg grain/m³ (N90 treatment). The values of IWUtE were generally higher with DI (mean value of 0.89 kg grain/m³) than NI (mean value of 0.83 kg grain/m³) treatments. Also, the values of WUE increased with increasing rates of applied N from 0.88 kg grain/m³ (N0 treatment) to 1.90 kg grain/m³ (N90 treatment). The values of WUE were generally higher with DI (mean value of 1.29 kg grain/m³) than NI (mean value of 1.47 kg grain/m³) treatments. 5.1.2 Effect of Irrigation and Biofertilizer: The results showed no significant increases in the amounts of available N, P, and K in soils collected at the three growth stages due to irrigation treatment and biofertilizer application. Also, there were no significant interaction effects between irrigation treatments and biofertilizer application on the amounts of available N, P, and K in soil samples. The results also showed no significant increases in the amounts of O.M. in soil samples due to irrigation regime treatments and biofertilizer application. Also, there were no significant interaction effects between irrigation and biofertilizer treatments on the amounts of O.M. in soils. With respect to SMB, there were significant increases in the levels of SMBC, SMBN, and SR as a result of irrigation and biofertilizer treatments in soil samples collected at the three growth stages. However, there were no significant interaction effects between irrigation regime and biofertilizer treatment on SMBC, SMBN, and SR. It is clear from the obtained results that the levels of SMBC, SMBN, and SR were almost higher in soil samples of the upper layer than in those of the lower layer. The results also showed that the level of SMB was influenced by the growth stage of wheat plants. Thus, the levels of SMBC were higher in soil samples (0-20 cm) collected at heading (mean values of 314.5 mg C/kg soil) than at tillering (mean values of 294.8 mg C/kg soil), while those at harvest were the least (mean value of 170.5 mg C/kg soil). On the other hand, the levels of SMBN in soil samples of (0-20 cm) collected at tillering were higher (mean values of 173.9 mg N/kg soil) than those at heading (mean values of 123.9 mg N/kg soil) and at harvest (mean value of 82.3 mg N/kg soil). However, the levels of SR were higher in soil samples (0-20 cm) collected at heading (mean value of 160.5 mg CO₂/kg soil) than at tillering (mean value of 137.9 mg CO₂/kg soil) and at harvest (mean values of 111.6 mg CO₂/kg soil). The results showed no significant variations in the concentrations of N, P, and K in the above-ground parts of plants at the three growth stages as a result of irrigation and biofertilizer application. The same effects were found with respect to the concentration of N, P, and K in the grain. The amounts of N, P, and K uptake by straw and grain increased markedly with biofertilizer application and were higher in plants subjected to NI than DI irrigation. The values of IWUtE were markedly higher in plants subjected to DI than in plants subjected to NI. There was also a marked effect due to biofertilizer application on IWUtE (mean value of 0.88 kg grain/m³) as compared with the untreated (mean value of 0.84 kg grain/m³). Also, there were marked effects of biofertilizer treatments on the values of WUE. As mean values, it increased from 1.29 kg grain/m³ (FYM0) to 1.48 kg grain/m³ (FYM1). 5.1.3 Effect of Nitrogen and Biofertilizer: The obtained results showed significant increases in the amounts of available N in soil with increasing rates of applied N, while those of P and K were not significantly affected. This has been found in soil samples of the upper and lower layers. Also, there were no significant interaction effects between nitrogen and biofertilizer treatments on the amounts of available N, P, and K in soil. There were no significant variations in the amounts of O.M. due to the application of nitrogen and biofertilizer in both soils of the upper and lower layers. The results showed significant increases with increasing rates of applied N and biofertilizer treatment. The levels of SMBC were almost higher in soil samples of the upper layer than in those of the lower layer. The highest levels of SMBC were recorded in soil samples at the heading growth stage (mean value of 314.5 mg C/kg soil), while the lowest were found in soil samples at harvest (mean value of 170.5 mg C/kg soil), and the moderate at tillering (mean value of 294.8 mg C/kg soil). There were positive significant interaction effects between N application and biofertilizer treatment on the levels of SMBC in soil samples of the upper layers. It is generally clear that biofertilizer treatment significantly increased the level of SMBC from 207.0 to 382.6, from 215.2 to 413.7, and from 114.5 to 226.5 mg C/kg soil at tillering, heading, and harvest growth stages, respectively. The levels of SMBN increased significantly with increasing rates of applied N and were higher in soil samples of the upper layer than in those of the lower layer. Also, biofertilizer treatment significantly increased the levels of SMBN in the upper layer. There were no significant interaction effects between N application and biofertilizer on the levels of SMBN in the upper layer. The levels of SR significantly increased with increasing rates of applied N in both soil layers. However, there were no significant effects on the level of SR due to biofertilizer treatment. There were also no significant interaction effects between N application and biofertilizer treatment on the level of SR. The results also showed that the levels of SR were generally higher at heading than at harvest and moderate at tillering growth stage. The results obtained showed that the fresh, dry weight, straw, and grain yield of wheat plants had significantly increased with increasing rates of applied N. However, there were significant interaction effects between N application and biofertilizer treatments on the fresh and dry weights of plants at the three growth stages, and also, there were significant interaction effects between N application and biofertilizer on the straw and grain yield of wheat. The concentrations of N, P, and K in the above-ground parts of plants increased significantly with increasing rates of applied N. There were positive significant variations of N concentration in plants due to N application treatments at the heading growth stage. Also, the concentration of N, P, and K in the grain increased with increasing rates of applied N, while there were no significant effects due to biofertilizer treatments. The amounts of N, P, and K taken up by wheat plants increased with increasing rates of applied N, in both straw and grain. Biofertilizer treatments improved the concentrations of N, P, and K in grain, while this effect was not clear in straw except with K. However, the total N, P, and K uptake in plants was markedly increased with biofertilizer treatment. 5.2 Effect of Irrigation, Nitrogen, and Farmyard Manure (The Second Experiment): 5.2.1 Effect of Irrigation and Nitrogen: The obtained results showed that the application of N fertilizer significantly increased the amount of available N in soil samples at the three growth stages of wheat plants. However, there were no significant effects between N application and irrigation treatments on the amounts of available N in soils. It is also clear that the amount of available N in soil samples decreased with proceeding plant growth. The results also showed that the application of N fertilizer had no significant effects on both the amounts of available P and K and the amounts of O.M. in soil samples at the three growth stages of wheat plants. On the other hand, soil microbial biomass expressed as SMBC, SMBN, and SR significantly increased with N application. However, there were no significant interaction effects between N application and irrigation treatment on the levels of SMB in soil samples at the three growth stages of wheat plants The level of SMB was almost higher in soil samples of the upper layer than in those of the lower layer. The levels of SMBC were higher in soil samples at heading than at tillering and harvest growth stages (mean values of 315.2, 288.6, and 202.0 mg C/kg soil, respectively). The same trend was found for SR. However, the levels of SMBN were higher at tillering than at heading and harvest. The fresh and dry weights of wheat plants increased significantly with increasing rates of applied N with NI and DI irrigation. There were also significant interaction effects between N application and irrigation treatments on the fresh and dry weights of wheat plants at the three growth stages. The same effects were recorded for straw yield and grain yield. The results showed that the application of N fertilizer significantly increased the concentration of N in the above-ground parts of plants at the three growth stages. However, there were no significant interaction effects between N application and irrigation treatments on the concentration of N in plants. Also, the application of N had no significant effects on the concentration of P and K in plants at tillering and heading growth stages. Also, the application of N fertilizer significantly increased the concentration of N, P, and K in the grain of wheat. However, there were no significant interaction effects between N application and irrigation regime treatments on the concentration of these elements in the grain. The amounts of N, P, and K taken up by the straw and grain markedly increased with increasing rates of applied N. It seems also that NI irrigation increased nutrient contents in the straw and grain, which were markedly higher than those of plants subjected to DI irrigation. The values of fertilizer nitrogen use efficiency (FNUE) of wheat plants decreased with increasing rates of applied N from 55.3 to 27.4 with N30 to N90 in plants subjected to NI and decreased from 46.0 to 23.6 with N30 to N90 in plants subjected to DI irrigation. This points out the role of N in improving FNUE under deficit irrigation. Also, the values of NUtE decreased with increasing rates of applied N with NI and DI irrigation. However, the values of NUtE were higher in plants subjected to DI than to NI at each rate of applied N, which were 54.7 and 50.2, 47.8 and 43.4, 46.3 and 42.2, and 45.1 and 42.2 with N0, N30, N60, and N90 treatments, respectively. Nitrogen harvest index (NHI) of wheat plants increased with NI irrigation from 70.2 (N0 treatment) to 73.5 (N90 treatment), while at DI irrigation, these values increased from 70.1 (N0 treatment) to 73.1 (N90 treatment). The data showed the role of N under irrigation deficit for improving N fertilization by plants. The values of IWUtE increased with increasing