الفهرس 
Responses of soil nitrogen and plant systems to organic compounds and zeolite mineralOnly 14 pages are availabe for public view
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Abstract
The current study involved different experiments, i.e. two laboratories experiments, one pot experiment and two field experiments to explore the impact of using some organic and inorganic compounds on the bioavailability of P and N as well as, to reduce losses of both nutrients by volatilization or leaching.
Results demonstrated that all of the different treatments markedly decreased nitrogen volatilization as NH3 compared to the untreated soil. The lowest loss was found by biochar + biofertilizer treatments.Whereas the application of potassium humate + biofertilizer treatment was the highest one. However, biochar + biofertilizer treatment was the most effective for reducing chemically available N-NO3 with increasing the depth up to 60 cm and this treatment was the most effective to control mobility and concentration of N-NO3 at depth 20 to 40 cm compared to the control. While, the application of biochar, zeolite+ biofertilizer or zeolite at the different rates appeared the lowest effect on the movement of NO3—ions. But, the application of potassium humate + biofertilizer at the different levels increased the mobility of P with depth compared to the control, on the other hand, potassium humate and potassium humate + biofertilizer increased the concentration of P with increasing time of experiment to 60 days then decreased with increasing the time.
Generally, the untreated soil contained P forms as follows: calcium bound (P-Ca)> reducible bound (OXD)> exchangeable (EXC)> organically bound (ORG) at the different depths and these fractions varied according to the studied treatments. Data also revealed that, the exchangeable P was higher with application of zeolite followed by biochar, biofertilizer and potassium humate treatments. The P-Ca was higher with application of zeolite followed by potassium humate, biofertilizer and biochar. While, the ORG-P was higher with application of biofertilizer followed by, biochar, potassium humate and zeolite treatments. The reducible bound P was higher with application of zeolite followed by, biochar, potassium humate and biofertilizer treatments in the low level at (0.5 %), but in the high level at (1%), it was higher with application of zeolite followed by, biochar, biofertilizer and potassium humate treatments. The soluble P forms were higher with application of biochar followed by zeolite, biofertilizer and potassium humate treatments at depth 20 cm. Concerning the effect of the different amendments on dry weight, N and P concentrations in corn and lettuce plants grown on the calcareous and sandy soils, results showed that the treatment of biochar + biofertilizer was superior in increasing plant growth and its content from the studied nutrients.
Keywords: Organic Compounds, Inorganic Compounds, N, P, bioavailability, Fractionation, Corn plant and lettuce plant.