Showing 2 results for M. Samavati
M. Samavati, Hosseinpur,
Volume 15, Issue 55 (spring 2011)
Abstract
Phosphorus is often considered the most limiting soil nutrient for plant productivity. Several extractants have been typically used to measure available P. Organic and inorganic P fractions are not measured by common soil test, and thus fractionation schemes using various extractants have been developed over years to quantify the different chemical forms of P in soils. The objectives of this research were: i) to investigate the effect inorganic P fractions on Phosphorus availability ( Olsen procedure), and ii) to evaluate the relationships between these P fractions and Garlic (Allium sativum) plant indices. Soil inorganic P fractions were determined in 30 surface soil samples (0-30 cm) from various regions of Hamedan Province. Inorganic P fractions included dicalcium phosphate (Ca2-P), octa calcium phosphate (Ca8-P), P adsorbed by Al oxide (Al-P), P adsorbed by Fe oxide (Fe-P), P incorporated into Fe oxide (O-P), and apatite (Ca10-P). Total P and Organic P were measured in these soils. In order to evaluate the availability of different forms of P to plant, a pot experiment was conducted on Garlic plant. The treatments including two rates of P (zero and 150 mg kg-1) and 9 soils from 30 soil samples were arranged in a factorial experiment in a completely randomized design with three replicates. The results showed the total P with an average of 1501 mg kg-1 soil, and organic P comprised 19 % of the total P. The inorganic P fractions (Ca2-P), (Ca8-P), (Al-P), (Fe-P), (O-P), (Ca10-P) and residual phosphate (Res-P) comprised 4.7, 20, 8.7, 3.0, 2.8, 24 and 18 % of total P, respectively. Most of the inorganic P occurred as Ca-P and comprised 49% of total P. The correlation study between different P fractions showed that Ca2-P, Ca8-P, Ca10-P, and Al-P were significantly correlated with Olsen-P. This suggested that probably Olsen procedure essentially removed some P from these fractions. The results of pot experiment indicated that plant indices (relative yield and Yield efficiency) were significantly correlated with Ca2-P, Ca8-P and Olsen-P (P ≤ 0.05). P availability in the studied soils was influenced by Ca2-P and Ca8-P which could be used in a long period of time by plant.
M. Samavati, B. Eskandari,
Volume 17, Issue 63 (Spring 2013)
Abstract
Quantity-Intensity (Q/I) curves and their derived parameters provide general information about soil Potassium (K) availability. This investigation was conducted to obtain K different varieties and their correlations with K, Q/I parameters in 13 soils sample from Bahar area as the major potato producing area in Iran. Soil Samples were equilibrated with solution containing different potassium activity ratios (ARK), and changes in potassium concentrations in the equilibrium solution (ΔK) were ploted against activity ratio of K, and Q/I parameters were determined. The results showed that, potassium activity ratio at equilibrium (AR0) ranged from 0.007 to 0.995 with an average of 0.16 (mmol L-1)0.5, The readily exchangeable potassium (ΔK0) ranged from 0.04 to 2.199 with an average of 0.49 cmol kg-1, The potassium potential buffering capacity (PBCK) ranged from 13.21 to 75.37 with an average of 42.02 (mmol kg-1) / (mmol L-1)0.5. Highly significant linear correlations were found between PBCK and CEC (r = 0.6*), AR0 and KSO (r = 0.99**), AR0 and Kex (r = 0.85**). Among the studied soils, one soil (Chopolgh Lo soil) absorbed potassim on edge position of clay minerals and the others absorbed potassium on planar surface.
