سلوكية بعض أسمدة الحديد وأثزها في نمو وحاصل الذرة الصفزاء في تزبة كلسية

Abstract

This study was conducted in college of agricultural - university of Andar; including four experiments, three were laboratory experiments and one was field experiment. The aim is to study the behavior and efficiency of organic Fe fertilizer which was prepared from plant residues (peat moss) and iron metal compared to artificial chelating fertilizers of Iron metal iron fertilizers. Fulvic and Humic acid were extracted from peat moss to prepare chelating source of iron. Chelating fertilizer of Iron was made by adding the mineral source (FeSo4.7H2O) to the humic acid and fulvic to form Iron Humate and Fulvat (FeHA+FA). The first experiment was to incubate various iron sources to understand the physicochemical behavior of these sources whether it was metal (FeSO4.7H2O), artificial chelate (FeDTPA) or natural chelate (Fe HA+FA), where added to the soil and left to react for a period of time 1, 3, 6, 9, 12, 15, 20, 25, 30, 35, 40, 45, 50, 55 and 60 day. This experiment was applied in two replicate for each period, iron availability from these source was measured after each period in order to describe kinetic behavior of the element by using related kinetic equations and static indicators. The Second experiment laboratory applied in two replicates to find out the solubility product of iron sources in the soil. Iron sources used were added into two levels each 5 and 50 kg.h-1 in addition to the control level which was no iron added (0 kg.h-1 ). Incubation periods were 4, 20, and 40 days (wetting and drying periods of 1, 5, and 10 times). After each period of incubation time; water soluble iron was extracted by shaking 1:1 soil: distilled water, after filtration; soluble iron as well as available iron (extracted by DTPA) were determined using atomic absorption. Third experiment was to determine adsorption isotherm of iron in the soil, where fertilizer sources (mineral, artificial chelate and natural chelate) added into seven concentrations (10, 40, 80, 120, 200, 300 and 400) µg Fe ml-1 , and concentrations were replicated twice. Twenty ml of each concentration was added to 1 gm soil, adsorbed amount of iron was calculated and its indicators estimated using Langmuir equation. The field experiment was conducted in Silty Clay Loam soil using R.C.B.D design in three replicates during autumn season 2015 on 22/8/2015. Zea mays variety Baghdad 3 On 11/09/2015 iron sources were applied in four levels 0, 5, 10 and 15 kg h-1 and each level was replicated three times. The results showed that: Firstl: kinetic study. Available Iron concentrations decreased with time for all sources with high correlation of Linear equation. The linear equation was the best among other equations to show the relation between iron concentrations and time. Sources of b natural chelate and artificial chelate maintained available level of iron for two months compared to the mineral source of iron (FeSO4.7H2O). Second: Solubility product. 1- Solubility product results showed that the Siderite mineral (FeCO3) was controlling the original iron in the soil. 2- Source of natural chelate; Iron Humate + Fulvat (FeHA+FA) occupy solubility positions refers to the formation of less precipitation compositions and higher solubility in compression to other iron sources used in this study specially the mineral source (FeSO4.7H2O) which showed inability to maintain a balanced concentration of iron for long time. Third: Iron adsorption isotherm. 1- Appling the artificial chelating source of iron (Humate and Fulvat, FeHA+FA) reduced iron adsorption as applied concentrations increased in comparison to the mineral source (FeSO4.7H2O) and artificial chelating source (Fe DTPA). 2- Lowest adsorption capacity of iron reached 6200 mg kg-1 by applying artificial chelating source of iron (Humate and Fulvat) compared to the mineral source FeSO4.7H2O where adsorption capacity reached 7734.92 mg kg-1, while the artificial chelating (Fe-DTPA) was in the middle with adsorption capacity of 6800 mg kg-1 between the artificial chelating source and the mineral one. 3- The highest adsorption of iron was by applying it from mineral source with high bonding energy (K), while the artificial chelating source (Fe-DTPA) was in the middle between the natural and artificial source of iron in term of higher adsorption and linking energy. Fourth: The field experiment. 1- Applying artificial chelating source prepared of iron humate + fulvate showed significantly higher results in plant height, dry weight, plant grain yield, total grain yield and iron concentration in corn leaves and grain compared to the mineral source of iron and the artificial chelate. 2- The artificial chelating source (Fe-DTPA) was superior compared to the mineral iron (FeSO4.7H2O) for the all studied trails. 3- Iron fertilization caused an increasing in all studied traits compared to the control treatment (without iron)