تقييم صور و جاهزية البوتاسيوم بتأثير اضافة الاسمدة البوتاسية و العضوية و الري الناقص في ظروف زراعية

Abstract EN

A field experiment was carried out in the Research Station of Al Suwaira, Agricultural Research Directorate-Ministry of Agriculture in silty clay soil, to study the availability of potassium forms in the soil and Evaluation level of availability of the plant, using three levels of potassium sulfate fertilizer (0, 100 and 200) kg.

ha-1 symbolized as K0, K1, K2 respectively, and the amount of fertilizer added was divided during the period of emergence, vegetative growth, and the beginning of flowering.

In addition to, three levels of organic fertilizer (0, 1% and 2% ) symbolized as M0, M1, M2 respectively, organic fertilizer was added to the top layer of the soil while preparing the experiment plots, and deficit Irrigation, where T1 (regular irrigation according to crop water requirements when 50% of available water is depleted) and T2 (skip one irrigation during each of vegetative, and flowering periods), and T3 (skip one irrigation during each of initiation, vegetative, and flowering periods).

The experiment was conducted according to Randomized Complete Block Design (RCBD) with three replications.

Maize crop Var.

5018 was planted on 25/7/2018.

Soil samples and plant samples were taken at vegetative growth and the ripening stage of the crop, soluble and exchangeable potassium for the first stage were estimated, and non-exchangeable potassium during the second growth stage.

The results showed: potassium and organic fertilizers treatments (K2 and M2) gave the best rates for the soluble potassium values, these rates decreased during the maturity of the crop compared to the vegetative growth stage.

These suitable fertility at the appropriate moisture stress limits exceeded the achievement of levels exchangeable and non- exchangeable potassium for the vegetative and maturity stages of the crop.

When evaluating the state of potassium and its availability in the soil before planting using some thermodynamic criteria, it was found that by adopting the activity standard for potassium, apportion and its percentage of 16–18% of soluble potassium in the soil solution is chemically ineffective.

It was also found that the negative values of the free energy of replacement fall within the medium-availability soils of potassium, It has also been found that the Potassium ionic activity are low for these soils, So it can be indicated the level of actual exploitation of these lands before planting.

While it became clear the role of the irrigation deficit treatment (T3) in reducing the ionic activity values of potassium, on the contrary, the role of fertilizer additives (mineral and organic) increasing the values of this indicator compared to the control treatment.

It was also worth noting that there has been a decrease in the ionic activity of potassium at the ma-turity stage of the crop as compared to the vegetative growth stage, and there was a significant increase in the negative values of free energy with the progress of the growth stages of fertilized and non-fertilized treatments, while there was a decrease of these values with the increase in the levels of Potassium and Organic fertilizers.