The quantity/intensity relation is affected by chemical and organic P fertilization in calcareous soils

Soil physicochemical (colloidal) properties affected by ozonated water and organic fertilization

More has to be investigated on the use of ozonated water (O3) for the improvement of growth medium properties. Accordingly, the objective was to examine the effects of O3 (control, 0.5, 1.0, and 2.0 mg L-¹) on soil physicochemical (colloidal) properties using organic fertilization (manure), under non-planted or planted conditions. Different soil physicochemical (colloidal) properties including soil available water (SAW), aggregate stability, soil porosity, pH, salinity (EC), organic carbon (SOC), CaCO₃, and cation exchange capacity (CEC) were determined. The experimental treatments and their interactions significantly (P ≤ 0.05) affected soil physicochemical properties including SAW (4.17-10.98%), aggregate stability and porosity (7.77-57.37%), SOC (0.15-2.09%), and CEC (17.68-42.75 Cmol( +)/kg). Interestingly, the single use of O3 or in combination with manure significantly decreased EC. Although O3 significantly decreased SOC in non-planted soils, it significantly increased SOC in planted soils. O3 may enhance soil physicochemical (colloidal) properties, and if combined with manure in a planted soil, such positive effects may be further enhanced.

Enhanced nutrient uptake in salt-stressed Mentha piperita using magnetically treated water

The improvement of the growth and quality of medicinal plants under stress is of significance, worldwide. The hypothesis was to alleviate salinity stress in Mentha piperita by enhancing nutrient uptake using magnetically treated water, which to our knowledge has not been previously investigated. The objective was to test the effects of magnetized water (using alternating magnetic fields) (main plots, M1-M4 representing control, 100, 200, and 300 mT, respectively), salinity (subplots, S1-S4 representing control, 40, 80, and 120 mM NaCl, respectively), and growth medium (sub-subplots, X1-X4 representing coco peat, palm, coco peat + perlite, and palm + perlite, respectively) on M. piperita nutrient uptake in the greenhouse. The M treatments, especially the 100 and 200 mT levels, significantly increased plant N (1.08%, S3M4X1), P (0.89%, S3M3X1), K (3.23%, S3M3X1), Ca (53.6 mg/kg, S4M4X4), and Mg (39.63 mg/kg, S3M3X2) concentrations (compared with control at 0.71, 0.49, 2.4, 26.63, 1.63) even at the highest level of salinity. Magnetically treated water also significantly enhanced plant Fe and Zn concentration to a maximum of 750 μg/kg (M4S3X1) and 94.67 μg/kg (S4M4X3), under salinity stress, respectively. The single and the combined use of organic and mineral media significantly affected plant nutrient uptake, especially when used with the proper rate of M treatment. If combined with the proper growth medium, the magnetized water may be more effective on the alleviation of salt stress in Mentha piperita by enhancing nutrient uptake.

Sunflower (Helianthus annuus L.) biochemical properties and seed components affected by potassium fertilization under drought conditions

The seed yield and healthy oil in sunflower (Helianthus annuus L.), as an important industrial crop, decrease under stress. There is not much investigation, to our knowledge, on the use of potassium fertilization, a regulator of plant water potential, affecting the biochemical properties and seed components of sunflower under drought stress. Accordingly, such parameters were investigated in a split-split plot field experiment, conducted in two different field sites (Natanz (Nt) and Eghlid (Eg), Iran), using potassium fertilization (subplots, 0, 150 and 300 kg/ha) and six drought levels (main plots) in four replicates. Although stress significantly affected sunflower biochemical properties and seed components in the two fields, the effects of stress were more pronounced in the Eg site (significant interaction of field and drought). The plant alleviated the stress by increasing the proline, oleic and linoleic acid concentrations, however, potassium fertilization also increased plant tolerance further under stress by enhancing such components compared with control. Interestingly, the Eg site was more responsive to the potassium fertilization (significant interaction of field and fertilization), as the fertilizer resulted in a higher rate of plant biochemical properties and seed components. The use of potassium fertilization at 300 kg/ha (K3) was the most effective treatment in the alleviation of stress. Interestingly, under drought stress, potassium contributed to the enhanced quantity and quality of sunflower by increasing seed components, and enhancing the biochemical properties of the plant, which can also improve crop physiological mechanisms. The results can further increase our understanding related to the effects of potassium fertilization on the yield and physiology of sunflower under drought stress. Such results are of economic, environmental and health significance.

Beetroot mineral composition affected by mineral and organic fertilization

In modern agriculture, besides providing high and stable yields, it is imperative to produce products with a high nutritive quality. The goal of this study was to determine the effect of different fertilization regimes on the macro- and micronutrients in beetroot. A 3-year field trial was set up according to a Latin square method with four types of fertilization (unfertilized control, 50 t stable manure ha⁻¹, and 500 and 1,000 kg NPK 5-20-30 ha⁻¹). The mineral content was determined as follows (mg 100 g⁻¹ in fresh weight of beetroot): 14–29 P, 189–354 K, 18–34 Ca, 17–44 Mg, 0.67–1.83 Fe, 0.41–0.65 Mn and 0.28–0.44 Zn. The highest beetroot P content was determined for the treatment with stable manure, especially in a year with dry climatic conditions. The highest beetroot K content was determined for the treatment with 1,000 kg NPK 5-20-30 ha⁻¹, but at the same time for the same treatment, a general decreasing trend of micronutrient content was determined, due to the possible antagonistic effect of added potassium. For better mineral status of beetroot, application of combined mineral and organic fertilizers supplemented with additional foliar application of micronutrients can be suggested.