Variability Assessment of Macro Element Contents in Pasture Plants in Response to Plant Growth (The Case Study of Nomadic Grasslands of North Khorasan Province)

Organisms need a variety of mineral nutrients for their normal functioning; some of these nutrients are needed in large quantities, while others are less essential. In this study, the effect of plant growth on macro mineral contents of the important plant species of nomadic grasslands of North Khorasan province was studied. Random sampling of dominant species in upland, lowland, and intermediate ranges was conducted at three phenological stages: vegetative growth, flowering, and seeding. For each species and at each growth stage, five randomly selected samples were chosen from different parts of the vegetation types, with each sample containing three individual plants. Data analysis was performed using one-way analysis of variance and Duncan test to track the inter-group changes. The amount of theseelements was compared to their critical levels to meet the animal unit maintenance needs using T-test. The results showed that in general, the amount of every macro nutrient is more at the vegetative stage in comparison to the seeding stage. In addition, their values in each of the growth stages were different between the studied species. The analysis of the macronutrients of the studied species at different regions indicated that in all three types of the studied grasslands, the species had more phosphorus, potassium, and calcium and less sodium, magnesium, and calcium/magnesium ratio than the average need of livestock at all stages of growth.