Investigating on the relationship between plant measurements of Parapholis incurva with environmental factors and water point distance in rangelands of Incheh Borun Golestan province (case Study: Incheh Borun)

Abstract

Introduction: Parapholis incurva is a plant in halophytic rangelands of the northern Golestan Province and is very important in terms of forage production. This plant species grows in arid climates and saline soils. The aim of this study was to investigate the relationship between the characteristics of this species with environmental factors such as soil physicochemical properties and distance from the watering trough in rangelands of Incheh Borun in Golestan Province.Material and methods: Towards this attempt, 200 quadrates with an area of 4 m2 were taken along distances from a watering trough. The sampling method was randomized-systematic. In the sampling area, the presence of P. incurva species was recorded. In the center of each plot, the soil was sampled from depths of 0 to 20 centimeters. Soil samples were transferred to the laboratory and experiments were carried out to measure pH, electrical conductivity (EC), soil texture (silt, clay, and sand), organic carbon, nitrogen, and phosphorus. In this research pH, EC, soil texture, organic carbon, nitrogen, and phosphorus were measured using pH meter, conductivity meter, hydrometric method, and Olson method, respectively. Multiple regression analysis (using SPSS software V18) was used to investigate the relationship between the characteristics of P. incurva and distances from a watering trough and soil physicochemical properties. Results and discussion: R2 values (93%) showed that distances from a watering trough had the most contribution to the variations in density, percentage cover, and frequency changes. The strength of the linear regression model by soil parameters for predicting the density, percentage cover, and frequency of P. incurva was 77, 70 and 83 percent, respectively. Results showed soil properties such as total nitrogen, sand content, and organic matter content had a positive effect on the presence of P. incurva in the study area. The results showed that pH, Buckley density, silt content, and EC had a negative effect on the presence and distribution of P. incurva.Conclusion: On a local scale, distance from a watering trough was more influential on the changes in density, percentage cover, and frequency of P. incurva than soil parameters.

Keywords

• response curve
• parapholis incurve
• environmental gradients
• function hof