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Çankırı Karatekin Üniversitesi (2021)

Semi-arid and semi-humid climate in the pasture, plant and soil analysis of the interaction of multiple properties relationships

YILMAZ Ülkü

Titre : Semi-arid and semi-humid climate in the pasture, plant and soil analysis of the interaction of multiple properties relationships

Yarı kurak ve yarı nemli meralarda iklim, bitki ve toprak özelliklerinin çoklu etkileşimlerinin analizi

Auteur : YILMAZ Ülkü

Université de soutenance : Çankırı Karatekin Üniversitesi

Grade : Doktora Tezi 2021

Résumé
Sustainable management of grasslands is important to maintain their productivity and save those invaluable resources for the future generation. Spatial variability of soil and plant resources in the grasslands may provide proficiency for their sustainable planning and management. This study aimed at an in-depth evaluation and compare two different grasslands (a semi-arid and a semi-humid grassland) spatial variability of soil properties and plant nutrient concentrations. Also, differences in associations between soil and plants in nutrient concentrations were evaluated. Two representative grasslands were chosen in Kurşunlu (semi-arid) and Ilgaz (semi humid). Randomly selected sampling sites of 1 × 1-m were determined at 400 points on each of the grasslands. Undisturbed and disturbed soil samples were taken from 0-10 and 20-20 cm soil depth at each of sampling sites. Soil bulk density and field capacity were determined in those undisturbed soil samples. Disturbed soil samples were taken from 0-10 and 10-20 cm ; five samples were taken (at the corners and the middle of the representative area) at each sampling area ; the samples were mixed and then a representative composed sample is taken from the bulk. Soil water content at sampling, total porosity, wilting point, plant available water content, aggregate stability, CaCO3 content, organic matter (OM) content, pH, electrical conductivity (EC), cation exchange capacity (CEC), sand, clay, silt contents, and concentrations of macro (Ca, Mg, K, P) and micro (Fe, Cu, Mn, Zn) nutrients were determined in composed soil samples. Also, plant samples were collected at each sampling site and nutrient concentrations (Ca, Mg, K, P, Fe, Cu, Mn, Zn) were determined in plant samples. Penetration resistance of soils was measured during the sampling. Data were evaluated using both classical statistical and geostatistical methods. Differences in soil properties between depth and between grasslands were evaluated by multiple analysis of variance MANOVA). Relationship between nutrient concentrations in soil and plants were analyzed by Sperman’s correlation analysis. Spatial structure of soil properties and plant nutrient concentrations were modelled by semivariograms and their surface maps were built by ordinary kriging interpolations. Most of the soil properties and plant nutrient concentrations were significantly varying between the grasslands. The relationships between soil and plant nutrient concentrations were highly different between to grasslands. Considerably different spatial structures for soil and plant nutrient concentrations occurred in the grasslands. Two grasslands were highly different in model type, range, and nugget effect for the soil properties and plant nutrient concentrations. Geostatistical range was generally lower in semi-humid grassland. Surface maps of the soil variables showed that spatial pattern of the variables were more patchily in semi-humid grassland. The results showed that plant nutrient concentrations may show substantially high spatial variability even in a small area, suggesting necessity of site-specific management of study grasslands. Results of this study may be used to develop series of studies toward evaluating grassland resources for the purpose of developing plans for sustainable grassland management via managing grasslands site-specifically across Turkey.

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Page publiée le 4 janvier 2023