Aggregate Stability and Water Retention near Saturation Characteristics as Affected by Soil Texture, Aggregate Size and Polyacrylamide Application
نویسندگان
چکیده
Understanding the effects of soil intrinsic properties and extrinsic conditions on aggregate stability is essential for the development of effective soil and water conservation practices. Our objective was to evaluate the combined role of soil texture, aggregate size and application of a stabilizing agent on aggregate and structure stability indices (composite structure index [SI], the α and n parameters of the VG model and the S-index) by employing the high energy (0–5·0 J kg ) moisture characteristic (HEMC) method. We used aggregates of three sizes (0·25–0·5, 0·5–1·0 and 1·0–2·0mm) from four semi-arid soils treated with polyacrylamide (PAM). An increase in SI was associated with the increase in clay content, aggregate size and PAM application. The value of α increased with the increase in aggregate size and with PAM application but was not affected by soil texture. For each aggregate size, a unique exponential type relationship existed between SI and α. The value of n and the S-index tended, generally, to decrease with the increase in PAM application; however, an increase in aggregate size had an inconsistent effect on these two indices. The relationship between SI and n or the S-index could not be generalized. Our results suggest that (i) the effects of PAM on aggregate stability are not trivial, and its application as a soil conservation tool should consider field soil condition, and (ii) α, n and S-index cannot replace the SI as a solid measure for aggregate stability and soil structure firmness when assessing soil conservation practices. Copyright © 2016 John Wiley & Sons, Ltd. key words: soil conservation; stable aggregates; pore size distribution; soil structure; retention curve
منابع مشابه
Study of Saturated Hydraulic Conductivity Variations in Different Aggregate Size Distributions in an Agricultural Soil
Saturated hydraulic conductivity (Ks) is one of the most important soil physical characteristics that plays a major role in the soil hydrological behaviour. It is mainly affected by the soil structure characteristics. Aggregate size distribution is a measure of soil structure formation that can affect Ks. In this study, variations of Ks were investigated in various aggregate size distributions ...
متن کاملComparing the Effects of Vetiver and Polyacrylamide on Soil Structural Stability and Erosion Indices
Extended abstract 1- INTRODUCTION Soil erosion is one of the most important problems of the environment, natural resources, and agriculture in the world. Soil structure stability is the key element of soil health, the main factor in the improvement or degradation of soils, and the important point in evaluating the effects of land management and the operations practices to control soil ero...
متن کاملارزیابی پایداری ساختمان خاک بهروش الک تر در برخی از مکانهای مرتعی استان اصفهان
Soil aggregate stability is considered as a key indicator of soil quality and health assessments in rangelands. Many factors and properties such as soil texture, organic carbon, calcium carbonate, sodium adsorption ratio, and electrical conductivity might affect soil aggregate stability. The effects of these factors on aggregate stability of 71 soil samples collected from 4 rangeland sites (2 i...
متن کاملمقایسه پایداری خاکدانههای خاک در شدتهای چرایی مختلف (مطالعه موردی: مراتع بردآسیاب فریدونشهر)
Soil quality, aggregate stability and erosion sensibility are affected by different range management practices. This research aimed to evaluate the relationships between soil organic carbon, mean weight diameter (MWD) and aggregate size distribution in the surface soil layer (0- 20 cm) of various range sites with different grazing intensities (non, slightly and heavily grazed) in Bardasiab ra...
متن کاملAggregate Size Distribution Indices Influenced by Different Types/Managements of Plant Residues under Field Conditions
1- INTRODUCTION Nowadays, environmental aspects of soil erosion are specifically considered by researchers. In this regard, secondary (aggregate) particle size distribution (SPSD) is so important in different issues such as nutrient loss, pollutant transport and carbon cycle. Aggregate size distribution is known as the representative of soil structure, which is by itself regarded as a dynami...
متن کامل