Are power laws that estimate fractal dimension a good descriptor of soil structure and its link to soil biological properties?

Abstract:The rice-wheat rotation system plays a significant role in Asian agriculture. The introduction of strip-tillage into the rice-wheat system for wheat planting offers a way to use conservation tillage practices to improve the seedbed quality, retain residue between rows and reduce energy input. A field experiment was conducted using an in-situ test rig. Three types of blade (bent C, straight and hoe) were evaluated in four tool configurations at four rotary speeds (180 r/min, 280 r/min, 380 r/min and 510 r/min) in a paddy soil. Furrow shape parameters, tillage-induced soil structures and energy consumption were assessed. Results showed that the straight blade configuration failed to create a continuous furrow at either 180 r/min or 510 r/min. The bent C blade configuration produced a uniform furrow profile but its furrow backfill was poor and unsuitable for seeding. The hoe blade configuration cut a continuous furrow and better tillage-induced soil structure, but it produced a much wider and non-uniform furrow shape. The mixed blade configuration (central hoe blades with two straight blades aside) provided a uniform furrow with good backfill and fine tilth by utilizing both the cutting effect of straight blades on the furrow boundaries and tensile fracturing of the furrow soil by the hoe blades. The torque of the mixed blade configuration was comparable with the bent C blade but was less than the hoe blades. Hence, a mixed blade configuration was recommended for rotary strip-tillage seeding using in rice-wheat system. Keywords: strip tillage, rotary strip-till tool, blade configuration, furrow quality, tilth, torque, rice-wheat rotation system DOI: 10.25165/j.ijabe.20181102.3347Citation: Yang Y S, Fielke J, Ding Q S, He R Y. Field experimental study on optimal design of the rotary strip-till tools applied in rice-wheat rotation cropping system. Int J Agric & Biol Eng, 2018; 11(2): 88-94.

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“…Mean Weight Diameter (MWD) was used to evaluate the degree of soil fragmentation induced by the strip-till tools using Equation (1) [30] .…”

Section: Soil Fragmentationmentioning

confidence: 99%

Field experimental study on optimal design of the rotary strip-till tools applied in rice-wheat rotation cropping system

Yang

Fielke

Ding

et al. 2018

International Journal of Agricultural and Biological Engineering

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“…Among the models, FL was the best one, which gave a good fit on WASDs with the normal or log-normal statistical pattern, whereas the FR model yielded the largest R 2 values only when the aggregates sizes were normally distributed. There are several reports that the WASD follows a power function (Baldock and Kay 1987;Caruso et al 2011). In this case, the exponent of the function can be a descriptor of soil structure status.…”

Section: Coefficient Of Determination (Rmentioning

confidence: 99%

Evaluation of models for description of wet aggregate size distribution from soils of different land uses

Tirgarsoltani

Gorji

Mohammadi

et al. 2014

Soil Science and Plant Nutrition

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A proper description of aggregate size distribution (ASD) with an optimum mathematical model would be useful in modeling and monitoring land use effect. The objective of this study was to evaluate the suitability of six cumulative distribution models, namely, Jaky, normal, log-normal, Rosin-Rammler, Fredlund and a mass-based fractal model with wet aggregate size distribution (WASD) data sets from a given range of soil structural properties. The models were tested on wet sieving data of samples that had been collected from a number of different land use types (dry farmland, rangeland and forestland). Three statistical criteria, namely, coefficient of determination (R 2 ), Mallows statistics (C p ), and Akaike's information criterion (AIC), were used for evaluating model performance, based on the least sum of square error and number of fitting parameters. Analysis of R 2 showed that the Fredlund three-parameter model showed the best performance in all of the soils apart from the number of parameters. The log-normal model gave a good fit on WASD from rangeland and forestland; it was the best especially in dry farmland. The normal model provided a good description of WASD from the rangeland and forest. However, it failed in dry farmland. According to C p and AIC as the evaluation criteria, the fractal model was the optimum to describe WASD for all of the land uses. The Fredlund, log-normal, Jaky and Rosin-Rammler models ranked next in the given order.

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“…Assim, Collembola é um grupo de microartrópodes pertencentes a mesofauna e amplamente distribuídos no solo (GANGE; BOWER, 1997) e são excelentes representantes da diversidade da fauna do solo (CASSAGNE et al, 2003). Estes microartrópodes do solo têm influência significativa na ecologia microbiana do solo, ciclagem de nutrientes e fertilidade do solo, alimentando-se de microrganismos do solo e matéria orgânica morta.…”

Section: Introductionunclassified

Por que devemos nos importar com os colêmbolos edáficos?

Filho

Baretta

2016

RSA

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Este trabalho de revisão tem como objetivo apresentar a importância dos colêmbolos edáficos, com destaque para aspectos agronômicos e ecológicos. São abordadas as características gerais, densidade e distribuição dos colêmbolos, bem como a relação dos colêmbolos com práticas agrícolas, com fungos, com ciclagem de nutrientes e fertilidade do solo. São também reportados trabalhos da literatura, demonstrando a importância desses organismos aos serviços do ecossistema, como ciclagem de nutrientes, melhoria na fertilidade, agregação do solo, controle de fungos e indicadores da qualidade do solo. Pretende-se com este trabalho demonstrar o importante papel desempenhado pelos colêmbolos e expandir o campo de pesquisa com esses organismos, aumentando o conhecimento dos importantes processos mediados por eles e a interface entre a Ecologia do Solo e Ciência do Solo.

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Are power laws that estimate fractal dimension a good descriptor of soil structure and its link to soil biological properties?

Cited by 25 publications

References 45 publications

Field experimental study on optimal design of the rotary strip-till tools applied in rice-wheat rotation cropping system

Field experimental study on optimal design of the rotary strip-till tools applied in rice-wheat rotation cropping system

Evaluation of models for description of wet aggregate size distribution from soils of different land uses

Por que devemos nos importar com os colêmbolos edáficos?

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