Journal ArticleDOI
Seedling emergence as influenced by aggregate size, bulk density, and penetration resistance of the seedbed
Hoda M. Nasr,F. Selles +1 more
TLDR
In this article, the impact of bulk density and aggregate size distribution of the seedbed on the emergence of Hard Red Spring Wheat (Triticum aestivum L.v.Abstract:
Producers in western Canada are concerned with producing good seedbeds in conservation tillage systems. A thorough understanding of how seedlings interact with the soil surrounding them is required to develop criteria for designing effective furrow openers and packing devices suitable for use in conservation tillage systems. To facilitate interpretation of field evaluations of furrow openers for zero tillage seeders, we conducted a greenhouse experiment designed to assess the impact of bulk density and aggregate size distribution of the seedbed on the emergence of Hard Red Spring Wheat (Triticum aestivum L.). Seeds of wheat (c.v. Lancer) were germinated in seedbeds with five aggregate size distributions with geometric mean diameter ranging from 0.44–12.67 mm, and four bulk densities ranging from 1.0–1.6 Mg m−3 arranged in a factorial design. The soil used in this study was taken from the Ap horizon of a Swinton silt loam (Orthic Brown Chernozemic). A logistic model including bulk density, geometric mean diameter and time since initiation of the experiment explained 90% of the variation observed during the course of emergence, and a logistic model that used penetration resistance and time explained 86% of this variability. Number of seedlings emerged and speed of emergence were affected by bulk density and aggregate size of the seedbed, and by the interaction of both variables. In general, increasing bulk density or aggregate size delayed emergence and reduced total emergence. However, the effect of bulk density was small in seedbeds with large aggregates, and the effect of aggregate size was negligible in compacted seedbeds. Increased bulk density delayed emergence mainly by decreasing the volume of voids in the soil. This elevated the interfacial stress to the elongating coleoptile. The detrimental effect of increased aggregate size was mainly due to increase in the length of the path the coleoptile had to traverse to reach the soil surface, as it elongated through the interaggregate voids. Compaction of the seedbed, necessary to achieve the higher bulk densities in the coarser-aggregate seedbeds, resulted in substantial breakdown of larger aggregates. Consequently, as the interfacial stress was increased by compaction, the path length was decreased, and both effects cancelled each other.read more
Citations
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Journal ArticleDOI
Long-term effects of tillage systems and rotations on soil structural stability and organic carbon stratification in semiarid central Spain
TL;DR: In this paper, the long-term effects of tillage systems on water stability of pre-wetted and air dried aggregates, soil organic carbon (SOC) stratification and crop production were studied in a Vertic Luvisol with a loam texture.
Journal ArticleDOI
Disruptive methods for assessing soil structure
TL;DR: In this paper, the authors present and discuss methods and indices used to characterize soil structure based on the size distribution and stability of fragments produced by breaking apart the soil matrix The size of fragments is inversely related to the mechanical stress applied Thus, the selection of an appropriate fragmentation procedure is critical if information on soil structure is to be recovered.
Journal ArticleDOI
Comparing hemp (Cannabis sativa L.) cultivars for dual-purpose production under contrasting environments
Kailei Tang,Kailei Tang,Paul C. Struik,Xinyou Yin,C. Thouminot,Marie Bjelková,V. Stramkale,Stefano Amaducci +7 more
TL;DR: Both Fedora 17 and Futura 75 are candidate cultivars for dual-purpose production in Italy, France and the Czech Republic, with Fedora 17 being more suitable for seed production and FutURA 75 for fibre production.
Journal ArticleDOI
Soil Structural Disturbance Effects on Crop Yields and Soil Properties in a No-Till Production System
TL;DR: In this article, the effects of periodic tillage disruption in continuous no-till (NT) systems on soil properties and the yields of winter wheat (Triticum aestivum L), double-cropped soybean [Glycine max (L.) Merr], and maize (Zea mays L.) in rotation were characterized.
Journal ArticleDOI
Mechanical and cropping behavior of direct drilled soil under different traffic intensities: effect on soybean (Glycine max L.) yields
TL;DR: In this article, the effect of different traffic intensities on soil physical properties and soybean ( Glycine max L.) yields under a direct drill system were compared in the western part of the Rolling Pampas Region.
References
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Book ChapterDOI
Aggregate Stability and Size Distribution
W. D. Kemper,R. C. Rosenau +1 more
TL;DR: An aggregate is a group of primary particles that cohere to each other more strongly than to other surrounding soil particles as mentioned in this paper, and disintegration of the soil mass into aggregates requires imposition of a disrupting force.
Journal ArticleDOI
Advances in characterization of soil structure
TL;DR: Soil structure is defined as "the spatial heterogeneity of the different components or properties of soil" as discussed by the authors, and it is a property of soil that is important for plant development, soil water balance and soil workability.
Book
An Introduction to Crop Physiology
F. L. Milthorpe,Jeffrey Moorby +1 more
Abstract: Prefaces Acknowledgements 1. Prolegomena 2. The environment 3. The supply and use of water 4. The absorption and transport of mineral nutrients 5. Photosynthesis and respiration 6, Germination and seeding emergence 7. vegetative growth 8. Flowering and fruit growth 9. Some aspects of overall growth and its modification 10. The prediction of responses Glossary Appendices Index.