Soil crumbs

Emerson, W. W. 1964. The slaking of soil crumbs as influenced by clay mineral composition. Aust. J. Soil Res. 2 211-217. 

Fig.16.2. Possible arrangements of domains (packs), organic matter, and quartz in a soil crumb.

Soil crumbs owe their stability in part to the presence of naturally occurring polymeric materials (humus), which bind to the soil. The first synthetic polymers to improve soil structure and enhance crop growth were introduced in 1951. The results of incorporating polymers into soil were spectacular, but the dose rates required made their use uneconomical. 

The polymers are effective through two mechanisms, soil binding and flocculation. The polymer can bind to soil crumbs, giving structural stability. This reduces crumb breakdown on irrigation and maintains an open structure, which facilitates infiltration. This mechanism... 

Studies have shown that high molecular weight anionic polyacrylamide polymers are most effective as soil stabUisers [76]. These polymers bind primarily to calcium ions that are in themselves bound to anionic sites on the surface of the soil crumb (a process known as calcium bridging or salt linkage). The anionic nature of the soil crumb arises due to the anionic surface charge of the clay portion within the sod. 

In the agriculture area, VAMA resins are useful for fertilizer coatings and binders and soil modifiers.The resin stabilizes soil crumb and acts as a soil structure builder to prevent soil erosion.Crop soils treated with VAMA resins and salt derivatives of the resin have improved quality and as a result of improved bacteria growth and nutrient utilization produce greater yields of various grains. 

CLAPP C.E. and EMERSON W.W. 1965. The effect of periodate oxidation on the strength of soil crumbs I Qualitative studies. Soil Science Society of America Proceedings, 29, 127-130. 

CURRIE J.A. 1966. The volume and porosity of soil crumbs. Journal of Soil Science, 17, 24-35. 

Long-term grasslands provide plenty of organic matter for humus formation. If the soil is not acidic or waterlogged, the soil fauna and flora create humus and the subsequent useful development of a porous crumb and granular structure. Porosity encourages root growth and the uptake of soil nutrients. 

Sliding of crumb surface soil into cracks and the resultant shearing have important consequences ... 

Small tire chips have also been utilized as a soil amendment to improve athletic playing fields (see Recreational surfaces). A patented process marketed under the trade name Rebound (Jai Tire) combines crumb mbber from scrap tires with composted oiganic material to reduce soil compaction, resulting in better athletic playing surfaces (52). Installations have been made in Florida, California, Colorado, Hawaii, Maryland, Michigan, Missouri, Nevada, Virginia, and Wisconsin. 

The use of vinyl eraser crumbs may be viable for the removal of some surface soils. However, the amount of pressure used and the direction the eraser crumbs are rolled are critical. Moving across or against the "grain" of the tapa will cause bits of fiber to be picked up on the eraser crumbs. 

The solute increases to a concentration limited by its solubility, leading for example to the efflorescence of salt crystals seen on the surface of crumbs on a fertile soil after drying. 

Assessment of the soil in terms of these criteria gives a very accurate picture of the state of the soil. In particular, the distribution of the crumb structure, roots and moisture very soon reveals where horizons that impede plant growth are present in the soil. 

In crumbly soil there is abundant, uniform and deep root penetration the individual roots are extended (crumb <10 mm). 

How to Use A low container, such as a tuna can or pie plate, set into the soil so the rim is even with the soil surface and baited with fish oil or oil-soaked bread crumbs will attract large numbers of earwigs. 

Russell, E.W. (1938), Measurement of Pore-space and Crumb or Aggregate Structure of Soils. Proc. Third Conf. Cotton Growers-problems, Rothamsted Exp. Stn. 

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