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LSP Report LS7019

The Effects of Soil Compaction on the Production of Processing Vegetables and Other Cash Crops:
A Review



Researcher: C.K. Stevenson, RCAT, Principal Researcher; G.S. Iler  

Funding: $15,000

Objectives

  1. To conduct a literature review on the effect of soil compaction on the production of processing vegetables (i.e., tomatoes, sweet corn, green peas and green and wax beans) and other cash crops and to survey the state of the art for the prevention and relief of this problem.
  2. The summary of research findings would help to illustrate the significance of and improve the awareness of soil compaction among growers.
  3. The literature review could act as a stepping stone to applied research on soil compaction.

Expected Benefits

  1. To create a current state of the art knowledge base. From this base future research strategies could be better targeted to modify current production practices.
  2. Information gathered can be used to emphasize the importance to extension workers and farmers, of the serious effects that soil compaction has on the soil when intensive cash cropping occurs.

Summary of Research Results

In recent years, increased mechanization and rationalization has increased the risk of soil compaction in Ontario's processing crop industry. Reports from the field are confirming the compaction damage from increased field traffic.

Soil compaction is a reorganization of soil particles resulting from external compression forces on the soil. Compaction increases the bulk density of soil due to a decrease in the number and volume of large pores, which in turn alters aeration, water infiltration, and hydraulic conductivity, and increase soil strength.

Soil compactibility is dependent on soil texture, with well graded soils compacting more tightly than poorly graded soils.

Soil compaction will increase with increases in soil water content, tire contact pressure, and vehicle weight, or axle load. Compaction will decrease with increased vehicle speed, reduced or controlled traffic, and increased number of wheels carrying the vehicle. The use of tracks to replace tires may reduce soil compaction. At great depth, the stress caused by traffic mainly depends on the axle load. Present data show axle loads above 10 tonnes per axle should never be used otherwise soil may be damaged permanently.

Lightly or moderately compacted soil may not cause reduced yields and may improve yields, especially in dry soil conditions. Yield increases in dry years result from improved soil water and nutrient transport.

Severely compacted soil impedes root growth and development. This restricts a plant's ability to utilize soil water and nutrients by reducing the soil volume utilized by roots. In very wet or very dry soil, compaction multiplies the impact of stress on the plant and reduces plant yield. However, if adequate moisture and nutrients are supplied to the reduced root system, the effect of compaction will be negligible.

Soil compaction can affect nutrient availability. It can increase incidence of soil borne plant diseases and reduce the beneficial microbial population.

There has been relatively little research done on the effect of soil compaction on the yield of processing vegetable crops. Compaction can reduce yield by reducing the quality, weight and size of the fruit. It can delay plant development and maturity, reduce plant stand, height and seedling emergence. Subsoil compaction can reduce yields by delaying planting and other field operations.

The reduction in crop yield and quality due to soil compaction is an economic cost to growers and processors. Compaction also increases input costs.

The alleviation of compacted conditions can result from freezing/thawing and wetting/drying cycles but this effect is limited to the upper layers of soil, especially in the short term. Research has shown that the effects of subsoil compaction persist for some time even in years with heavy frost. The alleviation of subsoil compaction may result from the growth of plant roots or the action of earthworms.

Subsoiling, as examined by research, has shown mixed results, with in-row subsoiling showing the greatest benefits. The placement of fertilizer to compensate for compaction-reduced yield reductions has benefits and is receiving attention.

Further research is needed to better understand the nature of soil under compression, the mechanics of plant growth under compacted soil conditions, and the process of compaction alleviation. To reduce the risk of soil compaction new machinery and crop production systems need to be developed.

 

 

 

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Created: 03-23-1996
Last Revised: Tuesday, May 10, 2011 12:45:55 PM