Soil Conservation

Soil Conservation in Dole’s Agricultural Practices

In order to offer consumers fruits and vegetables of the highest quality, Dole makes it a priority to maintain healthy soil in its farms. In fact, soil conservation is one of the “Four Pillars of Sustainability” that Dole emphasizes in business.

Dole’s soil conservation programs focus on:

  • Preventing soil erosion
  • Avoiding soil overuse and chemical alterations
  • Ensuring a healthy and productive soil
  • Reducing the depletion of soil nutrients
  • Contributing to improved water availability

Before preparing soil for use, a soil management plan must be developed. Soil management at Dole includes extensive fertility analyses, landscape assessments, determination of soil classes for the specific crop and contour technique appraisal.

By taking these steps, the Company maximizes the soil’s productivity and minimizes erosion through identifying soil conservation alternatives before each farm area is planted.
Depending on the crops and production areas, specific programs implemented to protect soils include:

    • Minimum tillage
    • Crop rotation
    • Cover crops
    • Mulch with plastic or pasture
    • Ditch stabilization
    • Mechanical barriers
    • Soil maps
    • Top-soil thickness analyses
    • Organic amendments

Minimum Tillage

This practice reduces the manipulation of soil by limiting turn-overs and structure breakdowns. Minimum tillage also limits working the soil with machinery, thus reducing erosion and soil compaction and increasing water intake. Another way that Dole reduces tilling and enhances soil health is through the use of “ratoon crops” in the pineapple production system. Ratoon crops are plants that provide a second harvest and develop up from the roots of the previous crop.

Crop Rotation

This practice consists of planting a series of dissimilar crops in the same area in sequential periods. It hinders the spreading of pests and diseases by breaking their regular biological cycle, thus reducing the need for pest control products. In banana cultivation, for example, the use of crop rotation has allowed us to reduce nematode populations and eliminate the need to employ nematicides in several growing regions.

 

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Cover Crops

A cover crop is a plant that can be used to protect soil from erosion due to heavy rainfall and slopes in the terrain, control weeds and manage soil fertility. For example, soy and mucuna can enhance soil fertility by fixing nitrogen into the earth. Additionally, they can later be incorporated into the field (prior to planting the fruit crop) as a way to reduce the depletion of soil nutrients and the use of fertilizers. Cover crops can be grown as a monoculture or in combination with commercial crops, such as within the banana plantations.

Cover crops and crop rotation are usually used together, in order to optimize benefits.

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Additional Programs

Mulch with Plastic or Pasture
Using mulch with plastic or pasture between planting beds reduces erosion and the presence of pests and weeds. In turn, mulch contributes to a decreased need for pesticides.

Ditch Stabilization
Erosion can be greatly reduced by implementing practices that stabilizing drainage ditches. Through the years, Dole has found that using cover plants in the canals are the most effective way to reduce erosion, as well as protect or enhance the quality of the water draining from the farm.

Mechanical Barriers
Mechanical barriers are physical obstacles that can be installed into a farm’s drainage system to decrease erosion. Bamboo stakes make for efficient mechanical barriers due to their ability to capture soil and reduce the speed of water running through ditches.

Soil Maps
Maps of the land’s soil are created to help identify which areas are particularly vulnerable to erosion and assist in determining the planting structure for the farm. Knowing this information enables the Company to take appropriate preventative measures and issue soil conservation recommendations based on this data.

Soil conservation practices at Dole include: contour cultivation and planting, broad-base preservation terraces, tailored tilling according to the soil’s characteristics, soil morphological analysis, detailed physical and chemical evaluations and lastly, returning soil trapped in barriers back into the fields.

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Organic Amendments

An organic amendment is any material of plant or animal origin that can be added to the soil to improve its physical properties, including water retention, permeability, water infiltration, drainage, aeration and structure.

Dole uses organic amendments, such as compost and humic acids, to preserve top-soil and increase organic matter in the field. A greater amount of organic matter improves the soil structure, facilitates water and nutrient absorption, decreases erosion and overall enhances plant development.

Another way to preserve soils and increase organic matter content is to incorporate more plant material (crop residue) after harvesting the crops.  Traditionally, pineapple plant residue was desiccated using an herbicide and then burned. For environmental purposes, this method has been replaced by manual and mechanical methods that incorporate the crop residue into the soil, thus increasing organic matter and soil carbon.

Not only do these programs limit soil erosion, but they also reduce the use of herbicides, fertilizers and other agrochemicals, while protecting valuable natural resources and groundwater.

Dole seeks technologies to improve its productivity and sustainability.  In doing so, it has become one of the few companies to measure soil erosion levels in the fields.  All findings are included in a farm-specific soil conservation manual that Dole developed and continues to update every three years.