Monitoring Tools

Electrical Conductivity

  • E.C. “Electrical Conductivity” is the movement of nutrients in the soil solution. Ideal E.C. levels are between 400-800 mS. Below 400 mS the nutrients do not move through the soil very well essentially starving the plant. Resulting in the plants looking unhealthy and weak. Above 800 mS too many nutrients are moving through the plant at the same time causing the plant to be overwhelmed. When overwhelmed the plant may experience tip burn, root burn, and limited productivity. Between the ideal levels nutrients will be able to move through the soil to the plant easily helping to produce a healthy and strong plant.
  • EC is measured in ERGS = Energy Release per Grams per Second
  • Conductivity levels strongly correlate with salinity. The salinity of the soil solution, irrigation water or fertilizer solutions can all have an effect on the root zone environment as well as the electrical conductivity levels.

Refractometer

Brix is a measurement of the sugar level in plant extracts as created through photosynthesis. Brix is measured with an instrument called a Refractometer. Ideally, Brix readings should be taken on a sunny day between the hours of 11:00am and 4:00 pm when sugar content is highest. However, it is more important to consistently take Brix readings at about the same time so that you have an accurate comparison throughout the growing season. Carbon along with a vast array of trace elements have significant impacts on Brix readings. If you are seeing low Brix readings, there may be insufficient carbon and trace element levels to sustain an elevated Brix reading. The Brix levels in a plant are relative to the plants health. The lower the Brix, the sicker the plant; and the higher the Brix the healthier the plant looks.

The following chart is a quick reference to the benefits of higher brix readings in various crops:

Brix Reading Plant condition and resistance
0-6 Molds, Algae and Fungus fail to thrive on the plant
10 and higher Plants compete with weeds and are able to draw minerals from air
14 and higher Insects can no longer tolerate the sap due to high sugar content.

Crop Poor Average Good Excellent
Alfalfa 4 8 16 22
Apples 6 10 14 18
Asparagus 2 4 6 8
Avocados 4 6 8 10
Bananas 8 10 12 14
Beets 6 8 10 12
Bell Peppers 4 6 8 12
Broccoli 6 8 10 12
Cabbage 6 8 10 12
Carrots 4 6 12 18
Cantaloupe 8 12 14 16
Casaba 8 10 12 14
Cauliflower 4 6 8 10
Celery 4 6 10 12
Cherries 6 8 14 16
Coconut 8 10 12 14
Corn Stalks 4 8 14 20
Corn, Young 6 10 18 24
Cow Peas 4 6 10 12
Cumquat 4 6 8 10
Endive 4 6 8 10
English Peas 8 10 12 14
Escarole 4 6 8 10
Field Peas 4 6 10 12
Grains 6 10 14 18
Grapes 8 12 16 20
Grapefruit 6 10 14 18
Green Beans 4 6 8 10
Honeydew 8 10 12 14
Hot Peppers 4 6 8 10
Kohlrabi 6 8 10 12
Lemons 4 6 8 12
Lettuce 4 6 8 10
Limes 4 6 10 12
Mangoes 4 6 10 14
Onions 4 6 8 10
Oranges 6 10 16 20
Papayas 6 10 18 22
Parsley 4 6 8 10
Peaches 6 10 14 18
Peanuts 4 6 8 10
Pears 6 10 12 14
Pineapple 12 14 20 22
Raisins 60 70 75 80
Raspberries 6 8 12 14
Romaine 4 6 8 10
Rutabagas 4 6 10 12
Sorghum 6 10 22 30
Squash 6 8 12 14
Strawberries 6 10 14 16
Sweet Corn 6 10 18 24
Sweet Potatoes 6 8 10 14
Tomatoes 4 6 8 12
Turnips 4 6 8 10
Watermelon 8 12 14 16

Monitoring Aerobic or Root Zone

The aerobic zone is the area in which a plant is able to uptake nutrients. An increase in the aerobic zone will allow the roots of a plant to have access to a larger area of nutrients. You can measure the aerobic zone by pushing a soil compaction tester (depicted below) into the soil until it reaches 300 psi; this marks the depth of the aerobic zone. The feeder roots are not able to grow past 300 psi. The goal is to get the aerobic zone as deep as possible. A larger aerobic zone allows for the following:

  • Quicker seed emergence
  • Air to get to the roots
  • Improved root growth (by breaking up compaction)
  • Increase in uniformity throughout the stands
  • Increased microbial activity, essential for healthy soils