How Water Quality Affects Your Crop Production
You can have the perfect fertilizer program, ideal soil conditions, and optimal weather—but if your irrigation water is working against you, your crops will never reach their full potential. Water quality is one of the most overlooked factors in crop production, and it's something we test with our water testing service for every client at Agconnect.
Why Water Quality Matters
Every time you irrigate, you're not just adding water to your soil—you're adding everything that's dissolved in that water. Over a growing season, this can add up to significant amounts of minerals, salts, and other compounds that affect both your plants and your soil.
Consider this: If your irrigation water contains 200 ppm of sodium and you apply 3 acre-feet of water per season, you're adding over 1,600 pounds of sodium per acre annually. That sodium accumulates in your soil year after year.
Key Water Quality Factors
pH Levels
Water pH directly affects nutrient availability. When water pH is too high (alkaline), several things happen:
- Nutrient lockout: Iron, manganese, zinc, and other micronutrients become less available
- Fertilizer inefficiency: Some fertilizers are less effective in high pH water
- Scale buildup: Calcium and magnesium can precipitate out, clogging drip systems
Most plants prefer water in the 5.5-6.5 pH range for optimal nutrient uptake. If your water is significantly higher, you may need to acidify it or use products designed to work in alkaline conditions.
Bicarbonates
High bicarbonate levels are extremely common in California groundwater and can cause serious problems:
- Raise soil pH over time
- Bind with calcium and magnesium, making them unavailable
- Create surface crusting and poor water infiltration
- Reduce the effectiveness of fertilizer applications
Our Borreplex OA is specifically formulated to acidify irrigation water, reduce bicarbonates, and improve water penetration into the soil.
Sodium and Chloride
Elevated sodium levels are particularly damaging because sodium:
- Destroys soil structure by dispersing clay particles
- Competes with beneficial cations like calcium and potassium
- Creates saline conditions that stress plants
- Is difficult to remove once it accumulates
Chloride, while less destructive to soil structure, can accumulate to toxic levels in plant tissue, causing leaf burn and reduced yields.
Electrical Conductivity (EC)
EC measures the total dissolved salts in your water. High EC water:
- Adds to soil salinity with every irrigation
- Increases plant water stress
- Reduces nutrient uptake efficiency
- Can cause salt accumulation in the root zone
Specific Minerals
Beyond general salinity, specific mineral content matters:
- Calcium and Magnesium: Generally beneficial, but can cause scale issues
- Boron: Essential in small amounts, toxic at higher levels
- Iron: Can cause staining and may indicate other problems
- Sulfur: Usually beneficial, but high levels can cause issues
How Poor Water Quality Affects Your Fertility Program
Nutrient Lockout
When water pH is high or certain minerals are present, your fertilizer may not work as expected. We often see growers applying iron fertilizers with no response—because the high pH of their irrigation water immediately converts the iron to unavailable forms.
Signs of nutrient lockout:
- Chlorosis (yellowing) despite adequate fertilization
- Deficiency symptoms that don't respond to applications
- Inconsistent plant response across the field
- Higher fertilizer costs without better results
Soil Structure Degradation
High sodium water gradually destroys soil structure. As clay particles disperse:
- Water infiltration decreases
- Compaction increases
- Root penetration is limited
- Aeration decreases
- Beneficial microbe populations decline
This is often a slow process that goes unnoticed until the damage is severe.
Accumulation Problems
Minerals don't just disappear—they accumulate in your soil year after year. Without proper management:
- Salinity builds up in the root zone
- pH gradually shifts
- Nutrient imbalances develop
- Soil productivity declines
Testing and Managing Water Quality
What We Test For
Our water quality analysis service includes:
- pH and EC
- Bicarbonates and carbonates
- Sodium, calcium, and magnesium
- Chloride and sulfate
- Boron and other trace elements
- SAR (Sodium Adsorption Ratio)
Management Strategies
Once we understand your water quality, we can recommend appropriate management strategies:
For High pH/Bicarbonates:
- Acidification with Borreplex OA or other organic acids
- Fertilizer selection (using acidifying forms)
- Timing applications to minimize exposure
For High Sodium:
- Gypsum applications to displace sodium
- Improved drainage to leach salts
- Calcium-based amendments
For High Salinity:
- Leaching irrigations
- Salt-tolerant variety selection
- Modified irrigation scheduling
For Mineral Imbalances:
- Targeted fertilizer programs
- Soil amendments to adjust ratios
- Foliar applications to bypass soil issues
Case Study: Transforming Problem Water
One of our clients in the Paso Robles area had struggled with declining yields for years. Their fertility program looked good on paper, but plants weren't responding.
Water test results showed:
- pH of 7.8 (too high for optimal nutrient uptake)
- Bicarbonates at 380 ppm (extremely high)
- Sodium at 165 ppm (causing structure problems)
Our solution:
- Acidified irrigation water with Borreplex OA
- Applied gypsum to address sodium
- Adjusted fertilizer forms for alkaline conditions
- Modified irrigation timing and amounts
Results after one season:
- 22% yield increase
- Improved fruit quality
- Better water infiltration (reduced irrigation needs by 15%)
- Lower overall fertilizer costs
Getting Your Water Tested
Don't guess about your water quality—test it. Even if you've tested before, conditions can change:
- New wells may access different aquifers
- Drought conditions concentrate minerals
- Seasonal variations affect quality
- Municipal water sources may change
We recommend testing:
- Annually at minimum
- After any change in water source
- If you notice unexplained plant problems
- At the beginning of a new project
Take Action Now
Water quality issues are often fixable, but the longer they go unaddressed, the more damage accumulates in your soil. If you haven't tested your irrigation water recently, now is the time. Water testing is a key component of our five-element approach to fertility management.
For a broader understanding of how water quality fits into overall crop health, see our article on understanding soil health.
Contact Agconnect to schedule a comprehensive water quality analysis. We'll help you understand your results and develop a management plan that protects your soil and maximizes your crop production.
Call 805-467-2233 or email [email protected] to get started.
Agconnect, Inc. has been helping growers optimize their water and fertility management since 1999. Our products, including Borreplex OA, are specifically designed to address the water quality challenges common in California and Mexico agriculture.