Irrigation & Soil Health Best Management Practices

The State of Kansas works continuously with local, state and federal stakeholders to provide incentives to reduce the depletion of groundwater in areas of significant decline. Water conservation practices offered by the State of Kansas are designed to reduce depletion of groundwater sources in targeted areas. In addition, the State provides financial assistance to landowners to permanently retire their water rights in selected areas as determined by the State.

Water Conservation Programs for Retiring Water Rights
Irrigation Water Management is used to accomplish one or more of the following purposes:

• Manage soil moisture to promote desired crop response.
• Optimize use of available water supplies.
• Minimize irrigation-induced soil erosion.
• Decrease non-point source pollution of surface and groundwater resources.
• Manage salts in the crop root zone.
• Manage air, soil, or plant micro-climate.
• Proper and safe chemigation or fertigation.
• Improve air quality by managing soil moisture to reduce particulate matter movement.
• Reduce energy use.

🧩 Combining Soil Health & Irrigation for Maximum Benefit
To get the most conservation benefit:

• Use no‑till to preserve soil structure and improve infiltration.
• Add cover crops to increase soil organic matter and water holding capacity.
• Use drip/smart irrigation to match water use to soil needs.
• Rotate crops and maintain biodiversity for strong soil biology.
• Regularly test and monitor soil health metrics.
• Review local standards via NRCS Field Office Technical Guides for Kansas‑specific criteria.

Best Soil Health Conservation Practices
1. Minimize Soil Disturbance
Reducing tillage lowers erosion, protects soil structure, improves water infiltration, and reduces fuel and labor costs.
2. Keep Soil Covered Year‑Round
Use cover crops, plant residues, or mulches to prevent erosion and enhance moisture retention and organic matter.
3. Maximize Biodiversity
Crop rotations, diverse cover crop mixes, and integrated livestock help break disease cycles, support soil biology, and improve nutrient cycling.
4. Maintain Living Roots as Much as Possible
Living roots feed beneficial soil organisms, improve aggregation, and enhance water infiltration.
5. Adopt No‑Till or Reduced‑Till Systems
No‑till reduces erosion and conserves moisture while lowering annual input costs.
6. Implement Conservation Crop Rotations
Rotations break pest cycles, reduce chemical inputs, and improve soil biological health.
7. Use NRCS Conservation Practices Where Applicable
Some of the most soil-health–beneficial practices include:

• Cover crops (340)
• Contour farming (330)
• Contour buffer strips (332)
• Critical area planting (342)
• Conservation cover (327)

8. Regular Soil Health Measurement & Monitoring
The Soil Health Institute emphasizes standardized monitoring to ensure regenerative practices improve profitability, resilience, and sustainability.

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Soil Testing & Nutrient Management
Minimum Recommended Soil Test Levels

• N (Nitrogen): Depends on crop yield goal
• P (Phosphorus): 20 ppm
• K (Potassium): 130 ppm
• Zn (Zinc): 0.5–1.0 ppm
• S, Cl, B: Vary by crop
• pH:
  • Ideal: 6.8
  • Below 6.5 → nutrient availability issues begin
  • Below 6.0 → more severe problems

Fertilizer analysis example: 7‑21‑7 = percent of N‑P‑K by weight.
Key Principles of Nutrient Management
Nutrient management includes amount, source, form, placement, and timing.

• Improper placement/timing can negate benefits.
• Soil pH greatly affects nutrient interactions.
• Weather extremes (cold April soils, hot/dry July soils) intensify nutrient needs.
• When soil test levels are low, banding nutrients is more important.
• Rebuilding depleted soils requires substantial fertilizer:
  • +1 ppm P = 18 lb P₂O₅
  • +1 ppm K = 9 lb K₂O

Crop removal rates and site index should guide application rates.
Banding vs. Broadcast

• Banding nutrients near the seed acts like a “campfire”—roots grow toward the concentrated zone, especially in cool soil.
• Use broadcast/incorporation mainly for soil‑building, not immediate crop uptake.
• Fall applications reduce runoff risk.
• Corn needs more available P early due to cool spring soils.

Erosion, Nutrients, and Water Quality

• Eroded sites have lower nutrients and OM.
• Excess nutrients in water bodies often come from erosion, not direct application.

Nitrogen Management
Account for all nitrogen credits:
Previous legumes (soybean, alfalfa, clovers) Soil organic matter (20 lb N released per % OM per year) Animal manure Residue requires 4–8 weeks in warm, moist soil before N is released.
Soybean N credit should not be counted for wheat due to cool soil temperatures.
Corn nutrient timing:
By 12–18 inches tall, ear size is set—late N has limited yield impact.
Legume N Credits (approx.)

• Alfalfa:
  • 80% stand: 100–140 lb N
  • 60–80%: 60–100 lb
  • <60%: 0–60 lb
• Red clover: 40–80 lb
• Sweet clover: 100–120 lb
• Soybeans: ~1 lb N per bushel (30–60 lb typical)

Soil Sampling Best Practices
When sampling, consider:

• Slope
• Soil type
• Cropping history
• Manure‑applied areas
• Wet spots
• Odd/problem areas
• Gravel/limestone road influence (pH)

Sample Collection

• Sample at end of season before tillage.
• 15–20 cores (6" depth) per sample, up to 20 acres.
• A 160‑acre field needs at least 8 samples.
• Keep good records of sample locations.

GPS Grid Sampling

• Use ≤2.5‑acre grids for precise nutrient application.
• Use yield maps + soil tests to create variable‑rate prescriptions.
• Goal: manage each acre to its expected yield, not to uniformity.

Realistic yield goal:
5‑year average × 1.1

💧 Best Irrigation Conservation Practices
1. Use Efficient Irrigation Systems (Drip, Micro‑irrigation, High‑efficiency Sprinklers)
Drip irrigation reduces runoff, erosion, and soil salinity by applying precise water amounts at the root zone.
2. Implement Irrigation Scheduling Based on Soil Moisture
Use tools such as soil moisture sensors, ET data, and crop water use models to irrigate only when needed, preserving both water and soil structure.
3. Understand Soil Properties Before Irrigating
Texture, structure, and organic matter affect how quickly soils absorb and hold water. Clay holds more water but drains slowly; sand drains fast and requires more frequent irrigation.
4. Avoid Over‑Irrigation to Prevent Runoff and Erosion
Surface irrigation without proper design can cause erosion; efficient systems reduce those losses.
5. Integrate Irrigation with Other Conservation Practices
Using no‑till, cover crops, and contour systems improves water infiltration and reduces irrigation demand over time.
6. Adopt Smart Irrigation Technologies
Remote‑sensing tools, automated valves, and smart systems improve water‑use efficiency and are highlighted in sustainable irrigation research.
7. Select Crops and Varieties with High Water‑Use Efficiency
FAO‑supported recommendations emphasize choosing resilient, locally adapted crops to reduce irrigation burden.

📞 Call: (785) 266-9053 ext. 3                                                     Visit: 3231 SW VanBuren Street Ste: 2 Topeka, Kansas 66611                                        📧 Email: [email protected]