Step 6: Diagnosis

  1. Patterns suggest problems are related to management practices (irrigation and herbicide application).
  2. Shorter plants in the middle rows (2 and 3) is due to saline soil.
    • Why? Past rill irrigation in hops resulted in the lateral movement of salts to what are now, the middle rows.  Excess moisture along drip lines brought salts to the upper soil horizon increasing soil salinity.  High saline soils are known to delay plant development and cause stunting.
  3. Chlorosis concentrated in outer rows (1 and 4) is due to Nitrogen deficiency
    • Why? Rows 1 and 4 were planted along old furrows.  Years of broadcast fertilizer applications in furrows resulted in lateral and vertical (leaching) movement of N.  Therefore, N concentrations are severely reduced in outer rows.  Furthermore, fertilizers (currently applied through the drip system) may not be moving far enough from the drip line in the soil solution to supply adequate amounts of N to plants in the outer rows.
  4. Purpling along the margins of some plants in middle rows (2 and 3) is due to Phosphorus deficiency.
    • Why? High salinity in middle rows stunted plants and reduced root proliferation.  With less root proliferation, there is less P up-take.  Furthermore, P availability is reduced in cool, alkaline soils.
  5. Chlorosis and purpling of midrib in some plants throughout the field looks like ALS herbicide injury, which is exaggerated at high soil pH.