Thursday, April 19, 2012

Posts from the Archive: The Goal and Objectives of Good Irrigation Management.


Sometimes you stumble on some old work and say,  wow did I write that?   Below are some thoughts on the benefits of good irrigation scheduling.


Perhaps the most misunderstood, over looked, and under utilized practice in crop production systems today is proper irrigation scheduling; it encompasses the most critical input, water. Water is the catalyst for many phyto-chemical reactions within the plant that are necessary for the plant to obtain optimal health.  Below is the rational and legitimacy of irrigation scheduling.

GOAL:
Irrigation scheduling should be utilized as a mechanism to respect the water consumption needs of plants through their various growth and developmental stages in order to attain high yields while maintaining soil quality and conservation of water.

OBJECTIVES:

1.  Target soil moisture depletion percentages should be utilized by to schedule the irrigation of fields.

2.  The “feel” method and other technologies should be used to properly monitor soil depletion levels.

3.  The calculation of moisture loss should be equated by utilizing evapo-transpiration in accordance with the modified penman equation and crop coefficients.

4.  Improve uniformity of irrigation applications by calculating flow rates and application efficiencies of the irrigation system being utilized.

5.   Influences such as moisture holding capacity, knowledge of the plant root depth, soil texture, salinity, and organic matter should be considered when determining plant available water.

6.  Improve soil absorption and pecolation efficiencies in order to properly leach accumulated salts through, and past, the root-zone profile by properly quantifying the target moisture level in the root profile and the amount of water to be applied.

7.  Critical growth stages should be considered and irrigation should be utilized to improve crop quality.

8.  Mitigation of ground water pollution from fertilizers by increasing plant root depth and allowing proper moisture transport through the soil profile and optimizing nutrient management.

Proper irrigation scheduling is vital in order to optimize plant and soil interactions.  Water plays important roles in many facets of not only plant health, but also in soil fertility.  That being the case, quantifying the amount of water and the time between irrigations has a direct affect in the quality of a crop.

Monday, March 5, 2012

Alfalfa Irrigation, the last kiss before the cutting.

Good alfalfa production depends on good irrigation scheduling in the desert.   The most critical irrigation is the one prior to the cutting.  Fields that lack sufficient water for good regrowth after the cutting suffer significant yield losses.    Each day a cutting is delayed after an irrigation is worth 4 days in the windrow for curing (1.4 Kc vs 0.3 Kc).    Below is a table to assist local growers in estimating the minimum time needed for the soil to be sufficiently dry to swath the field.