Fruit tree water requirements
Soil type will help you estimate water holding capacity (inches of water available to plants). Soil texture influences the water holding capacity of soils. The proportion and absolute amount of water available to the plant in coarse-textured, sandy soils is less than in fine-textured, clay soils, therefore clay holds the most water.
Each foot of soil depth holds:
|Sands||1.0–1.5 inches of water|
|Loam||1.5–2.0 inches of water|
|Clays||2.0–2.5 inches of water|
Citrus Growth Stages
• Flowering, Fruit Set and New Flush Development:
This growth stage must have optimum soil moisture. Even a slight water deficiency means that leaves are smaller, and the plant is not in its prime. Severe water deficiency results in poor leaf development, incomplete flowering, poor fruit set and a high rate of fruit drop (Food and Fertilizer Technology Center, 2003). The soil water tension reading should be 30 – 60 cBar.
• Fruit Development:
The remaining fruits now begin to develop, and it is during the late fruit development stage that citrus trees need their greatest amount of water because of the high transpiration rate. Not having enough water at this stage would inhibit photosynthesis. The water tension reading at this time should be between 60 and 90 cBar.
• Fruit Maturing Stage:
At this stage of fruit development the quality of the fruit is the concern. A high soil moisture content promotes vegetative growth which does not help the already existing fruit. In order to slow vegetative growth and improve reproductive growth, soil should be kept fairly dry, without any irrigation, roughly 80 to 95 cBar.
• After Harvest:
After the fruit is harvested, the tree requires a small amount of irrigation water; just enough to meet ET requirements, to restore tree growth back to its normal rate. A minimal amount of irrigation water will maintain photosynthesis in the leaves and help to avoid nutrient stress.
On a scale of 0 to 100 cb soil watertension, how wet is your field?
Our research has allowed us to determine the threshold SWT of various crops growing on silt loam under different irrigation systems. We found that irrigating at these critical values has significant benefits to crops.
Roughly speaking, a GMS reads the following scale of SWT for a medium-texture soil:
The SWT irrigation threshold varies not only by crop but also by soil texture, climatic factors, and irrigation method. The threshold values that maximize marketable yield are known for a wide array of commercial crops growing on different soils under different climatic conditions and irrigation systems (Tables 1–4, pages 7–9).
• > 80 cb indicates dryness.
• 20 to 60 cb is the average field SWT prior to irrigation, varying with the crop, soil texture, weather pattern, and irrigation system.
• 10 to 20 cb indicates that the soil is near field capacity.
• 0 to 10 cb indicates that the soil is saturated with water.