Page 23 - soil-plant-water relationship and water requirement

SOIL-PLANT-WATER RELATIONSHIP AND WATER REQUIREMENT

storm drains and streams. The infiltration patterns of a landscape are also
altered by agriculture and land tillage. Water that would have absorbed
straight into the soil in normal settings now flows off into streams.

Slope of the land: Water falling on steeply-sloped land runs off more quickly
and infiltrates less than water falling on flat land.

Evapotranspiration: Some infiltration remains close to the earth surface,
where plants establish their roots. Plants require this shallow ground water to
flourish, and water is returned to the atmosphere through evapotranspiration.

2.3.3 Infiltration Rate & Soil Texture Relationship

Water infiltration, permeability, and water-holding capacity are all influenced
by the texture and structure of the soil. Soil has the ability to allow water to
pass through microscopic voids and permeate the surface. The size and
management of this microscopic vacuum determine the efficacy of soil as a
water transfer agent.

The proportion of small, medium, and big particles (clay, silt, and sand,
respectively) in a certain soil mass is referred to as soil texture. A coarse soil,
for example, is sand or loamy sand, while a medium soil is a loam, silt loam, or
silt, and a fine soil is a sandy clay, silty clay, or clay.

The arrangement of soil particles (sand, silt, and clay) into stable units termed
aggregates, which give soil its structure, is referred to as soil structure.
Aggregates can be loose and flimsy, or they can be organised into distinct,
consistent patterns.

Water infiltration is the movement of water from the soil surface into the soil
profile. Soil texture, soil structure, and slope have the largest impact on
infiltration rate. Water moves by gravity into the open pore spaces in the soil,
and the size of the soil particles and their spacing determines how much water
can flow in. Wide pore spacing at the soil surface increases the rate of water
infiltration, so coarse soils have a higher infiltration rate than fine soils.

Infiltration rate is higher at the beginning of rainfall @ irrigation, and decrease
when the soil moisture increased.

Irrigation efficiency of a system is determined by infiltration rate. If the
infiltration rate is lower than the water application, part of the supplied
moisture is lost through evaporation and runoff.

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