7a WHAT ARE physical properties

PROPERTIES WHAT IS IT? WHY IS IT IMPORTANT? these Texture The size of soil particles, affects soil behavior, in particular its soil properties , and , retention capacity for nutrients and water. affect soil function. determines the let’s take a look at what texture of a soil. they are and why they are important. let’s start with physical soil properties Structure The clumping of the soil The affects aeration, water movement, textural components of sand, conduction of heat, plant growth and resistance silt and clay forms aggregates to . Water has the strongest effect on soil and the further association structure due to its solution and precipitation of of those aggregates into and its effect on plant growth. larger units forms soil structures called peds.

Porosity Pore space is that part of The air space is needed to supply oxygen to plant the bulk volume that is and soil organisms. Pore space also allows not occupied by either the movement and storage of water and dissolved or organic matter nutrients. but is open space occupied by either air or water. Ideally, the total pore space should be about half of the soil volume.

Water is the downward Infiltration indicates the soil’s ability to allow water infiltration entry of water into the soil. movement into and through the soil profile. Soil temporarily stores water, making it available for root uptake, plant growth and habitat for soil organisms.

many of PHYSICAL these properties can be easily measured using simple tools check Color is caused by the minerals present and by Soil color does not affect the behavior and use of soil; the organic matter content. Soil can exhibit a wide however, it can indicate the composition of the out the soil testing range of color; grey, black, white, reds, browns, soil and give clues to the conditions that the soil is methods manual! yellows and under the right conditions green. Soil subjected to. color is described by using general terms such as “dark brown” but can also be described more technically using Munsell soil color charts.

Soil , also known Soil moisture or is important as it serves moisture as , is the as a carrier of plant nutrients, to regulate soil quantity of water temperature, to assist microbial activity and many contained in soil. more crucial activities that are essential for plant growth.

Soil Testing MANUAL Methods Compaction Refers to the increase in impairs and impedes

Soil Testing Methods soil bulk density/decrease roots penetration and water and gas exchange. Soil Doctors Global Programme in soil porosity. A farmer-to-farmer MANUAL training programme

Did you

know that soil

CA7164EN/1/12.19 © FAO, 2019 © FAO, Thanks to the financial support of compaction can reduce crop yields by as much as 60%?