Principles of Soil and Plant Water Relations POSTED  JUNE 13, 2019   JLI SOCIAL MEDIA Soil Water System The plant needs soil and water for its growth. The soil anchors the plant and allows the root system to grow. Soil consists of a three-phase system – solid, liquid and gas. The complex mass of organic and mineral matter acts as a matrix consisting of a number of pores of various sizes. The void space within the particles is known as soil pore space. The pores of the soil hold moisture attached to the soil particle by surface tension. If water is present in amounts more than that can be stored, the soil expels air. On the other hand, in dry soils, the water molecules are present as a thin film around the soil particles Classification of Soil Water Water occurs in varying proportions in the soil pores. Based on the physical factors, the water held in the pores can be defined as: When a soil sample is saturated with water and allowed to drain the amounts that are present in excess, the