Research
Modelling the Plant Silicon Hydraulic Capacitance and Passive Uptake under Drought and Saline Conditions
Silicon is the second abundant element in the earth’s crust and may also exist in sufficient amounts in groundwater. The sprinkler irrigation with groundwater increases the silicic acid in soil water and therefore silicon uptake by plant root especially under abiotic stress conditions. As the silicon uptake process is mainly passive with mass flow, the soil water hydraulic capacitance was modified to express the process of silicon passive uptake because each soil skeleton has its unique concentration of silica due to its mineralogical decomposition. Silicon like hydraulic capacitance, Β_Si represents the fast reservoir of the soluble form of silica ready for root uptake and translocation to do its best for combating the adverse impacts of global climatic changes on the agro ecosystem’s continuum such as water and nutrients deficits, salinity stress, heat sock, and diseases. AMUN_SiHC model which is created to calculate the soil water hydraulic capacitance, siliconlike hydraulic capacitance, water and silicon passive uptake, was derived, run, and discussed
The Modified Richardos Equation for Assessing the Impact of Drought and Salinity in Arid and Semi-Arid Zones. Part Two A Soil Hydraulic Capacitance
A soil hydraulic capacitance is a new physical property related to the interactions between the agro eco-system components soil, water, plant and atmosphere. It gives new quantitative details about the processes control the plant water uptake, ascending of sap and soil response toward the root water uptake under a certain soil moisture regime and climatic changes. The soil hydraulic capacitance, a tank like a plant water reservoir, is being controlled by signals, valves like switches. Three types of signaling devices, Geo, Bio, and weather controlled were discussed. The soil hydraulic capacitance property was first discovered by the author when modeling the wheat root water uptake under saline and drought conditions. Under the latter extreme conditions, treating plants with silica products was the managerial practice used for enhanced plant growth and water uptake. A split-split plot experimental design with four replicates was used to conduct the research in Oraby Village, Maryout area, Alexandria, Egypt in the last year of the most water-scarce decade. The aim of the experiment was to put the sink/ source term of Richard’s equation, S, into investigation under a macroscopic electrical modeling, AMUN_SHC. Natural drought and salinity stressors are the abiotic extremes. Silicon foliar applications are the managerial practices used for combating the latter extremes. The Plant stress index, soil stress index and strain of straw sap were calculated. The S-shaped relative extreme response function was used to describe the SSI=f (h, z, t). the effect of silicon as a beneficial element on the soil hydraulic capacitance and therefore the winter wheat water uptake was estimated and discussed. The soil hydraulic capacitance equations were derived and discussed. The brilliant result from the research is that the soil hydraulic capacitance, a recently discovered soil hydro-physical property, controls the root water uptake under drought and saline conditions in accordance with stress, strain and weathered controlled relationships.
