Abstract: The paper examines the mechanism of pozzolan-soil reactions, using a recent study on the chemical stabilization of a Class A-2-7 (3) lateritic soil, with corn cob ash (CCA) as case study. The objectives are to establish a nexus between cation exchange capacity of the soil, the alkaline forming compounds in CCA and percentage CCA addition to soil beyond which no more improvement in strength properties can be achieved; and to propose feasible chemical reactions to explain the chemical stabilization of the lateritic soil with CCA alone. The lateritic soil, as well as CCA of pozzolanic quality Class C were separately analysed for their metallic oxide composition using the X-Ray Fluorescence technique. The cation exchange capacity (CEC) of the soil and the CCA were computed theoretically using the percentage composition of the base cations Ca2+, Mg2+ K+ and Na2+ as 1.48 meq/100 g and 61.67 meq/100 g respectively, thus indicating a ratio of 0.024 or 2.4%. This figure, taken as the theoretical amount required to just fill up the exchangeable sites of the clay molecules, compares well with the laboratory observation of 1.5% for the optimum level of CCA addition to lateritic soil. The paper went on to present chemical reaction equations between the alkaline earth metals in the CCA and the silica in the lateritic soil to form silicates, thereby proposing an extension of the theory of mechanism of soil stabilization to cover chemical stabilization with pozzolanic ash only. The paper concluded by recommending further research on the molecular structure of soils stabilized with pozzolanic waste ash alone, with a view to confirming the chemical equations advanced in the study.
Abstract: In the area where the high quality water is not
available, unconventional water sources are used to irrigate.
Household leachate is one of the sources which are used in dry and
semi dry areas in order to water the barer trees and plants. It meets
the plants needs and also has some effects on the soil, but at the same
time it might cause some problems as well. This study in order to
evaluate the effect of using Compost leachate on the density of soil
iron in form of a statistical pattern called ''Split Plot'' by using two
main treatments, one subsidiary treatment and three repetitions of the
pattern in a three month period. The main N treatments include:
irrigation using well water as a blank treatments and the main I
treatments include: irrigation using leachate and well water
concurrently. Some subsidiary treatments were DI (Drop Irrigation)
and SDI (Sub Drop Irrigation). Then in the established plots, 36
biannual pine and cypress shrubs were randomly grown. Two months
later the treatment begins. The results revealed that there was a
significant variation between the main treatment and the instance
regarding pH decline in the soil which was related to the amount of
leachate injected into the soil. After some time and using leachate the
pH level fell, as much as 0.46 and also increased due to the great
amounts of leachate. The underneath drop irrigation ends in better
results than sub drop irrigation since it keeps the soil texture fixed.
Abstract: During this day a considerable amount of Leachate is produced with high amounts of organic material and nutrients needed plants. This study has done in order to scrutinize the effect of Leachate compost on the pH, EC and organic matter percentage in the form of statistical Factorial plan through randomizing block design with three main and two minor treatments and also three replications during three six month periods. Major treatments include N: Irrigation with the region-s well water as a control, I: Frequent irrigation with well water and Leachate, C: Mixing Leachate and water well (25 percent leachate + 75 percent ordinary well water) and secondary treatments, include DI: surface drip irrigation and SDI: sub surface drip irrigation. Results of this study indicated significant differences between treatments and also there were mixing up with the control treatment in the reduction of pH, increasing soluble salts and also increasing the organic matter percentage. This increase is proportional to the amount of added Leachate and in the treatment also proportional to higher mixture of frequent treatment. Therefore, since creating an acidic pH increases the ability to absorb some nutrient elements such as phosphorus, iron, zinc, copper and manganese are increased and the other hand, organic materials also improve many physical and chemical properties of soil are used in Leachate trash Consider health issues as refined in the green belts around cities as a liquid fertilizer recommended.