The effect of irrigation water quality and moisture content in the processing power of potassium under conditions of protected agriculture


Trial was conducted at plastic house in College of Agriculture –University ofBaghdad at winter season of 2009-2010. The trial includedtwotreatments: -the firstwas irrigation water quality (river water, drainage water and mixed water -50%riverwater + 50% drainage water) and the second was water moisture levels (irrigation at40, 60, 80 % of available water).Tomato transplants were planted in the plastichouse using drip system to apply irrigation water. Laboratory experiments wereconducted on the soil before, during and after growth season to investigate thethermodynamic behavior of potassium using quantity- intensity relationship.Results showed that the lowest values of labile K were found at early yield stagecomparing with values at flowering stage and the end of the season stages whichindicate the role of the crop in depletion of soil K. To control K supply, the nutrientshould be added before early yield stage. Releasing K was higher from soil irrigatedwith river comparing with mixed and drainage water. Moisture level of 40%available water give higher values of LK. Results showed that values of potassiumactivity ratio at equilibrium ARK0were reduced during plant growth comparing withthe values before planting which reflect the role of biological factor onK uptake byplant. ARK0values were higher for river water treatment comparing with mixedand drainage water.