Effect Of Potassium Fertilizers And Organic Matter Additions On Soil Available Potassium

Abstract

This experiment carried out at the soil and water sciences department , college of agriculture , university of Wasit during the season of 2019 to investigate the effect of addition different levels of organic matter , potassium fertilizers associated with two incubation periods on potassium availability in two different textures calcareous soils located in two different locations in Wasit governorate , Iraq .The two selected soils are clay loam brought from Al-Swera ,and sandy loam brought from a farm in Al-Nomanya district , four potassium levels (in basis of estimated on the which(0,100,200,300 kg/h) added at the levelswere SO4) 2form Ksample weight 100 gm, on the other hand , organic matter levels (sheep manure) were added in three levels (0% , 3% ,6%),these levels were estimated on 100 gm on the basis of soil weight too , all treatments were replicates 3 times , the results showed that there is significant difference in the values of available potassium in relation to soil type , were Al-Swera samples showed 14% available potassium higher than Alnumanya due to high clay content in former sample , also results pointed out the difference between applied potassium levels which significantly reflected on available potassium in soil , were the increase reached 108% for K3 as compared with control treatment K0, as it turned out the addition of organic matter also gave significant differences in available potassium values with the increase of addition levels , wherever higher available potassium level was achieved 754.4 ppm , The binary interaction treatment between soil type and organic matter levels achieved significant differences where the combination T1M2 surpassed (804ppm) nuances with control treatment (441.9 ppm) for Alnumanya soil, the binary interaction between soil type(T) and applied potassium levels (K) achieved significant differences where the combination K1K3 was surpassed (827.8 ppm) as compared with lowest value which achieved 323.2 ppm for the combination T2K0 also the results of second incubation period appears that Al-Swera soil surpass (T1) which achieved increase amounts to 15% in available potassium as compared with Al-Numanya soil (T2) which return to the difference of its clay content , the level K3 also surpass as compared with control treatment by achieving 105% increment percentage, there is significant increase of available potassium levels with the increase of organic matter addition as compared with no addition treatment where higher value was( 836.3 ppm) at the level (M3) while the lowest value 548.8 ppm for control treatment (M0), whereas interaction of organic matter level (M2) with fertilizer addition for the combination M2K3 which was (1003 ppm) as compared with control treatment, extending of incubation period have a role in available potassium increase in soil , there is clearly rising trend in available potassium which stood at (678.7 ppm) at the incubation period D2 which significantly differs from incubation period D1 which amounted ( 612.9 ppm) , this due to that the second incubation period provided enough opportunity to achieve equilibrium with colloids surfaces which has been clearly reflected on available potassium concentrations no matter what is the soil type.