Anionic polyacrylamides soil conditioners
Jozef Kollr
Polymeric soil conditioners, were known since the 1950s. These polymers were developed to improve the physical properties of soil in view of:increasing their water holding capacityincreasing water use efficiencyenhancing soil permeability and infiltration rates reducing irrigation frequencystopping erosion and water runoffreduce fertilizer and pesticides lossesReasons: most of the studies with polymers were performed in the laboratory without consideration for the economics at the production level in large scale agriculturecomplexity of application and poor distribution in the soilWide commercial application failed even though the scientific basis for their use was quite well established.
The most commonly used water-soluble synthetic soil-conditioning polymers included: poly(ethylene glycol) poly(vinyl alcohol) polyacrylates polyacrylamidepoly(isobutylene maleic anhydride)poly(maleic anhydride-co-vinyl acetate)
Gel forming polymers or insoluble water absorbing polymers were first introduced for agricultural use in the early 1980s. These polymers do not possess linear chain structures as described previously but the chains are rather crosslinked to form a three dimensional network. Gel forming polymersAdvantagesGreat water absorbing propertiesAmount of crosslinker influenced a mechanical properties of hydrogelsReduce water stress of plants Hydrogels are also claimed to reduce fertilizer leaching
Polyacrylamide (PAM) is one of the most widely employed soil conditionerAdvantages Low toxicity Safe Inexpensive Relatively stablePAMMore recently, polyelectrolytes such as acrylamide/acrylate copolymers have attracted much attention as they have been shown to be most effective in improving the properties of soils. poly(acrylamide-co-acrylic acid)
Reduce surface sealing
Increase seedling emergence
Reduce runoff and erosion
Reduce fertilizer and pesticides losses
PAM as soil conditionerPrinciple of adhering PAM molecule to soil particlesThe adsorption of PAM to soil particles depends on both the polymer and the soil properties. PAM differ with respect to molecular weight, charge density and charge type.
Polyacrylamide TypesEmulsionGranularSolid
PAM can be used in furrow or sprinkler irrigationfurrow irrigationsprinkler irrigation
PAM in furrow and sprinkler irrigation
Reduces soil loss
Prevent the loss of nutrients
Increase infiltration
Improvement of aggregate stability
Increase quality of soil as well as water
PAM treated furrow following irrigationUntreated furrow following irrigation
Synthesis of poly(acrylamide-co-tulipalin) hydrogels with crosslinker BIS
-methylene--butyrolactone also known as Tulipalin A, is present in white tulips and is identified as a substance with fungitoxic activity.
Swelling capacity in waterdry hydrogelswollen hydogel
Swelling capacity in water
Rheology of hydrogelsRheology is study of deformation and flow of material prediction of viscoelastic properties of polymers.
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