Porosity change model for watered super absorbent polymer-treated soil

Abstract

Drought is a great concern in agricultural production, because it restricts normal plant growth, brings about enormous economic loss and deteriorates ecological environment. Proper use of super absorbent polymers (SAP) is helpful in the agricultural and horticultural industry in arid and semi-arid areas, because SAP can ease the burden of water shortage. Because porosity is one of the most important soil physical properties, it is a priority to study SAP to quantitatively express the swelling of watered SAPtreated soil. This study was aimed to evaluate the bulk density curve of watered SAP-treated soil and to construct and test the model for porosity change of watered SAPtreated soil. The results showed that the application of SAP can reduce soil bulk density, improve soil permeability and cause soil swelling. In addition, using three factors, i.e., water content, change in swelling ratio and SAP application rate, the paper constructed a model for porosity change of watered SAP-treated soil, which is {ln[(P m -P)(P m -This is a generic model. Two soil samples, namely, loam and sandy loam, were used to calculate the parameters and test the model. The results of the model were satisfying, thus this model is reliable.

Superabsorbent Polymer Properties and Concentration Effects on Water Retention under Drying Conditions

“…These problems require the use of an integrated approach that includes agronomic water-saving techniques, and appropriate management practices (Huang et al, 2003;Yu et al, 2011). The use of water absorbing polymers (i.e., hydrogels) or superabsorbent polymers (SAPs) such as polyacrylates cross-linked with polyacrylamides (PAM) can effectively improve the top soil's ability to store water available for plant growth and production (Buchholz, 1998;Burke et al, 2010;Yu et al, 2011), and reduce seepage of water, and fertilizer and heavy metal leaching down the soil profile (Lentz, 2007;Qu and Varennes, 2009).Mixing SAPs with soils has been found to (i) decrease soil bulk density (similar to organic matter function) and penetration resistance, (ii) increase soil aggregation, porosity, aeration and water retention capacity (Huttermann et al, 1999;Akhter et al, 2004;Busscher et al, 2009;Bai et al, 2010;Han et al, 2010), (iii) decrease soil saturated hydraulic conductivity and drainage (Abedi-Koupai et al, 2008;Andry et al, 2009;Bhardwaj et al, 2007), and (iv) serve as a source of slow release of nutri- …”

“…Mixing SAPs with soils has been found to (i) decrease soil bulk density (similar to organic matter function) and penetration resistance, (ii) increase soil aggregation, porosity, aeration and water retention capacity (Huttermann et al, 1999;Akhter et al, 2004;Busscher et al, 2009;Bai et al, 2010;Han et al, 2010), (iii) decrease soil saturated hydraulic conductivity and drainage (Abedi-Koupai et al, 2008;Andry et al, 2009;Bhardwaj et al, 2007), and (iv) serve as a source of slow release of nutri- …”

“…Mixing SAPs with soils has been found to (i) decrease soil bulk density (similar to organic matter function) and penetration resistance, (ii) increase soil aggregation, porosity, aeration and water retention capacity (Huttermann et al, 1999;Akhter et al, 2004;Busscher et al, 2009;Bai et al, 2010;Han et al, 2010), (iii) decrease soil saturated hydraulic conductivity and drainage (Abedi- Koupai et al, 2008;Andry et al, 2009;Bhardwaj et al, 2007), and (iv) serve as a source of slow release of nutri-ents, and reduce plant sensitivity to soil salinity (Liu et al, 2006;Teodorescu et al, 2009;Dorraji et al, 2010;Qu and Varennes, 2009). The application of SAP increased soil water content at field capacity and at permanent wilting point, which may lead to a considerable increase in available water content in soils of different texture used under various crops' management (Karimi et al, 2009;Agaba et al, 2010;Shahid et al, 2012;Banedjschafie and Durner, 2015;Montesano et al, 2015).…”

“…However, SAPs as soil additives have not been widely used on field-scale in agriculture, possibly because of the uncertainty regarding (i) the high cost of the SAPs, (ii) the effects of applying SAPs on water availability and crop yields (Kim and Nadarajah, 2008;Bhardwaj et al, 2009;Yu et al, 2011;Langaroodi et al, 2013), and (iii) SAP longevity in soils with respect to its water retention ability (Sivapalan, 2006;Lentz, 2007;Busscher et al, 2009;Han et al, 2010;Yu et al, 2012). Some studies have shown that addition of SAPs reduces the sensitivity of plants to water shortage and increases crop production (Silberbush et al, 1993;Singh, 1998;Viero et al, 2002;Han et al, 2005) or at least enhances plant growth at the early stages of production (Frantz et al, 2005).…”

Synthesis, Properties, and Humidity Resistance Enhancement of Biodegradable Cellulose-Containing Superabsorbent Polymer

“…The superabsorbent polymer is superior to other absorbing materials [5,6]. It has been widely used in many fields such as diapers, sanitary napkins, oilfield chemistry, and water soluble coatings [7][8][9][10].…”