Effect of straw and polyacrylamide on the stability of land/water ecotone soil and the field implementation

Abstract

Poor stability of land/water ecotone (L/WE) soil is a serious and increasing problem in the context of ecological restoration. Effective management by adding straw and polyacrylamide (PAM), i.e., SPAM, to soil may increase soil stability, including structure and fertility. Thus, it is important to explore the effects of SPAM on L/WE soil, as well as to determine the appropriate ratio of straw and PAM to achieve optimal increases. To investigate the soil properties and provide basis for ecological restoration, an indoor soil culture experiment, including nine straw and PAM combinations, was conducted. It was found that 3 g/kg straw with 1 g/kg PAM was optimal; thus, this scale was applied in engineering of Gonghu L/WE, which was turning Fishery to Lake. The survey explored changes in soil nutrients and structure, dry-sieved aggregate stability, and wet-sieved water aggregate stability under nine measures. Results indicated that the measurement of SPAM strongly affected soil properties, such as improvements in the fine sand and clay fraction, decreased coarse sand fraction and density, and enhanced content of the larger aggregates (>2 mm), organic matter (OM), available nitrogen (AN), available phosphorus (AP), and available potassium (AK). For soil nutrients, applying of Straw/PAM significantly improved the contents of OM/AN, respectively; showing an increasing trend with a dosage rate. Meanwhile, it was shown that SPAM was more effective than treating each individual component on AP and AK improvements. Regard-ing soil structure, application of PAM significantly increased contents of the dry-sieved aggregates and wet-sieved water-stable aggregates, especially aggregates >2 mm. Straw mulching only improved the content of dry-sieve medium size aggregates. However, when combining SPAM, the straw improved the medium particle size fraction, after which PAM converted a portion of the medium particles into >2.0 mm aggregates. Furthermore, the measure proved to be beneficial to land/water ecotone engineering.

Exploring soil amendment strategies with polyacrylamide to improve soil health and oat productivity in a dryland farming ecosystem: One‐time versus repeated annual application

“…The other reason was likely associated with the linear water‐soluble polymer with large molecular weight of PAM (Thombare et al, ). The structure of PAM is able to promote binding and adhesion or flocculation of soil particles (Lu et al, ), leading to the improved soil physical structure in the incorporation layer. Meanwhile, reduced soil mechanical impedance and enhanced aeration through decrease in SBD enhanced the SWS capacity, which potentially reduced water loss out of the rooting zone to the ground water (Laboski, Dowdy, Allmaras, & Lamb, ).…”

“…Polyacrylamide (PAM) is a synthetic polymer with a superhigh water retention capacity. It has been used as a soil amendment on construction sites and on millions of hectares of furrow irrigation lands worldwide to improve soil water‐holding capacity and stabilize soil structure, thus decreasing soil degradation and erosion (Entry, Sojka, & Hicks, ; Lu et al, ; Roshanizarmehri et al, ). It is also beneficial in reducing the runoff and nutrient loss (e.g., phosphates and nitrates), maintaining their availability to the crop plants (Entry, Sojka, Watwood, & Ross, ; Lentz, Sojka, & Robbins, ).…”

Effect of Digestate and Straw Combined Application on Maintaining Rice Production and Paddy Environment

“…As another agricultural waste, straws are rich in cellulose, hemicellulose, lignin and other carbon compounds [ 16 ]; straw production in China accounts for ~25% of the world’s total straw resource [ 17 ] and straw incorporation is considered a potential approach to improve soil fertility and even boost rice production [ 18 , 19 , 20 ]. Previous studies found that straw return could improve soil organic matter (SOM) and structural stability during degradation processes, leading to a better soil function [ 21 , 22 , 23 ]. Moreover, several studies showed that straw addition could increase the activities of soil enzymes, including urease, phosphatase and catalase [ 24 , 25 ].…”

Effects of polymer materials on the transformation and utilization of soil nitrogen and yield of wheat under drip irrigation

“…Previous studies have found that the application of polyacrylamide (PAM) reduces the loss of soil NH 4 + and NO 3 - (Li & Wang, 2016) and facilitates microbial growth and metabolism (Li et al, 2013), and the application of humic acid improves soil agglomerate structure and enhances the absorption of nitrogen by crops (Vlcková et al, 2009), increasing grain yield and total biomass (Pamela et al, 2014). However, at present, the polymer materials used in many studies are solids (Awad et al, 2012;Lu et al, 2016;Luo et al, 2015), and several researches on liquid polymer materials are only carried out in potted plants by spraying (Li & Wang, 2016;Wang et al, 2011). Therefore, in this study, three polymer materials were used to analyse their effects on the transformation and utilization of soil nitrogen combined with drip irrigation.…”