Polyacrylamide Treatment Research Articles

The effect of polyacrylamide on runoff, erosion, and cotton yield from fields irrigated with moving sprinkler systems

Irrigation with self-propelled moving sprinkler irrigation system (MSIS) enhances seal formation at the soil surface and results in large amounts of runoff and erosion which are aggravated by the MSIS high water application rate and reflected in lower yields. The effect of polyacrylamide (PAM) application (at the equivalent rate of 20 kg ha-1), prior to the irrigation season, on runoff and erosion from bare soil and soil covered with a crop, as well as on cotton yield was studied in a clay loam vertisol (Typic Chromoxert) and a silt loam loess (Calcic Haploxeralf). A center pivot and a lateral MSIS were used in the vertisol and loess, respectively. Vegetative growth of cotton plants in the vertisol was inversely related to water application intensity, which in turn affects runoff. PAM significantly reduced runoff in both the bare and crop-covered soils. The runoff level from the PAM treatments was 50–70% of that of the control. PAM also reduced erosion especially in the vertisol soil. However, the amount of eroded material carried by a unit runoff was similar in both treatments for both soils, indicating that PAM influences erosion by reducing runoff levels. A trend whereby PAM increased yield of cotton (Gossypium hirsutum L., cv. Pima S5) compared with the control was observed. Our results suggest that, under irrigation with a MSIS, reducing runoff is essential for obtaining higher yields. PAM is suggested as an effective tool to attain this target.

Effects of polyacrylamide on some biological and physical features of soil: Preliminary results from a greenhouse Study

Abstract The objective of the study was to observe the effects of polyacrylamide (PAM) additions on seed germination, nematode populations, and some soil physical properties. A month‐long greenhouse study was undertaken using 0.2% PAM in a coarse‐silty, carbonatic, mesic Typic Heploxeroll seeded with Bromus tectorum. Seedling emergence and plant biomass were monitored directly. Nematode densities, bulk density, and penetrometer resistance were measured in conventional ways. Soil water loss was measured gravimetrically. Soil cracking was described by photographic means. No significance was detected between treatments and controls in respect to seedling emergence, biomass, and water loss. However, significantly greater penetrometer resistance was observed following the PAM treatments. Greater nematode densities occurred in the controls, as did soil cracking. PAM may, because of soil binding characteristics, restrict nematode activity directly or indirectly through other microflora and fauna they would feed ...

Field studies on effect of soil conditioners and mulch on runoff lrom kaolinitic and illitic soils

Runoff plots (1 - 5 m2) were constructed at three sites where crusting, runoff and erosion are severe problems. The effect of surface application of phosphogypsum (PG), polyacrylamide (PAM) and mulch cover on runoff during natural rainstorms were studied. Runoff percentage from control (bare) plots in some rainstorms exceeded 90% of the rainfall. The annual runoff from control plots ranged between 33 and 73% of the annual rain. Mulch was highly beneficial in reducing runoff, indicating that seal formation restricted water penetration rather than hydraulic properties of the profile. PG reduced runoff to 0.15-0.82 of the untreated plots. The efficiency of PG in reducing runoff was inversely correlated with rainstorm intensity. The beneficial effect of PC in reducing runoff lasted throughout the rainy season. Its beneficial effect terminated during the consecutive season in the Irene site when the cumulative rain depth exceeded 700 mm. PAM treatment reduced annual runoff by two to three fold in comparison with the control treatment. The effect of PAM on diminishing runoff in the rainfall simulator studies was more pronounced than in the field conditions.

WATER QUALITY AND PAM INTERACTIONS IN REDUCING SURFACE SEALING

Seals formed at the soil surface during rainstorms reduce rain penetration and cause runoff and erosion. We studied the effect of surface application of an anionic polyacrylamide (PAM) at rates of 10, 20, and 40 kg.ha-1 on the infiltration rate (IR) of two soils, a loess (Calcic Haploxeralf) and a grumusol (Typic Chromoxerert), during simulated rainstorms. We determined the interaction between PAM and electrolyte concentration at the soil surface under a simulated rainfall of distilled water or tap water and by spreading gypsum. Electrolytes in the soil solutions that flocculated the soil clay enhanced the beneficial effect of the polymer on aggregate stability and greatly reduced water losses. Complete drying of the polymer-soil surfaces improved the binding action of the polymer. Treatments with PAM under optimal conditions increased the final IR of the loess from 2.0 to 23.5 mm.h-1 and increased rain intake of an 80-mm rainstorm from 12.3 to 64.2 mm. PAM treatment of the grumusol increased the final IR from 3.0 in the control to 20.5 mm.h-1 and the rain intake from 21.3 to 62.3 mm. As soils from semiarid regions are unstable, form crusts, and produce much runoff (80%) during rainstorms, the use of PAM to reduce runoff should be considered.

EFFECT OF POLYACRYLAMIDE ON SEEDLING EMERGENCE OF THREE GRASS SPECIES

We performed two greenhouse trials to determine the effects of 0, 0.2, 2.0, 20.0, and 200.0 kg ha−1 of polyacrylamide (PAM), a soil conditioner, on seedling emergence of sideoats grama (Bouteloua curtipendula [Michx.] Torr.), alkali sacaton (Sporobolous airoides [Torr.] Torr.), and Boer lovegrass (Erogrostis chloromelas Steud.). The pots of the first experiment were irrigated every 5 d, and pots in the second experiment were irrigated every 8 d. A soil with unfavorable physical conditions and with a history of crusting was used as a support medium. Shear strength and water infiltration were also evaluated. Emergence of 100% within 22 d of planting for sideoats grama was obtained in experiment 1 with 200 kg ha−1 PAM application. As expected, the real effect of PAM was more noticeable in the second experiment, where emergence of 100% was noted for both 20− and 200-kg-ha−1 PAM applications, though only 50% emergence occurred in control pots. No significant differences in seedling emergence were found for alkali sacaton in experiment 1. In experiment 2, however, significantly more seedlings were obtained in PAM treatments than in the control pots. Plants of alkali sacaton became desiccated 1 month after emergence. Boer lovegrass emergence was not improved with PAM applications in experiment 1, but in experiment 2, more seedlings were obtained with PAM applications. Like plants of alkali sacaton, Boer lovegrass began desiccating 1 mo after emergence. Values of shear strength showed that PAM worked well as an anticrustant amendment. In general, as PAM rates increased, shear strength values decreased. Infiltration rates did not show a clear trend; infiltration was improved in experiment 1, but no effect was noted for experiment 2. It seems reasonable to conclude that application of PAM may be a viable method of assuring good stand development of seeded grasses on crusting range soils.