Effect of long term application of super absorbent polymer on soil structure, soil enzyme activity, photosynthetic characteristics, water and nitrogen use of winter wheat

Abstract

IntroductionWater scarcity and seasonal drought are major constraints on agricultural development globally. Super absorbent polymer (SAP) is a good amendment that can improve soil structure, increase soil water retention, and promote crop growth even with less soil moisture. We hypothesize that long term application of SAP has a better effect on soil organic carbon, soil enzyme activity, photosynthetic characteristics, yield, and water and nitrogen use than short term application. MethodsA long term field experiment with different application rates (0 (CK), 15 (L), 30 (M), 45 (H) kg ha-1) of SAP was conducted at the Yuzhou water conservation agriculture base of the Henan Academy of Agricultural Sciences from 2011 to 2019.Results and DiscussionThe results indicate that applying SAP increases > 0.25 mm aggregates and decreased<0.25 mm aggregates in the soil after one year (2011) and 9 years (2019) of application. In addition, soil organic carbon, soil microbial biomass carbon, soil sucrase and cellulase activities, soil water consumption, water consumption, net photosynthetic rate (Pn), leaf water use efficiency (LWUE) of wheat and yield, all increased after SAP application. SAP also boosts water use efficiency and nitrogen use efficiency. Correlation analyses show that SAP promotes the growth of wheat, and improves the utilization rate of soil water and nutrients by improving the soil structure and increasing soil organic carbon and microbial enzyme activity.ConclusionBased on our research, SAP treatment at a dosage of 45 kg ha-1 is most effective and is thus recommended.

High-Toughness and High-Transparency Recyclable Poly(vinyl alcohol)-Based Organic–Inorganic Composite Membranes

“…Facing the problems of increasingly depleted water resources and seasonal droughts, improving soil water retention is one of the priorities for global agricultural development . In general, better soil moisture retention capacity needed for crop growth should be provided in order to improve crop yields .…”

“…Facing the problems of increasingly depleted water resources and seasonal droughts, improving soil water retention is one of the priorities for global agricultural development. 61 In general, better soil moisture retention capacity needed for crop growth should be provided in order to improve crop yields. 62 By simulating the water loss rate of soils with and without composite membranes in pots in the laboratory, as shown in Figure 13, soil water loss increased progressively over time, with those covered by PVA and PP2S2 membranes losing significantly less water than the control (CK), where PP2S2 cover resulted in lower soil water loss, which was only 9.6133 ± 0.51% after 10 days of soil monitoring.…”

Long‐term combined subsoiling and straw mulching conserves water and improves agricultural soil properties

“…Reducing this mechanical damage prevents the infiltration capacity of the soil from gradually decreasing over time, and prevents deeper soil from drying out due to a lack of percolation. SS is thus beneficial for crop root growth, organic carbon content, and soil organism activity (Li et al, 2018) especially for the combination of subsoiling with organic fertilizer (Yang, Duan, et al, 2022; Yang, Li, et al, 2022; Yang, Wu, et al, 2022) and straw mulching with organic fertilizer (Yang et al, 2023). In addition, compared to CS, SS improved soil pore circularity especially in the uppermost 50 cm of the soil (Figure 3), which allows moisture to be better retained and transported by the soil.…”

“…The addition of straw to the soil may also increase the fertility, permeability, and moisture retention characteristics of the soil (Xu, 2019) while inhibiting weed growth. Combining straw application with other farming techniques that also improve the soil may lead to overall better soil quality and thereby promote soil sustainability and soil moisture conservation, and increase crop yields and water use efficiency, which helps conserve water (Yang, Duan, et al, 2022; Yang, Li, et al, 2022; Yang, Wu, et al, 2022; Yang et al, 2023; Zhang et al, 2023).…”

“…However, Schneider et al (2017) found that subsoiling could decrease crop yield due to nutrient leaching by high infiltration rates, which may result from differences in soil types. In addition, Yang, Duan, et al (2022), Yang, Li, et al (2022), Yang, Wu, et al (2022) and Yang et al (2023) found that subsoiling combined with organic fertilizer, and straw mulching coupled with organic fertilizer, both improved soil properties and soil organism activities, which led to increased crop yields. The effects on agricultural soil properties of straw mulching after long‐term subsoiling tillage, or after long‐term conventional tillage, have not been sufficiently researched.…”