Effect of Sprayable Biobased Polymers on Soybean Growth and Yield, Weed Suppression, Soil Temperature, Soil-Water, Evapotranspiration and Soil Quality Variables
Authors: Irmak Sibel , Irmak Suat , Kaur Jaspreet 
Published: December 2024

HIGHLIGHTSNovel sprayable biobased polymer (BBP) has been developed.BBP impact on soil temperature, soil water content, evapotranspiration, weed suppression, and soybean productivity were investigated.BBP moderated extreme high soil temperatures and resulted in an average of 3.4°C temperature moderation.BBP resulted in soil water conservation as compared with the control without BBP application.Weed number and weed dry matter were significantly lower with the BBP applications than the control.BBP increased nitrogen, organic matter content, and hydrogen content with no impact on sulfur content.Abstract. A novel sprayable biobased polymer (BBP) (bioplastic) has been developed from poultry feathers and woody biomass using chemical and thermochemical methods. Its potential impacts on soil temperature; soil water content (SWC); crop evapotranspiration (ETc); weed [common Waterhemp (WH) (Amaranthus tuberculatus) and Palmer Amaranth (PA) (Amaranthus palmeri)] suppression under soybean (SB) production; soybean growth, yield, number of pods, soybean dry matter production, 100-kernel number; and soil health variables [carbon (OMC), nitrogen (N), hydrogen (H), and sulfur (S) content, C/N ratio, and C/H ratio] were investigated. Treatments were WH+SB and PA+SB with and without BBP (control) applications. BBP moderated extreme high temperatures and resulted in 2.8°C moderation in the WH plots and 3.9°C in the PA plots with an average of 3.4°C. SWC values for the WH+SB and PA+SB with BBP were significantly (P &lt; 0.05) higher than those in the WH+SB and PA+SB without BBP applications, indicating soil-water conservation effect of BBP due to reduced surface soil evaporation. There were only slight differences in daily ETc between the treatments. ETc values ranged from 0.35 to 4.9, from 0.31 to 4.9, from 0.25 to 4.9, and from 0.25 to 4.8 mm/d for the control WH+SB without BBP, WH+SB with BBP, control PA+SB without BBP, and PA+SB with BBP applications, respectively. The cumulative ETc values slightly differed between the treatments and were 329, 314, 313, and 294 mm for the same treatments, respectively. BBP suppressed WH by 42% and controlled PA by 57% without any herbicide applications. Weed dry matter production in the control WH+SB without BBP, WH+SB with BBP, control PA+SB without BBP, and PA+SB with BBP applications were 30, 15, 46.3, and 19.9 gr, respectively. Both weed number and weed dry matter for WH+SB and PA+SB were significantly lower with the BBP applications than the control. Significantly greater plant height with BBP applications did not translate into significantly higher soybean productivity under WH+SB. The higher plant height and lower number of weeds in the WH+SB with BBP treatment did not result in higher soybean dry matter production, number of pods, pod weight, or 100-kernel weight. The increases in N, OMC, and H content with BBP application were significant for both WH+SB and PA+SB with BBP as compared with their controls. The increase in S content was not significant for WH+SB or PA+SB. The increase in C:N ratio due to BBP application was significant, but the change in C:H ratio was not. Experimental results showed important positive impacts of developed BBP formulations in agricultural applications with the potential to increase productivity. Further research is needed to quantify and validate these potential positive impacts of BBP for other cropping systems in different soil and climatic conditions. Keywords: Biopolymer, Soil health, Soil productivity, Soybean, Weeds.