The Impact of Banding Polymer-Coated Urea on Nitrogen Availability and Distribution in Contrasting Soils

Abstract

Polymer-coated urea (PCU) has been traditionally used for broadcast and/or incorporated application of nitrogen (N) fertilizers. To improve N use efficiency (NUE), there has been an increase in sub-surface banded application of this fertilizer technology. However, there is little information on the release and supply of N from PCU granules when applied in a band. This research aimed to investigate the spatial distribution of key N transformations around PCU bands in soils of contrasting physico-chemical properties, and the implications for NUE. Two experiments, consisting of a 60-day diffusion study and a 91-day incubation, were conducted in a Vertosol and Dermosol, with PCU granules banded at a rate equivalent to 150 kg N ha−1 and band spacing of 1.8 m. Compared to standard urea, PCU provided a sustained release of urea-N to soil solution and the lower urea-N concentrations minimized the toxic conditions associated with rapid hydrolysis of urea-N. Nitrogen release from banded PCU was quicker in the Vertosol (cf. Dermosol), possibly due to a higher volumetric water content and/or greater soil particle surface contact, facilitating rapid water imbibition into granules. However, the proximity of PCU granules to each other in a band restricted the diffusive release of urea-N from PCU granules cf. dispersed application in both soils. Furthermore, the relatively mild chemical conditions in the PCU band (cf. standard urea) resulted in oxidisation of larger proportions of PCU-derived mineral N. Banded application may extend the duration of N release from PCU granules, confounding efforts to predict N availability. Soil characteristics influenced N release and dynamics from banded PCU, although further investigation is required. Higher rates of nitrification of N derived from PCU bands suggest there could be increased risk of N-loss via denitrification or leaching pathways (cf. standard urea bands) if release dynamics are not optimally synchronised with crop demand. This study provides the first mechanistic insights into the impact of application method and soil physico-chemical properties on the efficacy of PCU.

Impact of different sowing dates and irrigation levels on NPK absorption, yield and water use efficiency of maize

“…Thereafter, these soil samples were crushed and sieved through a 2-mm sieve to remove any gravel and coarse plant residues and prepared to determine the physicochemical properties and water status. Using Systronics 372 pH/EC/ TDS/Salinity meter at 25 °C, soil pH and electrical conductivity (EC) were determined and following the protocol elaborated by Janke et al 31 . Soil particle size distribution was determined using the pipette method, whereas soil textural classes were determined by using the methods developed by USDA Soil Survey Staff 32 .…”

Tillage and Straw Management Practices Influences Soil Nutrient Distribution: A Case Study from North-Eastern Romania

“…According to tillage practice, conservation tillage treatments, especially MT maximize agricultural productivity through soil structure protection [41]. Due to burying and/or mulching and less physical disturbance, MT and NT might increa proportion of macro-aggregates where greater contents of organic carbon could be f A healthy soil structure allows for reducing soil bulk density, improves soil total po and retains greater quantities of water supporting the growth of the crop [34,42]. M ver, conservation tillage lessens soil disturbance and compaction and forms stab glomerate structures thereby protecting organic carbon from mineralization and tion by reducing the access of substrates to microorganisms [43].…”

“…As the availability of Zn, Cu, Fe, and Mn may be decreased by the acidity driven by the increased level of N fertilizer treatment, stratification is a major limiting parameter for plant growth [33]. According to Janke et al, [34] tillage systems can also have consequences on soil pH, which has a significant effect on soil health and nutrient content. This suggests that maintaining agricultural productivity may depend significantly on managing soil tillage.…”

Improving crop productivity and nitrogen use efficiency using sulfur and zinc-coated urea: A review

“…To minimize N loss in changing environmental conditions, controlled/slow-release fertilizers are specially designed that can sufficiently regulate the N requirement of crops during the growing season (Janke et al, 2022).…”