Witt, Torsten, Robinson, Nicole, Palma, Ana C., Cernusak, Lucas A., Pratt, Steven, Redding, Matthew, Batstone, Damien J., Schmidt, Susanne, and Laycock, Bronwyn (2024) Evaluating novel biodegradable polymer matrix fertilizers for nitrogen‐efficient agriculture. Journal of Environmental Quality, 53 (3). pp. 287-299.

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Abstract

Enhanced efficiency fertilizers (EEFs) can reduce nitrogen (N) losses in temperate agriculture but are less effective in the tropics. We aimed to design a new EEF and evaluate their performance in simple-to-complex tests with tropical soils and crops. We melt-extruded urea at different loadings into biodegradable polymer matrix composites using biodegradable polyhydroxyalkanoate (PHA) or polybutylene adipate-co-terephthalate (PBAT) polymers with urea distributed throughout the pellet. These contrast with commercially coated EEF that have a polymer-coated urea core. We hypothesized that matrix fertilizers would have an intermediate N release rate compared to fast release from urea or slow release from coated EEF. Nitrogen release rates in water and sand–soil columns confirmed that the matrix fertilizer formulations had a more progressive N release than a coated EEF. A more complex picture emerged from testing sorghum [Sorghum bicolor (L.) Moench] grown to maturity in large soil pots, as the different formulations resulted in minor differences in plant N accumulation and grain production. This confirms the need to consider soil interactions, microbial processes, crop physiology, and phenology for evaluating fertilizer performance. Promisingly, crop δ15N signatures emerged as an integrated measure of efficacy, tracking likely N conversions and losses. The three complementary evaluations combine the advantages of standardized high-throughput screening and more resource-intensive and realistic testing in a plant-soil system. We conclude that melt-blended biodegradable polymer matrix fertilizers show promise as EEF because they can be designed toward more abiotically or more microbially driven N release by selecting biopolymer type and N loading rate.

Item ID:	85904
Item Type:	Article (Research - C1)
ISSN:	1537-2537
Copyright Information:	This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. © 2024 The Authors. Journal of Environmental Quality published by Wiley Periodicals LLC on behalf of American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America.
Date Deposited:	19 Jun 2025 00:28
FoR Codes:	30 AGRICULTURAL, VETERINARY AND FOOD SCIENCES > 3002 Agriculture, land and farm management > 300204 Agricultural management of nutrients @ 100%
SEO Codes:	28 EXPANDING KNOWLEDGE > 2801 Expanding knowledge > 280101 Expanding knowledge in the agricultural, food and veterinary sciences @ 100%
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