Insensitive munitions (IM) are a new class of explosives that are increasingly being adopted by the military. The ability of soil microbial communities to degrade IMs is relatively unknown. In this study, microbial communities from a wide range of soils were tested in microcosms for their ability to degrade the IM, 3-nitro-1,2,4-triazol-5-one (NTO). All seven soil inocula tested were able to readily reduce NTO to 3-amino-1,2,4-triazol-5-one (ATO) via 3-hydroxyamino-1,2,4-triazol-5-one (HTO), under anaerobic conditions with H2 as an electron donor. Numerous other electron donors were shown to be suitable for NTO-reducing bacteria. The addition of a small amount of yeast extract (10 mg/L) was critical to diminish lag times and increased the biotransformation rate of NTO in nearly all cases indicating yeast extract provided important nutrients for NTO-reducing bacteria. The main biotransformation product, ATO, was degradable only in aerobic conditions, as evidenced by a rise in the inorganic nitrogen species nitrite and nitrate, indicative of nitrogen-mineralization. NTO was nonbiodegradable in aerobic microcosms with all soil inocula.

Recent studies have begun to assess the environmental fate and toxicity of 2,4-dinitroanisole (DNAN), an insensitive munition compound of interest to defense agencies. Aerobic and anaerobic DNAN biotransformation in soils was evaluated in this study. Under aerobic conditions, there was little evidence of transformation; most observed removal was attributed to adsorption and subsequent slow chemical reactions. Under anaerobic conditions, DNAN was reductively (bio)transformed and the rate of the transformation was positively correlated with soil organic carbon (OC) up to a threshold of 2.07% OC. H2 addition enhanced the nitroreduction rate compared to endogenous treatments lacking H2. Heat-killed treatments provided rates similar to the endogenous treatment, suggesting that abiotic factors play a role in DNAN reduction. Ten (bio)transformation products were detected by high-resolution mass spectrometry. The proposed transformation pathway involves reduction of DNAN to aromatic amines, with putative reactive nitroso-intermediates coupling with the amines to form azo dimers. Secondary reactions include N-alkyl substitution, O-demethylation (sometimes followed by dehydroxylation), and removal of an N-containing group. Globally, our results suggest that the main reaction DNAN undergoes in anaerobic soils is nitroreduction to 2-methoxy-5-nitroaniline (MENA) and 2,4-diaminoanisole (DAAN), followed by anaerobic coupling reactions yielding azo-dimers. The dimers were subsequently subject to further (bio)transformations.

Environmental context Insensitive munitions compounds are increasingly used in the manufacture of military energetic materials because of their lower unintentional explosion risk during transport and handling. The current study was designed to better resolve the environmental chemistry of two of these insensitive munitions compounds. In particular, we investigated the solid–solution partitioning that occurs when aqueous solutions containing dissolved unexploded ordinances come into contact with soil mineral media. Abstract Insensitive munitions compounds (IMCs) are increasingly used for military energetic materials, yet their environmental fate is poorly understood. Prior work has shown that the nitroaromatic 2,4-dinitroanisole (DNAN) and the heterocyclic nitrogen compound 3-nitro-1,2,4-triazole-5-one (NTO), both newly introduced IMCs, can undergo microbially mediated reduction under anoxic conditions to form 2-methoxy-5-nitroaniline (MENA) and 3-amino-1,2,4,triazole-5-one (ATO) respectively. In the present work, DNAN, MENA, NTO and ATO were subjected to batch adsorption–desorption experiments with specimen soil mineral adsorbents that included montmorillonite, birnessite and goethite. DNAN and MENA exhibited high affinity, linear adsorption to montmorillonite, with enhanced surface excess at a given aqueous equilibrium concentration for K+-saturated relative to Na+-saturated forms, but negligible adsorption to the metal oxides. Powder X-ray diffraction data and surface occupancy calculations indicate interlayer intrusion by DNAN and MENA and adsorption at siloxane sites. Conversely, NTO and ATO exhibited low sorptive affinity and apparent anion exclusion upon reaction with the negatively charged layer silicate clays. However, both of the N-heterocycles showed positive adsorption affinities for goethite (Kd values of 11.1 and 3.1, and HI values of 1.8 and 0.50 respectively), consistent with anion adsorption to the positively charged goethite surface. Both ATO and MENA were subjected to apparent oxidative, abiotic chemical transformation during reaction with birnessite. The results indicate that the IMCs studied will exhibit adsorptive retardation – and their biodegradation products may undergo further abiotic transformation – upon reaction at soil mineral surfaces.

This article highlights the importance of raising soil organic matter in sandy and calcareous soils as it relates to increasing the water holding capacity of the soil. Farming in Florida on sandy soils has numerous limiting factors; one of which is it's low water holding capacity. By raising the soil organic matter content by just 1% can have a significant increase in soil water holding capacity. This would mean that soil would be able to hold more water for long durations. The prospect of increasiong water holding capacity in soils is great for agricultural productivity, and can have a significant impact on water conservation and usage.

Phosphorus management in reduced-tillage systems is a great concern for farmers. Conclusive positive results of deep-banding P fertilizers compared with broadcast application and the chemistry of reduced-tillage systems remain unclear. Knowledge of the dominant solid P species present in soil following application of P fertilizers and the resulting potential P availability would help us understand and efficiently manage P in reducedtillage systems. The objective of this research was to study the influence of placement (broadcast vs. deep-band P), fertilizer source (granular vs. liquid P), and time on the reaction products of P under field conditions. Changes in soil pH, resin-extractable P, total P, and speciation of P were determined at different distances from the point of fertilizer application at 5 wk and 6 mo after P application at a rate of 75 kg ha -1 to a soil system that was under long-term reduced tillage. Resin-extractable P was lower for broadcast treatments compared with deep-band treatments for both time periods. Resin-extractable P was greater in the liquid P-treated soils than in the granular P-treated soils. Speciation results showed that granular P fertilizers tended to form Fe-P-like forms, whereas liquid forms remained in adsorbed P-like forms in the soil 5 wk after application; moreover, speciation results showed granular P fertilizers precipitated less when deep-banded. During the 6-mo period following application, reaction products of broadcast granular, broadcast liquid, and deep-band granular fertilizers transformed to Ca-phosphate or mixtures of Ca-, Fe-and adsorbed-phosphate-like forms, whereas deep-band liquid P remained as mainly adsorbed P-like forms. Deepbanding of P would most likely provide a solution that is both agronomically and environmentally efficient for reduced-till farmers.Abbreviations: LC, linear combination; MAP, monoammonium phosphate; PCA, principal component analysis; XANES, X-ray absorption near edge structure.