A 13C NMR study of decomposing logging residues in an Australian hoop pine plantation

Purpose Residue retention is important for nutrient and water economy in subtropical plantation forests. We examined decomposing hoop pine (Araucaria cunninghamii Ait. Ex D. Don) residues-foliage, branches, and stem wood-to determine the changes in structural chemistry that occur during decomposition. Materials and methods Residues were incubated in situ using 0.05 m2 microplots. We used solid-state 13C nuclear magnetic resonance (NMR) spectroscopy to determine the structural composition of harvest residues in the first 24 months of decomposition. Results and discussion The spectral data for branch and stem residues were generally similar to one another and showed few changes during decomposition. The lignin content of branch and foliage residues decreased during decomposition. When residues were mixed together during decomposition, the O-alkyl fraction of foliage decreased initially then increased up to 24 months, while the alkyl carbon (C) fraction exhibited the opposite pattern. The decomposition of woody hoop pine residues (branch and stem wood) is surprisingly uniform across the major C forms elucidated with 13C NMR, with little evidence of preferential decomposition. When mixed with branch and stem materials, foliage residues showed significant short- and long-term compositional changes. This synergistic effect may be due to the C/N ratio of the treatments and the structure of the microbial decomposer community. Conclusions Twenty-four months of decomposition of hoop pine residues did not result in substantial accumulation of recalcitrant C forms, suggesting that they may not contribute to long-term C sequestration.No Full Tex

Disparities exist between National food group recommendations and the dietary intakes of women

<p>Abstract</p> <p>Background</p> <p>Preconception and pregnancy dietary intakes can influence the health of future generations. In this study we compared the food intakes of reproductive-aged women by pregnancy status, to current Australian recommendations.</p> <p>Methods</p> <p>Data are from the Australian Longitudinal Study on Women's Health, younger cohort aged 25-30 years in 2003, with self-reported status as pregnant (n = 606), trying to conceive (n = 454), given birth in the last 12 months (n = 829) or other (n = 5597). Diet was assessed using a validated 74-item food frequency questionnaire. Food group servings and nutrient intakes were compared to the Australian Guide to Healthy Eating (AGHE) and Australian Nutrient Reference Values (NRVs).</p> <p>Results</p> <p>No women met all AGHE food group recommendations. Highest adherence rates [mean (95% CI) servings/day] were for meat [85%, 1.9(1.8-1.9)], fruit [44%, 2.1(2.1-2.2)] and dairy [35%, 1.8(1.8-1.9)], with < 14% meeting remaining recommendations. Women who achieved NRVs (folate, iron, calcium, zinc, fibre) for pregnancy, breastfeeding and adult life stages were 1.5%, 3.3% and 13.7%, respectively. Compared to AGHE, women consumed more servings of fruit (4.9 vs 4.0;<it>P </it>= 0.034) and dairy (3.4 vs 2.0;<it>P </it>= 0.006) to achieve pregnancy NRVs; more dairy (2.9 vs 2.0;<it>P </it>= 0.001), less fruit (3.9 vs 5.0;<it>P </it>< .001) and vegetables (3.4 vs 7.0;<it>P </it>< .001) to achieve breastfeeding NRVs; more fruit (3.6 vs 3.0;<it>P </it>< .001), dairy (2.5 vs 2.0;<it>P </it>< .001), meat (1.8 vs 1.5;<it>P </it>= 0.015), less vegetables (3.6 vs 5.0;<it>P </it>< .001) to achieve adult NRVs.</p> <p>Conclusions</p> <p>The AGHE does not align with contemporary diets of Australian women or enable them to meet all NRVs. Current tools to guide food consumption by women during pregnancy require revision.</p