CF Treatment Research Articles

On-farm fertilizing materials in organic horticulture: agronomic performance, energy use and GHG emission evaluation

ABSTRACT Anaerobic digestate (AD), a sub-product of cattle manure treatment to produce biogas, could be used for agricultural purposes after co-composting. The aim of this research was to evaluate in organic horticulture the co-composted AD, obtained using two different aerobic stabilization processes (not aerated and aerated composting), by assessing (i) the energy requirements and the GHG emissions of on-farm co-composting; (ii) the agronomic performance of the co-composted AD, compared to a commercial organic (CF) fertilizer, on fennel, tomato and zucchini crops; (iii) the environmental sustainability of the different analyzed systems, through the energy and the carbon footprint analyses. The AD co-composting was a feasible way to valorize organic wastes by producing organic fertilizers. These fertilizers could substitute the CF, leading to similar production capacity, energetic and carbon efficiencies. In particular, despite the greater carbon stocks generated by CF, the carbon efficiency was higher in co-composted AD than CF for both fennel and tomato cultivation systems. The GHG emission analysis for the agricultural operations indicated that CF treatment determined the highest CO2 emissions. Therefore, an appropriate management of the fertilization strategies could allow reducing the GHG emissions.

Aggregate-associated changes in nutrient properties, microbial community and functions in a greenhouse vegetable field based on an eight-year fertilization experiment of China

Soil aggregation, microbial community, and functions (i.e., extracellular enzyme activities; EEAs) are critical factors affecting soil C dynamics and nutrient cycling. We assessed soil aggregate distribution, stability, nutrients, and microbial characteristics within >2, 0.25–2, 0.053–0.25, and <0.053 mm aggregates, based on an eight-year field experiment in a greenhouse vegetable field in China. The field experiment includes four treatments: 100% N fertilizer (CF), 50% substitution of N fertilizer with manure (M), straw (S), and manure plus straw (MS). The amounts of nutrient (N, P2O5, and K2O) input were equal in each treatment. Results showed higher values of mean weight diameter in organic-amended soils (M, MS, and S, 2.43–2.97) vs. CF-amended soils (1.99). Relative to CF treatment, organic amendments had positive effects on nutrient (i.e., available N, P, and soil organic C (SOC)) conditions, microbial (e.g., bacterial and fungal) growth, and EEAs in the >0.053 mm aggregates, but not in the <0.053 mm aggregates. The 0.25–0.053 mm aggregates exhibited better nutrient conditions and hydrolytic activity, while the <0.053 mm aggregates had poor nutrient conditions and higher oxidative activity among aggregates, per SOC, available N, available P, and a series of enzyme activities. These results indicated that the 0.25–0.053 mm (<0.053 mm) aggregates provide suitable microhabitats for hydrolytic (oxidative) activity. Interestingly, we found that hydrolytic and oxidative activities were mainly impacted by fertilization (58.5%, P<0.01) and aggregate fractions (50.5%, P<0.01), respectively. The hydrolytic and oxidative activities were significantly (P<0.01) associated with nutrients (SOC and available N) and pH, electrical conductivity, respectively. Furthermore, SOC, available N, and available P closely (P<0.05) affected microbial communities within >0.25, 0.25–0.053, and <0.053 mm aggregates, respectively. These findings provide several insights into microbial characteristics within aggregates under different fertilization modes in the greenhouse vegetable production system in China.

Water management affects arsenic uptake and translocation by regulating arsenic bioavailability, transporter expression and thiol metabolism in rice (Oryza sativa L.)

Water management is an economic and effective strategy to reduce arsenic (As) accumulation in rice grains, but little is known about the effect of water management on the migration and transformation of As in the soil-rice system. In this study, the effect of the continually (CF) and intermittent flooding (IF) treatments on the dynamic change of As in the rhizosphere soil-pore water-iron plaque-rice system was systematically investigated using pot experiments. The expressions of genes involved in As uptake and translocation in rice plants under different water management treatments were further examined. Results showed that the total As concentration in brown rice was increased by 50.8% in the CF treatment compared to the IF treatment, and dimethylarsinic acid (DMA) made greater contribution (from 15.5% to 29.2%) to total As increase in brown rice under the CF treatment. The CF treatment increased As bioavailability in the rhizosphere soil and soil pore water, which enhanced As uptake and transport to the xylem in rice plants by inducing the expressions of silicon transporter genes (OsLsi1 and OsLsi2) compared to the IF treatment. Moreover, the CF treatment increased As translocation from roots to shoots by reducing soil available sulfur and phytochelatins (PCs) biosynthesis and vacuolar sequestration in rice roots compared with the IF treatment. The study provides insight into the physiological and molecular mechanisms underlying As uptake and translocation in rice plants under different water regimes, which will be helpful for adopting the irrigation technique to mitigate excessive As accumulation in rice grains and associated health risk to humans.

Molecular dissolved organic matter removal by cotton-based adsorbents and characterization using high-resolution mass spectrometry

This research investigates the characteristics of dissolved organic matter (DOM) removal by synthesized cotton-fiber adsorbents using unknown screening analysis with high resolution and accurate mass spectrometry. Molecular characteristics of DOM removed by adsorbents were investigated semiquantitatively and unknown disinfection byproduct (DBP) formation potentials were also investigated. Adsorbents were modified using ferric nitrate to increase the magnetic property. The XRD pattern showed Fe-containing crystalline structures in the modified adsorbent (M-CF). The M-CF possessed higher mesopore volume, which enhanced the dissolved organic carbon (DOC) removal efficiency to 74.50% (compared to 32.12% in the unmodified CF adsorbent). The kinetics experiment showed that both adsorbents were better fitted to pseudo-second orders than pseudo-first orders. The initial rate constant was higher in M-CF (1.40 mg/g min) than in CF (0.02 mg/g min) treatments due to the higher mesopore volume in M-CF. M-CF removed almost 700 carbon‑hydrogen‑oxygen based DOMs (CHO features), 300 more CHO features than CF. CF selectively adsorbed only higher-molecular-weight (MW) CHO features (more CH2 groups), while the mesopores in M-CF removed DOM with lower MW (fewer CH2 groups) that were refractory to CF. The low MW DOM removed only by M-CF mesopore exhibited more oxidized (positive carbon oxidation state, Cos) and saturated characters (negative oxygen-subtracted double bond equivalent per carbon, (DBE-O)/C). After chlorination, over 50 unknown DBPs were detected, 33 of which were commonly found in all samples. M-CF decreased unknown formation potential more than CF. However, adsorption of M-CF and CF before chlorination resulted in different remaining precursors to water chlorination and formed unique DBPs from those precursors.

The continuous application of biochar in field: effects on P fraction, P sorption and release

It is unclear how biochar can affect P availability in soil, especially in field under continuous application. In this study, a field experiment was conducted to study the effect of 2-years application of biochar on P availability, P fractionation, P sorption and release in a clay soil. The biochar in this study was produced from rice straw through pyrolysis at 700°C. As compared with no fertilizer treatment (CK) and chemical fertilizer treatment (CF), the biochar application with chemical fertilizer treatment (BCF) significantly increased total P and available P content in soil. And BCF treatment significantly increased resin P, NaHCO3-extracted P, Fe/Al-Po and HCl-extracted P but decreased Fe/Al-Pi and residual P as compared with CF treatment. Surprisingly, BCF treatment showed higher sorption capacity and release capacity of soil P than that of CF treatment. These results imply that continuous application of biochar for 2-years in field may adsorbed P through physical sorption rather than chemical reaction and then improve P availability in soil.

Effects of reducing chemical fertilizer combined with organic amendments on ammonia-oxidizing bacteria and archaea communities in a low-fertility red paddy field.

Ammonia oxidation process in soil has a great contribution to the emission of nitrous oxide, which is a hot issue in the study of N cycle of rice field ecosystem. Organic amendments which partially substitute chemical nitrogen fertilizer are widely adopted to optimizing N management and reduce the use of chemical nitrogen fertilizers in the paddy ecosystem, but their long-term effects on ammonia-oxidizing archaea (AOA) and bacteria (AOB) were not well understood. Thus, based on a 6-year field trial that comprised four fertilization strategies (CF, chemical fertilizer; PM, pig manure substituting for 20% chemical N; BF, biogas slurry substituting for 20% chemical N; and GM, milk vetch substituting for 20% chemical N) and no N fertilizer application as CK, the abundance and community structure of ammonia oxidizers were examined by using qPCR and Illumina Miseq sequencing approaches based on the functional marker genes (amoA) in a low-fertility paddy field. The results revealed that 6 years of organic-substitute fertilization significantly increased AOA abundance in comparison with NF and CF. However, only CF and PM had a higher AOB abundance than those in NF and no significant difference between CF and organic-substitute treatments was observed. Both AOA and AOB were significantly correlated with soil potential nitrification rate (PNR). Moreover, organic-substitute treatments showed the evident changes in the AOA community, while little were observed in the AOB community. Soil pH was the main predictor for AOA abundance, while NH4+-N and NO3--N were the main predictors for AOB abundance. This study suggests that both AOA and AOB were jointly contributed to the variation of soil potential nitrification rate, while the AOA community was shown to be more responsive to organic-substitute fertilization strategies than AOB in the tested soils.

Effect of Surface Treatment of CF on the Tribological Properties of CF Reinforced Plant-Derived PA10T Biomass Composites

Effect of Surface Treatment of CF on the Tribological Properties of CF Reinforced Plant-Derived PA10T Biomass Composites

Slow-Release Fertilizer Improves the Growth, Quality, and Nutrient Utilization of Wintering Chinese Chives (Allium tuberosum Rottler ex Spreng.)

Excessive application of fertilizers leads to the loss of a high amount of nutrients and low fertilizer utilization, which severely restricts crop productivity. Establishing better fertilizer usage practices can mitigate the adverse effects of excessive fertilizer use in agricultural practices. This study determined the effects of slow-release fertilizers on the growth; quality; root and nitrate reductase activity; accumulation; distribution of nitrogen (N), phosphorus (P), and potassium (K) in roots, stems, and leaves; and NPK utilization of winter Chinese chives (Allium tuberosum Rottler ex Spreng.) in multi-layer covered plastic greenhouses. Treatments were conventional fertilization (CF, NPK: 1369.5 kg ha−1), conventional fertilization with slow-release fertilizer (SRF, NPK: 1369.5 kg ha−1), reduced fertilization with slow-release fertilizers (SRFR, NPK: 942.0 kg ha−1), and no fertilizer arranged in a completely randomized design with three replicates. The SRFR treatment increased Chinese chives yield and economic profitability by 37% and 47%, respectively, compared to the CF treatment. Similarly, nitrate reductase activity, root activity, soluble sugar, soluble protein, and flavonoid contents in the Chinese chives were increased by 40%, 12%, 16%, 6%, and 18%, respectively, in SRFR than CF. In addition to these, we observed a significant reduction in the surplus of N (42%) and P (58%) in soil under SRFR compared to CF. Nutrient uptake and nutrient use efficiency were also greater in SRFR than in CF. The results indicate that the adoption of SRFR can be an efficient approach to enhance quality and productivity of Chinese chives compared to CF under a multi-layer covered plastic greenhouse system.

Nitrous oxide emission and the related denitrifier community: A short-term response to organic manure substituting chemical fertilizer.

Partially substituting chemical fertilizer with organic manure can aid in the disposal of agricultural wastes via recycling into agricultural land, reduce chemical fertilizer application, and influence nitrogen (N) transformation. However, relatively few studies have investigated the association between soil physicochemical properties, denitrifier communities and N2O emission after short-term substitution of organic manure in vegetable fields. We conducted a short-term vegetable field experiment which included one control treatment (CT, no fertilizer) and three fertilization treatments containing equal amount of total N, phosphorus and potassium (CF, chemical fertilizer only; CMR, chemical fertilizer plus mushroom residue; COM, chemical fertilizer plus cattle manure). The results showed that partial substitution of chemical fertilizer with organic manure greatly increased cumulative N2O emissions, N2O emission factors and yield-scaled N2O emissions by 122-203%, 238-600% and 128-181%, respectively. Compared with the CF treatment, short-term substitution with organic manure reduced the abundance of nirS- and nosZ-type denitrifiers, and increased that of nirK-type denitrifiers. Modeling indicated that nirS abundance, together with soil available N, NIR activity, nirK abundance, SOC, NH4+, and NO3- were the primary factors associated with cumulative N2O emissions. The denitrifier community composition of the CF- treated soil was separated from that of soils treated with CMR and COM, and was primarily influenced by soil NH4+ concentration. NIR activity showed a significant correlation with denitrifier community composition. Overall, short-term substitution of chemical fertilizer with cattle manure (lower C/N ratio) reduced the abundance of nirS- and nosZ-type denitrifiers, but stimulated N2O emission.

Crop response and quality of soil as affected by hyperthermophilic compost in Tai-Lake region of China

A novel hyperthermophilic compost (HPC) produced from fast hyperthermophilic composting of 24 h was evaluated as a partial substitute of conventional compost (COM) and inorganic fertilization (CF) on Chinese cabbage (Brassica campestris ssp. chinensis) and chili pepper (Capsicum annuum L.) during field experiments under two soil systems. Compost characteristics were related to plant growth and soil fertility. In Anthrosols, the highest crop yield and nutrient uptake were obtained from the HPC or COM, although crop yields did not significantly (P > 0.05) differ from the yields of CF-treated soils. In the less fertile Fluvisols, crop yields were significantly higher in HPC and COM treated soils than CF treatment. Application of HPC and COM increased dissolved organic carbon (DOC), total nitrogen (N), available phosphorous (Pav.) and available potassium (Kav.) by 23.1%, 6.1%, 55.3%, 17.4%, respectively in Fluvisols and 28.1%, 5.5%, 43.8%, 34.3%, respectively in Anthrosols compared to CF. HPC amendment increased soil bacterial populations by 19 and 8-fold and fungal populations by 1912 and 9-fold in Fluvisols and Anthrosols, respectively. Chinese cabbage yield was positively correlated to TN, NO3−, Pav. and exchangeable Ca and chili pepper yield was positively correlated to TN and NO3−. It is concluded that organic amendments had strong potential to improve soil organic carbon, soil nutrient status, crop yield and microbial activity in Fluvisols and Anthrosols in Tai-Lake region of China. The beneficial results of HPC in soils and crop could reduce the use of mineral fertilizer for the sustainable production of vegetables.

Co‐incorporation of Chinese milk vetch (Astragalus sinicus L.) and rice (Oryza sativa L.) straw minimizes CH4 emissions by changing the methanogenic and methanotrophic communities in a paddy soil

AbstractThe practice of co‐incorporating rice straw and leguminous green manure (such as Chinese milk vetch) into paddy soils has become increasingly popular in the last 10 years, although its effect on soil CH4 emissions and microbial community structure is poorly understood. In this study, data from a 2‐year pot experiment were used to reveal the effects of the co‐incorporation of rice straw and Chinese milk vetch on CH4 emissions and methanogenic and methanotrophic communities in paddy soil. Five treatments were chosen: CK (unamended control), CF (inorganic fertilizer), FM (inorganic fertilizer and Chinese milk vetch, 20 g 10 kg−1 dry soil, 4.5 t ha−1), FR (inorganic fertilizer and rice straw, 20 g 10 kg−1 dry soil, 4.5 t ha−1) and FMR (inorganic fertilizer and Chinese milk vetch and rice straw mixture, 5 + 15 g 10 kg−1 dry soil, 1.125 + 2.375 t ha−1). Overall, the soil CH4 emissions in the 2 years under all residue treatments (104.4–122.8 and 83.3–133.3 g CH4 m−2) were higher than those in CK (57.0 and 20.7 g CH4 m−2) and CF (71.8 and 21.9 g CH4 m−2) treatments. The FMR treatment decreased CH4 emissions when compared with FM and FR, especially in the second year. A higher abundance of methanogens (mcrA gene copies) was found under the plant residue‐treated soils (4.35 × 108 g−1 dry soil on average) and FM increased the abundance of methanotrophs (pmoA gene copies, 2.68 × 106 g−1 dry soil). Application of plant residues changed the methanogenic and methanotrophic community structures in comparison with CF (e.g., markedly increased the populations of Methanobacteriales and Methylomonas and suppressed Methanomicrobiales and Methylobacter populations). Methane emissions were significantly and positively related to the mcrA and pmoA gene copy numbers, as well as the mcrA/pmoA ratio. The partial least squares path model (PLS‐PM) indicated that the rice plant biomass (path coefficient = 0.64), the abundance of methanogens (path coefficient = 0.57) and the community structure of methanotrophs (path coefficient = −0.59) were determinants of CH4 emissions. Among the three residue‐treated soils, FMR showed the lowest CH4 emissions and was associated with a slight decrease in the mcrA/pmoA ratio and a significant increase in the Type I/Type II methanotrophs ratio. Thus, we recommend the co‐incorporation of Chinese milk vetch and rice straw as a sustainable fertilization pattern to improve the growth of rice and minimize CH4 emissions.Highlights Residue application improves rice productivity (except for FR), soil fertility and CH4 emissions. Co‐incorporation of MV and RS reduces CH4 emissions in comparison with pure MV or RS addition. Residue application changes the community structure of methanogens and methanotrophs. The methanogenic abundance and the methanotrophic community structure determine the CH4 emissions.

Trophoblast toxicity of the neonicotinoid insecticide acetamiprid and an acetamiprid-based formulation

The neonicotinoid (Neo) insecticide family is a relatively new class of pesticides of growing use. There is an increasing concern that human exposure to environmental pollutants in utero may be associated with diseases in adulthood. A functional placenta and trophoblasts are a requisite for a healthy pregnancy. The aim of this study was to investigate whether the Neo Acetamiprid (Ace) and one of its commercial formulations (Ace CF) display toxic features to a human first trimester trophoblast cell line. HTR-8/SVneo cells were cultured in the presence of Ace or Ace CF (0.1–100 μM) for 4 and 24 h, and changes in cell viability, reactive oxygen species, antioxidant system and macromolecule damage levels were evaluated.Ace and Ace CF are cytotoxic for HTR-8/SVneo trophoblasts. Cell viability loss and oxidative imbalance were triggered by Ace and Ace CF treatments. Impact in the antioxidant enzymes catalase, superoxide dismutase and gluthatione S-transferase activities were observed after 24 h exposure to Ace CF. Moreover, Ace CF caused oxidative damage in proteins, lipids and DNA, whereas Ace only damaged proteins. To test oxidative stress as a toxicity mechanism, cells were pre-incubated with the antioxidant N-acetyl-l-cysteine (NAC), prior Neo treatment. NAC protected trophoblasts from cell death and prevented oxidative damage.Results demonstrate that Ace (as active principle or CF) is cytotoxic for human trophoblasts, and oxidative stress is a toxicity mechanism. Ace CF exhibited a more toxic effect than the active principle, in an identical exposure scenario.

Quantifying soil N pools and N2O emissions after application of chemical fertilizer and straw to a typical chernozem soil

An incubation experiment with equivalent N rates was conducted for 56 days using a typical black soil amended with chemical fertilizer with or without straw amendment using a 15N cross-labeling technique. Compared with the chemical fertilizer treatment (15NCF), chemical fertilizer combined with straw treatment (CF + S) showed a significantly higher (P < 0.05) contribution from applied N to microbial biomass N (BN) in the first 14 days and to particulate organic N (PON) and mineral-associated total N (MON) throughout the incubation. Straw application in the CF + S treatment significantly (P < 0.05) decreased the recovery of chemical fertilizer N as soil inorganic N except at day 3 but increased the recovery of chemical fertilizer N as BN before day 14 and as PON and MON from day 14 to the end of the incubation period. At the end of the incubation period, the total N2O-N emissions in the CF + S treatment increased significantly (P < 0.05) compared with the CF treatment, and the increase in N2O-N emissions was 73% from chemical fertilizer and 27% from straw N individually. Our results suggest that the combined application of chemical fertilizer and straw increased soil fertility together with an increase in N2O emissions in the typical black soil and the N2O emissions from straw cannot be ignored.

Reduced Cd, Pb, and As accumulation in rice (Oryza sativa L.) by a combined amendment of calcium sulfate and ferric oxide.

A combined amendment (CF) consisting of 90% calcium sulfate (CaSO4) and 10% ferric oxide (Fe2O3) was used to investigate the feasibility, active principles, and possible mechanisms of the immobilization of heavy metals in paddy soil. A soil incubation experiment, two consecutive pot trials, and a field experiment were conducted to evaluate the effectiveness and persistence of CF on metal(loid) immobilization. Soil incubation experiment results indicated that the application of CF significantly decreased the concentrations of cadmium (Cd), lead (Pb), and arsenic (As) in soil solution. CF treatments simultaneously reduced the accumulation of Cd, Pb, and As in two consecutive pot trials. The total Cd, Pb, and As concentrations in the rice grains were respectively 0.02, 2.08, and 0.62 mg kg-1 in the control treatment in the second year, which exceeded the safety limits of contaminants in food products in China. However, a high amount of CF amendment (CF-H, 0.3%) effectively decreased Cd, Pb, and As by 75.0%, 75.5%, and 46.8%, respectively. Further, with the CF amendment, the bioavailable Cd and Pb in the soil and the accumulation of Cd, Pb, and As in rice grain in the field experiment were also significantly decreased. The concentrations of Cd, Pb, and As in grains were respectively 0.02, 0.03, and 0.39 mg kg-1 in the control treatment in the field experiment, which decreased to 0.01, 0.01, and 0.22 mg kg-1 with CF addition, suggesting that grains produced in the field could pose less health risk. In conclusion, these results implied that CF was an effective and persistent combined amendment to immobilize heavy metals in soil and thereby can reduce the exposure risk of metal(loid)s associated with rice consumption.

Effects of application rates of poly-γ-glutamic acid on vegetable growth and soil bacterial community structure

In this study, we investigated the effect of high-molecular-weight γ-PGA (over 4000 kDa) produced by Bacillus sp. A-5 on Chinese cabbage (Brassica rapa L. ssp. chinensis L.) productivity, apparent fertilizer utilization efficiencies, and soil bacterial community structure. Compared to CF treatment, γ-PGA application at low rates (P0 and P1) decreased vegetable yield by 14.29% and 17.30%, respectively; however, P2, P3, and F2 (moderate and high doses of γ-PGA application) offset the chemical fertilizer reduction and thereby increased the apparent utilization efficiencies by 27.82–52.27% for N, 17.05–64.59% for P, and 32.73–41.43% for K. With reduced fertilizer application, the P2, P3, and F2 treatments increased soil bacterial community diversity, richness, and evenness; in contrast, the P0 and P1 treatments decreased these variables. In conclusion, γ-PGA can enhance the apparent fertilizer utilization efficiencies and increase the relative abundances of potential plant-growth-promoting bacteria in soil in a concentration-dependent manner, thereby improving Chinese cabbage yield.

Supplementing calcium salts of soybean oil to beef steers early in life to enhance carcass development and quality1.

This study evaluated the effects of supplementing Ca salts of soybean oil (CSSO) to beef steers at 2 mo of age via creep-feeding, and/or during a 40-d preconditioning period on performance and carcass development responses. A total of 64 steers were enrolled in this study over 2 yr (32 steers per year), with 4 periods each year: creep-feeding (CF; day 0 to 60), preweaning (day 61 to weaning on day 124 and 127 of year 1 and 2, respectively), preconditioning (PC; day 132 to 172 in year 1 and day 135 to 175 of year 2), and feedlot (feedlot arrival to slaughter, day 173 to 378 in year 1 and day 176 to 385 in year 2). On day 0 steers were ranked by body weight (BW) and age (114 ± 4 kg of BW; 66.1 ± 0.9 d of age) and allocated to 1 of 16 pens. Pens were randomly assigned to receive CSSO during CF (80 g/d per steer) and/or PC (150 g/d per steer) in a 2 × 2 factorial arrangement of treatments. During CF and PC, nonsupplemented steers (CON) were provided an isolipidic prilled saturated fat supplement. Steer BW was recorded on day 0, 60, at weaning, and prior to feedlot shipping. Carcass traits were recorded upon slaughter. On day 0, 60, at weaning, prior to feedlot shipping, and during the feedlot period, blood samples were collected and longissimus muscle (LM) biopsies were collected. On day 60, steers that received CSSO during CF had greater (P < 0.01) plasma concentrations of linoleic and ω-6 compared with CON (CF treatment × day; P ≤ 0.05). Steers that received CSSO during PC had greater (P < 0.01) plasma concentrations of linoleic, ω-6, and total fatty acids compared with CON at feedlot shipping (PC treatment × day; P ≤ 0.05). A PC treatment × day interaction was also detected (P = 0.04) for mRNA expression of peroxisome proliferator-activated receptor gamma (PPAR-γ), which was greater (P = 0.04) at feedlot shipping for steers receiving CSSO during PC. Interactions between CF treatment × day were detected (P ≤ 0.01) for mRNA expression of adipocyte fatty acid-binding protein, fatty acid synthase, PPAR-γ, and stearoyl-CoA desaturase, which were greater (P ≤ 0.02) in the feedlot in steers receiving CSSO during CF. No treatment differences were detected for (P ≥ 0.18) performance or carcass traits, including marbling and backfat thickness. Results from this study suggest that supplementing CSSO to suckled beef steers via creep-feeding upregulated mRNA expression of the adipogenic genes investigated herein later in life. These outcomes, however, were not translated into improved carcass quality.

Soil respiration and organic matter decomposition dynamics respond to legacy fertilizer and weed control treatments in loblolly pine stands

Most studies examining how forest soil carbon (C) cycling responds to silvicultural treatments are restricted to a single rotation, with the legacy effects of past management practices being relatively unstudied. Here, we examined soil respiration and organic matter decomposition dynamics (important proxies for C dynamics), climate, and nutrient cycling in a second rotation, 2-year-old loblolly pine (Pinus taeda L.) plantation in north Florida. Carryover (C-) effects of the previous rotation's control (CC), fertilizer (CF), weed control (CW), and combined fertilizer and weed control (CFW) treatments were examined for residual effects on soil respiration (Rs), heterotrophic respiration (Rh), and substrate decomposition potential. Repeated measurements were made over 13 months. The mean Rs for both the CF (4.56 μmol CO2 m−2 s−1) and CFW (4.49 μmol CO2 m−2 s−1) treatments were increased by 29% and 27%, respectively, compared to the CC (3.53 μmol CO2 m−2 s−1) treatment. The Rh in the CW (2.97 μmol CO2 m−2 s−1) was significantly lower compared to the CF (4.02 μmol CO2 m−2 s−1) and CFW (3.66 μmol CO2 m−2 s−1) treatments, despite having warmer soil temperatures than the CF treatment, and no differences in soil moisture contents. Soil temperature and Mehlich III soil extractable manganese (Mn) concentrations (0–10 cm) were the only variables that explained variation in Rh. Decomposition rates for a common substrate were also lower in the CW compared to the CF, treatment (p = 0.027), potentially because the removal of understory plants in the CW treatment affected both microclimate and Mn cycling compared to the CF treatment where understory plants were retained and micronutrients were added as fertilizers. Overall, forest management affected organic matter cycling after replanting and 12 years after the last treatment in the previous rotation, suggesting that long-term studies are needed to understand the effects of silvicultural practices on ecosystem C cycling.

First clinical trials of novel ENaC targeting therapy, SPX-101, in healthy volunteers and adults with cystic fibrosis

BackgroundENaC inhibition has been investigated as a CF treatment; however, small molecule inhibitors of ENaC lack efficacy and/or have shown dose-limiting hyperkalemia. SPX-101 is a novel, investigational small peptide (SPLUNC1 mimetic) that regulates ENaC density with the potential for efficacy without systemic effects. MethodsTwo trials are presented: The first was a Phase 1, 2-part, randomized, double-blind, placebo-controlled, ascending-dose study of nebulized SPX-101 in healthy adults. Part 1 evaluated 4 single doses of SPX-101 ranging from 20 to 240 mg. Part 2 evaluated a 14-day regimen of SPX-101 at 4 doses of SPX-101 ranging from 10 to 120 mg BID. Pharmacokinetics, adverse events, spirometry, vital signs, electrocardiograms, pulse oximetry, and clinical laboratory values were assessed. The second trial was a tolerability-confirming, Phase 1b, open-label study conducted in 5 adult subjects with CF. Ascending doses of SPX-101 inhalation solution (10 mg–120 mg BID) were administered for 7 days. Safety was assessed as described above. ResultsAll 64 healthy volunteers (32 in each Part) completed the single and multiple dose study. SPX-101 was well tolerated with little/no systemic exposure and with no hyperkalemia. Adverse events were generally mild with reported respiratory events associated with the purported pharmacological activity of SPX-101. Tolerability of SPX-101 was similarly observed in adults with CF; all 5 subjects treated with SPX-101 completed the study. ConclusionsSPX-101 was well-tolerated across a range of doses and had little/no systemic exposure in healthy adults and adults with CF, thus supporting further study in patients with CF. Clinicaltrial.gov registrationNCT03056989.

Effects of water management and cultivar on carbon dynamics, plant productivity and biomass allocation in European rice systems

Water saving techniques, such as alternate wetting and drying (AWD), are becoming a necessity in modern rice farming because of climate change mitigation and growing water use scarcity. Reducing water can vastly reduce methane (CH4) emissions; however, this net climate benefit may be offset by enhanced carbon dioxide (CO2) emissions from soil. The main aims of this study were: to determine the effects of AWD on yield and ecosystem C dynamics, and to establish the underlying mechanistic basis for observed trends in net ecosystem C gain or loss in an Italian rice paddy. We investigated the effects of conventional water management (i.e. conventionally flooded paddy; CF) and AWD on biomass accumulation (aboveground, belowground, grain), key ecosystem C fluxes (net ecosystem exchange (NEE), net primary productivity (NPP), gross primary productivity (GPP), ecosystem respiration (ER), autotrophic respiration (RA), heterotrophic respiration (RH)), and soil organic matter (SOM) decay for four common commercial European rice cultivars. The most significant finding was that neither treatment nor cultivar affected NEE, GPP, ER or SOM decomposition. RA was the dominant contributor to ER for both CF and AWD treatments. Cultivar and treatment affected the total biomass of the rice plants; specifically, with greater root production in CF compared to AWD. Importantly, there was no effect of treatment on the overall yield for any cultivar. Possibly, the wetting-drying cycles may have been insufficient to allow substantial soil C metabolism or there was a lack of labile substrate in the soil. These results imply that AWD systems may not be at risk of enhancing soil C loss, making it a viable solution for climate change mitigation and water conservation. Although more studies are needed, the initial outlook for AWD in Europe is positive; with no net loss of soil C from SOM decomposition, whilst also maintaining yield.

Sustained productivity of intensively managed loblolly pine plantations: Persistence of fertilization and weed control effects across rotations

Two randomized complete block design experiments were used to study the effects of fertilization and weed control treatments on the productivity of second rotation loblolly pine (Pinus taeda L.) plantations growing on poorly-drained Spodosols in north Florida. One experiment (actively managed retreated) received similar treatments as in the first rotation (Control, C; Fertilizer, F; Fertilizer + weed control, FW; Weed control, W), and the second was left untreated in the second rotation [untreated carryover (C-): CC, CF, CFW, and CW]. Comparisons of total height and current annual increment across rotations indicated that the second-rotation stands were more productive than the first-rotation. In the current rotation of the untreated carryover experiment, treatments that received fertilizer in the first rotation (CF and CFW) accumulated significantly more aboveground biomass compared to the CC treatment [i.e. CF (63 Mg ha−1) = CFW (60 Mg ha−1) > CC (40 Mg ha−1)]. From the third to the fourth year, biomass accumulation in CF exceeded CFW, but by the fifth to the seventh years the two treatments were similar; a change that likely occurred because of root development into the lower solum for the CFW or increased understory competition in the CF treatment. In the actively managed retreated experiment, cumulative total aboveground biomass accumulation followed the trend: FW (90.6 Mg ha−1) > F (71.8 Mg ha−1) > W (55.1 Mg ha−1) > C (31.8 Mg ha−1). Comparison of upper quartile height gains due to fertilization between the first- and second- rotation experiments suggested that fertilizer added in the second rotation only provided growth gains after the fourth year. Our results suggest that management practices enhanced levels of productivity across treatments and rotations with some adjustment caused by carryover effects from past fertilization and weed control treatments.