Greenhouse gas reduction of co-benefit-type wastewater treatment system for fish-processing industry: A real-scale case study in Indonesia

This study examined the application of co-benefit-type wastewater treatment technology in the fish-processing industry. Given that there was a dearth of information on fish-processing industrial wastewater in Indonesia, site surveys were conducted. For the entire fish-processing industry throughout the country, the dissemination rate of wastewater treatment facilities was less than 50%. Using a co-benefit approach, a real-scale swim-bed technology (SBT) and a system combining an anaerobic baffled reactor (ABR) with SBT (ABR–SBT) were installed in a fishmeal processing factory in Bali, Indonesia, and the wastewater system process performance was evaluated. In a business-as-usual scenario, the estimated chemical oxygen demand load and greenhouse gas (GHG) emissions from wastewater from the Indonesian fish-processing industry were 33 000 tons per year and 220 000 tons of equivalent CO_(2) per year, respectively. On the other hand, the GHG emissions in the co-benefit scenarios of the SBT system and ABR–SBT system were 98 149 and 26 720 tons per year, respectively. Therefore, introducing co-benefit-type wastewater treatment to Indonesia’s fish-processing industry would significantly reduce pollution loads and GHG emissions.

Exploration of Methane Mitigation Efficacy Using Asparagopsis-Derived Bioactives Stabilized in Edible Oil Compared to Freeze-Dried Asparagopsis in Vitro

Asparagopsis oil products are of interest due to the stabilizing effects of the Asparagopsis-derived antimethanogenic bioactive compound bromoform (CHBr3). The objective of this in vitro series is to characterize antimethanogenic efficacy of freeze-dried Asparagopsis (FD-Asp) and Asparagopsis oil (Asp-Oil) and compare relative antimethanogenic response over time at multiple levels of CHBr3 delivery. Relative methane (CH4) emissions (mL/g) are based on in vitro apparent feed digested dry matter (IVDDM) after 24, 48, and 72 h of fermentation. CHBr3 contained in FD-Asp was included at 95, 191, and 286 mg/kg, and CHBr3 contained in Asp-Oil was included at 78, 117, and 175 mg/kg, to produce the Low, Mid, and High inclusions, respectively. Low FD-Asp had no significant impact on CH4 emissions, Mid FD-Asp demonstrated 91%, 44%, and 37% reductions, and the High FD-Asp demonstrated complete inhibition of CH4, after 24, 48, and 72 h of fermentation, respectively. Comparatively, Low Asp-Oil demonstrated a 46%, 28%, and 18% CH4 reduction, Mid Asp-Oil resulted in 99%, 92%, and 73% reductions, and the High Asp-Oil demonstrated complete inhibition of CH4 after 24, 48, and 72 h of fermentation, respectively. IVDDM and total volatile fatty acid (tVFA) production were not changed by the inclusion of FD-Asp and Asp-Oil. The results from this study show that Asparagopsis is not only a compelling CH4 mitigating feed supplement but is also able to be delivered in edible oil forms which will strengthen its applicability to on-farm use. This study is promising for the utility of Asp-Oil, and in vivo trials are essential to demonstrate the extent of efficacy of Asp-Oil in ruminant animals because FD-Asp has consistently demonstrated greater antimethanogenic efficacy in vivo compared to in vitro.

Agolin Ruminant®, an Essential Oil Blend, Increases Energy-Corrected Milk and Feed Efficiency in a High Component Dairy Herd

Agolin® Ruminant (Agolin) is a blend of essential oils developed to improve feed efficiency while at the same time reducing rumen enteric methane production. Studies have shown that the product improves lactational performance, but the range of results has been varied. This experiment evaluated the effects of the feed additive Agolinon milk production in a high-component (fat and protein) dairy herd when provided for an extended time. The experiment was conducted at a large commercial dairy in the Pacific Northwest, USA. Eight pens of cows (350 to 500 cows/pen) were blocked by production, and pens within blocks were randomly assigned to treatment. All pens received a common total mixed ration. Treatment consisted of providing 1 g/cow/day of Agolin to the test group. A 4-week adaptation period was followed by an 11-week study period. Milk production and milk composition were determined by cow by averaging daily performance for the one-week period before the start of the trial (covariate period) and the last week of each of the two test periods. Feed intakes were determined by pen at the same time. Milk yield was 1.11 kg/cow/day greater (P < 0.001) at the midpoint and 1.48 kg/cow/day greater (P < 0.001) at the end of the test period for cows receiving the feed additive. Similarly, protein yields were 0.03 (P < 0.001) and 0.07 kg/cow/day greater (P < 0.001) at the midpoint and end of the feeding period. Milk fat yield was not different (P = 0.854) between treatment groups at the midpoint of the trial but increased with treatment (P = 0.002) by the end of the trial. Energy-corrected milk/feed ratio, based on pen parameters, was significantly altered by treatment at the final test period (1.48 vs. 1.64 kg/kg for control and test treatments, respectively).

Challenges to increasing the soil carbon pool of agro-ecosystems in China

Climate change will place agro-ecological systems and food security at serious risk. At the 21 st Conference of the Parties（COP21） in Paris in December of 2015, parties to the United Nations Framework Convention on Climate Change（UNFCCC） reached a historic agreement（Paris Agreement） to combat climate change and to accelerate and intensify the actions and investments needed for a sustainable low carbon future. An initiative named the "4‰ initiative: Soils for food security and climate" was proposed by the French Minister of Agriculture, and this initiative was launched officially at the COP21 and adopted by many global organizations. The aim of this initiative was to increase carbon sequestration in soil to mitigate fossil fuel combustion emissions of greenhouse gasses. The present study found that China has high CO;emissions but a low soil carbon pool, and indicates that 4‰ increments of the soil carbon pool will not be sufficient to offset national CO;emissions. The current soil carbon sequestration rate would also not reach the mean level requested by the initiative. Therefore, China faces big challenges to achieve this initiative. An integrated use of straw technology may be used more widely to improve carbon sequestration, and other opportunities include improved fertilizer use efficiency and greenhouse gas mitigation through the waste management project under construction in China. This paper suggests that China may put forward the biomass treatment centered high yield and fertilizer-carbon sequestration project to enhance resilience of agro-ecosystems to climate change.

Changing the Proportions of Grass and Grain in Feed Substrate Impacts the Efficacy of <i>Asparagopsis taxiformis</i>to Inhibit Methane Production <i>in Vitro</i>

Benefits of the red seaweed Asparagopsis taxiformis as an ingredient to manage methane (CH4) emissions from the red meat and dairy industries continue to evolve. Asparagopsis has been demonstrated to eliminate enteric CH4 emissions in vitro and reduce it greater than 80% in animals. Variability in animal studies is suspected to be associated with variable inclusion and proportions of grass and grain in the diet. This in vitro study aimed to elucidate effects of gradient grass to grain proportions in the fermentation using five steps from 100% Rhodes grass (RG) to 100% barley grain (BG). Gradient inclusion of Asparagopsis was in six steps of Control with no inclusion (C), Low (L), Low-Medium (LM), Medium (M), Medium-High (MH), and High (H) levels tested in three fermentation durations (24 h, 48 h, 72 h). There was significant effect of RG/BG and inclusion of Asparagopsis such that CH4 production decreased with increasing Asparagopsis independent of RG/BG;however, there was enhanced reduction at greater proportions of BG. Thus, the level of Asparagopsis required to completely inhibit CH4 production in vitro was decreased with decreasing RG/BG. Increasing the duration of fermentation had greatest effect on CH4 at C, L, and LM levels of Asparagopsis independent of RG/BG, although magnitude of CH4 production was greater for higher proportions of BG for the C and L levels. Digestibility of in vitro substrate increased with fermentation duration and increasing BG;however, there was no change associated with inclusion levels of Asparagopsis. Increases in total volatile fatty acids (tVFA) were observed with increased fermentation duration and concomitant with increasing substrate digestion. Increasing proportions of BG induced increase in tVFA. In contrast, and independent of changes in substrate, increasing inclusion of Asparagopsis had little effect on tVFA. The acetic and propionic acid ratio (AA:PA) decreased with decreasing RG/BG and increasing Asparagopsis. This pattern was most pronounced with 100% BG and MH-H Asparagopsis levels. Compared to control, there was decrease in the AA:PA ratio with addition of even L levels of Asparagopsis and with L compared to LM inclusion levels. Increasing levels of BG and Asparagopsis resulted in significant decreases in AA:PA ratios and CH4 production. This study has confirmed that gradient levels (ratio) of grass and grain in a feed mix impact the antimethanogenic efficacy of Asparagopsis during in vitro fermentation with rumen fluid.

Evaluation of Agolin® Ruminant, an Essential Oil Blend, as a Feed Additive for Cows at Two Levels of Production

Agolin® Ruminant (Agolin) is a commercially available blend of essential oils which has been demonstrated to reduce greenhouse gas emissions in dairy cows and improve energy corrected milk and feed efficiency. Further trials are needed with large numbers of cows to confirm the magnitude of effect of this feed additive on milk production under differing feeding conditions and stages of lactation. Information that can be quantified from newer on-farm systems of measurement is likewise needed. This study was conducted to determine the effects of this additive on high producing (48 kg of milk/day average) just past peak lactation and medium producing dairy cows (43 kg of milk/day average) further along in lactation under commercial conditions that would typically occur in the Pacific Northwest USA. Four pens of approximately 400 Holstein cows/pen (two high producing pens and two medium producing pens) were available for this side-by side study. Performance results were determined using data derived from a subscription standardized monitoring system (High Desert Dairy Laboratory, Inc, Nampa, ID, USA) that provided results for milk yield, fat percentage and protein percentage. As well daily in-stall electronic monitoring of milk only was available. All pens received a common total mixed ration typical of rations fed in the Pacific Northwest, USA. The Agolin feed additive was dispensed through the bulk mineral supply with control cows receiving the normal minerals and the treatment cows receiving the normal minerals plus Agolin. The trial began on August 24, 2021, with treatment cows provided with 1 g/head/day for the duration of the 8-week long study. Dry matter intakes were determined daily for the week before the trial was conducted and the last week of the trial. Treatment results were compared using a general linear model that considered pretrial milk, fat yield and protein yield, days in milk and lactation number. There were 678 high producing cows available for the duration of the study. Based on the standardized testing results, milk yield was greater (1.12 kg/cow/day;P < 0.05) for the cows in the treatment group. There was a tendency for fat corrected milk (FCM) and energy corrected milk (ECM) to be greater for the cows receiving the Agolin feed additive (0.96 and 0.86 kg/cow/day for FCM and ECM respectively, P < 0.10). There were 646 medium producing cows that participated in the trial. There was no treatment effect upon milk production (P = 0.27). There was a significant (P < 0.05) increase in milk fat yield and no change (P = 0.33) in protein yield for the treatment cows in this test group, resulting in greater FCM and ECM (1.12 and 0.95 kg/cow/day;P < 0.05). Daily milk monitoring resulted in a reduced decline in milk yield from the week before to the final week of the trial revealing greater persistency of milk for Agolin-fed cows in both high and medium production pens (1.58 and 2.13 kg/cow/day;P < 0.01). Likewise, overall feed efficiency was improved by 5.3% (P < 0.05) with the test product.

Profit Analysis by Soil Carbon Sequestration with Different Composts and Cooperated with Biochar during Corn (Zea mays) Cultivation Periods in Sandy Loam Soil

Despite the ability of biochar to enhance soil fertility and to sequester soil carbon, its potential reduction of green house gas emissions and profit analysis with different organic composts and cooperated with biochar for crop cultivation have been a few evaluated. This study was conducted to estimate their greenhouse gas emission reduction and profit analysis by soil carbon sequestration with different organic composts and cooperated with biochar application during corn cultivation periods. For the experiment, the treatments were consisted of aerobic digestate of swine wastes (AD), pig compost as the control (PC), cow compost (CC) and pig compost cooperated with 1% biochar (PC + 1% biochar). The soil texture used in this study was sandy loam, and application rates of chemical fertilizer were 190-39-221 kg·ha-1 (N-P2O5-K2O) as recommended amount after soil test. The soil samples were periodically taken at every 15 day intervals during the experimental periods. It was observed that soil carbon sequestration by AD, CC and PC + 1% biochar application was estimated to be 429 kg·ha-1, 2366 kg·ha-1, and 3978 kg·ha-1, and their CO2-e emission reductions were estimated to be 0.16 tones for AD, 0.87 tones for CC, and 14.58 tones for PC + 1% biochar per hectar for corn cultivation periods. Their profits were estimated at $14.58 for lowest and $451.90 for highest. In Korea Climate Exchange, it was estimated to be $115.20 per hectar of corn cultivation with PC + 1% biochar. So, the price of CO2 per hectar for corn cultivation with PC + 1% biochar was high at 16.8 times relative to cow compost treatment only. For the plant growth response, it was observed that plant height and fresh ear yield were not significantly different among the treatments. Therefore, these experimental results might be fundamental data for assuming a carbon trading mechanism exists for biochar soil application in agricultural practices.

Effects of the nitrification inhibitor nitrapyrin and the plant growth regulator gibberellic acid on yield-scale nitrous oxide emission in maize fields under hot climatic conditions

Nitrification inhibitors are widely used in agriculture to mitigate nitrous oxide(N_(2)O)emission and increase crop yield.However,no concrete information on their mitigation of N_(2)O emission is available under soil and environmental conditions as in Pakistan.A field experiment was established using a silt clay loam soil from Peshawar,Pakistan,to study the effect of urea applied in combination with a nitrification inhibitor,nitrapyrin(2-chloro-6-tri-chloromethyl pyridine),and/or a plant growth regulator,gibberellic acid(GA_3),on N_(2)O emission and the nitrogen(N)uptake efficiency of maize.The experimental design was a randomized complete block with five treatments in four replicates:control with no N(CK),urea(200 kg N ha^(-1))alone,urea in combination with nitrapyrin(700 g ha^(-1)),urea in combination with GA_3(60 g ha^(-1)),and urea in combination with nitrapyrin and GA_3.The N_(2)O emission,yield,N response efficiency,and total N uptake were measured during the experimental period.The treatment with urea and nitrapyrin reduced total N_(2)O emission by 39%–43%and decreased yield-scaled N_(2)O emission by 47%–52%,relative to the treatment with urea alone.The maize plant biomass,grain yield,and total N uptake increased significantly by 23%,17%,and 15%,respectively,in the treatment with urea and nitrapyrin,relative to the treatment with urea alone,which was possibly due to N saving,lower N loss,and increased N uptake in the form of ammonium;they were further enhanced in the treatment with urea,nitrapyrin,and GA_3 by 27%,36%,and 25%,respectively,probably because of the stimulating effect of GA_3 on plant growth and development and the reduction in biotic and abiotic stresses.These results suggest that applying urea in combination with nitrapyrin and GA_3 has the potential to mitigate N_(2)O emission,improve N response efficiency,and increase maize yield.