Manure application has an effect on the carbon budget of a managed grassland in southern Hokkaido,Japan

Abstract

The carbon (C) budget of managed grassland in a cool-temperate region of Japan was estimated using a combination of eddy covariance and the biometric method for five years, to evaluate the effect of manure application. Chemical fertilizer was applied to the fertilizer (F) plot at a rate of 79 ± 20 kg N ha^?1 yr^?1. In the manure (M) plot, dairy cattle manure was applied at a rate of 10 Mg fresh matter ha^?1 yr^?1 (1923 ± 407 kg C ha^?1 yr^?1, 159 ± 68 kg N ha^?1 yr^?1). There was no significant difference in seasonal gross primary production (GPP) and harvest between the treatment plots, indicating that both fertilizer and manure can increase the biomass production. Annual net ecosystem production (NEP) and ecosystem respiration (RE) was significantly different between the treatment plots. The difference in RE, and between M and F plots approximates heterotrophic respiration of manure (RHm), which ranged from 0.9 to 1.3 Mg C ha^?1 yr^?1. Average annual RHm was 1.1 ± 0.4 Mg C ha^?1 yr^?1, and accounted for 56% of the total amount of applied manure C. The annual net biome production (NBP) in the M plot (from 0.0 to 1.5 Mg C ha^?1 yr^?1) was significantly higher than in the F plot (?1.4 to 0.5 Mg C ha^?1 yr^?1). The long-term effect of manure application combined with chemical fertilizer did not reduce grass production compared with chemical fertilizer only; however, manure application decreased the NEP throughout manure decomposition, and long-term manure application enhanced the NBP.     

Nitrogen accumulation in soybean [Glycine max (L.) Merr.] is increased by manure compost application in drained paddy fields as a result of increased soil nitrogen mineralization

The application of manure compost is an effective way to increase soybean [Glycine max (L.) Merr.] yield and nitrogen (N) fertility in drained paddy fields. We investigated changes in soil N mineralization during soybean cultivation using reaction kinetics analysis to determine the contribution of increased N mineralization after manure compost application (at a rate of 0 to 6?kg?m^?2) on N accumulation and seed yield of soybean under drained paddy field conditions. The seed yield and N accumulation decreased markedly in the second and third year of the experiment, but soil N mineralization increased in both years. No decrease in soil N mineralization occurred even after two soybean crops. Soil N availability was not the main cause of decreased soybean yield in the second and third years. The differences in plant aboveground N content between plots with and without manure compost was similar to the increase in N mineralization caused by manure compost application in the second and third years. The application of 6?kg?m^?2 of manure compost increased the amount of ureide-N and nitrate-N in soybean in the third year. Our results suggest that manure compost application increases soil N mineralization and soybean N₂ fixation, resulting in increased N accumulation and seed yield. However, the soybean yield remained less than 300?g?m^?2 in the second and third years (i.e., below the yield in the first year) at all levels of manure compost application due to the remarkable decrease of N accumulation in the second and the third crops.     

Enrichment of natural 15N abundance in frankia-infected nodules

Abstract

The enrichment of ¹⁵N in the nodules of some N₂-fixing leguminous plants is an interesting finding (Shearer et al. 1982). The extent of ¹⁵N enrichment differed depending on the plant species (Shearer et al. 1982; Yoneyama 1987) and bacterial strains (Steele et al. 1983), and in soybeans it was apparently related to the nitrogen fixation efficiency (Shearer et al. 1984)     

Measuring farmers’ preferences for weather index insurance in the Ayeyarwady Delta,Myanmar: a discrete choice experiment approach

Paddy and Water Environment - This study examines farmers’ preferences for weather index insurance (WII) in the Ayeyarwady Delta, Myanmar, using discrete choice experiments. It employs data...     

Fixed-fixed flexural vibration testing method of beams for timber guardrails

Resonance frequencies of beams with various types of end supports were examined for flexural vibration. Rectangular beams with dimensions of 300 (L) × 25 (R) × 5 or 10mm (T) were used as the test specimens. Various compressing stresses were applied to the parts around both ends of a test beam and flexural vibration tests were conducted. The measured resonance frequency started to increase from the resonance frequency of a beam with simply supported ends and was stable around the resonance frequency of a beam with fixed ends as the compressing stress increased. The stable resonance frequency was lower than the theoretical value because perfect fixation of a beam to a post was difficult. From these results, the temporal change in resonance frequency itself, rather than the stable resonance frequency, is effective to examine whether a beam has enough strength as a guardrail.     

Coniferyl aldehyde dimers in dehydrogenative polymerization: model of abnormal lignin formation in cinnamyl alcohol dehydrogenase-deficient plants

The enzymatically dehydrogenative polymerization of coniferyl aldehyde and coniferyl alcohol was studied to understand lignins in cinnamyl alcohol dehydrogenase (CAD)-downregulated plants. The sample dimers were prepared by polymerization under three reaction systems (coniferyl alcohol, coniferyl aldehyde, and their combination) with horseradish peroxidase/H₂O₂ under the conditions of limited reaction time. In addition, the residual amount of substrate in each reaction was determined at specified time intervals. In the reaction system of coniferyl aldehyde, the 5-5-type dimer was formed in preference to- and-5 dimers; in the reaction system of coniferyl alcohol the-5 dimer was preferentially formed. Furthermore, it was revealed when quantifying dimers among reaction systems that the total dimer formation capability of coniferyl alcohol clearly surpassed that of coniferyl aldehyde. However, the dimers cross-coupled with coniferyl alcohol and coniferyl aldehyde were formed in amounts not accounted for by the difference seen in dimer formation abilities with the two substrates.Part of this paper was presented at the 49th Annual Meeting of the Japan Wood Research Society, Tokyo, April 1999     

Cost, energy and carbon dioxide (CO2) effectiveness of a harvesting and transporting system for residual forest biomass

The purpose of this study is to examine the feasibility of a system to harvest logging residues (or slashes) as a new resource for energy in Japan. A harvesting and transporting system for residual forest biomass was constructed with reference to some European countries where the utilization of bioenergy is making steady progress and examined on the basis of field experiments in Japanese forestry. The feasibility of the system is discussed from the standpoints of cost and energy, and the system is compared with those of the European countries. With respect to the system proposed in this study, it is desirable that the process of chipper comminuting is incorporated into the system as early as possible, considering the trends of harvesting cost and fuel consumption per unit weight of residual forest biomass. Such a system is not particularly feasible in Japan from the standpoint of the harvesting cost per MWh of bioenergy. However, no specific problems are found from the point of view of the energy input rate, and it is clarified that it is possible for Japan to reduce domestic carbon dioxide emissions by utilizing biomass as an energy resource. A comparison with the European countries and a preliminary sensitivity analysis of the system demonstrate that the technical development to reduce the harvesting cost,e.g., improving the forwarding and transporting efficiency, and support from the government are essential for realizing bioenergy utilization in Japan. A part of this paper was orally presented at the 111th Annual Meeting of the Japanese Forestry Society (2000). JSPS Research Fellow. This study was supported in part by a Grant-in-Aid for Scientific Research from the Japan Ministry of Education, Science and Culture (No. 10460061).     

Lignans ofChamaecyparis obtusa

Heartwood ofChamaecyparis obtusa contains significant amounts of a dibenzylbutyrolactone lignan, hinokinin (8). This investigation demonstrated that the contents of 8 and a norlignan, hinokiresinol (12), were higher in the heartwood region than in the sapwood, indicating their nature of being heartwood extractives. Eleven lignans — xanthoxylol (1), 7-oxohinokinin (2), savinin (3), dihydrosesamin (4), isoactifolin (5), sesamin (6), piperitol (7), hinokinin (8), pluviatolide (9), haplomyrfolin (10), and rnatairesinol (11) — were isolated from young shoots ofChamaecyparis obtusa cv. Breviramea. Eight lignans (1, 2, 4, 5, 7, 9,10, and11) were isolated from this plant for the first time. Chiral high-performance liquid Chromatographie analysis showed that8, 9, 10, and11, were found to be levorotatory and optically pure (>99% e.e.). Based on the chemical structures of the isolated lignans, possible biosynthetic pathways of8 are discussed.Parts of this report were presented at the 44th annual meeting of the Japan Wood Research Society, Nara, April 1994; the 46th annual meeting of the Japan Wood Research Society, Kumamoto, April 1996; and the 44th Lignin Symposium, Gifu, October 1999