The paper presents a study on increasing energy independence of a 200 m2 horticultural hothouse, by means of heating it with thermal energy from a TLUD （top-lit-up-draft） gasification procedure of local residual agr...The paper presents a study on increasing energy independence of a 200 m2 horticultural hothouse, by means of heating it with thermal energy from a TLUD （top-lit-up-draft） gasification procedure of local residual agricultural biomass, chopped at 10-50 mm and dried at 10%-15% RH （relative humidity）. It produces an average of 14% higt quality biochar. Hot-air heating system and forced circulation are equipped with two GAZMER 40/150G energetic modules, which are rechargeable, simple, safe, efficient and environmentally friendly. They can gasify chopped or pelletised biomass. To study the microclimate evolution, it was used a complex numerical model for a 200 m2 hothouse for growing vegetables. Simulated experiments were carried out for frosty days and, estimated, for the whole warming period. Each year 13.44 t of biomass are consumed, resulting 1.78 t ofbiochar which, when introduced in soil, produces a -6.2 t/year negative balance of CO2.展开更多
Bamboos are one of the fast-growing and multiple use species in the world, and thus bamboo forests/plantations play an important role in C sequestration at regional and global levels. We studied aboveground litterfall...Bamboos are one of the fast-growing and multiple use species in the world, and thus bamboo forests/plantations play an important role in C sequestration at regional and global levels. We studied aboveground litterfall, litter decomposition and nutrient dynamics for two years in two subtropical bamboo ecosystems in Southwest China so as to test the hypothesis that litter quality determine the rate and nutrient dynamics during decomposition of different litter fractions. Mean annual total aboveground litter production ranged from 494 to 434 g m-2 in two bamboo stands （P stand, dominated by Pleioblastus amarus and H stand, hybrid bamboo dominated by Bambusa pervariabilis x Dendrocalamopsis daii）. Bulk （-80%） of litter production was contributed by leaf litter in two stands followed by twigs and sheathes. Different litter fractions represented considerable variations in the rates of mass loss and nutrient release. Variation of the mass remaining after 2 years of decomposition was significantly explained by initial C/N ratio and initial P concentration. Initial concentrations of N, P, Ca, and Mg explained 57.9%, 95.0%, 99.8% and 98.1%, respectively, of the variations of these elements mass remaining after 2 years of decomposition. The patterns of nutrient dynamics and the final amount remaining were mainly determined by their initial litter substrate quality in tl^ese two subtropical bamboo plantations.展开更多
Crop yields in sandy soils can be increased by addition of clay-rich soil, but little is known about the effect of clay addition on nutrient availability after addition of plant residues with different C/N ratios. A l...Crop yields in sandy soils can be increased by addition of clay-rich soil, but little is known about the effect of clay addition on nutrient availability after addition of plant residues with different C/N ratios. A loamy sandy soil （7% clay） was amended with a clay-rich subsoil （73% clay） at low to high rates to achieve soil mixtures of 12%, 22%, and 30% clay, as compared to a control （sandy soil alone） with no clay addition. The sandy-clay soil mixtures were amended with finely ground plant residues at 10 g kg-l： mature wheat （Triticum aestivum L.） straw with a C/N ratio of 68, mature faba bean （Vicia faba L.） straw with a C/N ratio of 39, or their mixtures with different proportions （0% 100%, weight percentage） of each straw. Soil respiration was measured over days 0-45 and microbial biomass C （MBC）, available N, and pH on days 0, 15, 30, and 45. Cumulative respiration was not clearly related to the C/N ratio of the residues or their mixtures, but C use efficiency （cumulative respiration per unit of MBC on day 15） was greater with faba bean than with wheat and the differences among the residue mixtures were smaller at the highest clay addition rate. The MBC concentration was lowest in sole wheat and higher in residue mixtures with 50% of wheat and faba bean in the mixture or more faba bean. Soil N availability and soil pH were lower for the soil mixtures of 22% and 30% clay compared to the sandy soil alone. It could be concluded that soil cumulative respiration and MBC concentration were mainly influenced by residue addition, whereas available N and pH were influenced by clay addition to the sandy soil studied.展开更多
文摘The paper presents a study on increasing energy independence of a 200 m2 horticultural hothouse, by means of heating it with thermal energy from a TLUD （top-lit-up-draft） gasification procedure of local residual agricultural biomass, chopped at 10-50 mm and dried at 10%-15% RH （relative humidity）. It produces an average of 14% higt quality biochar. Hot-air heating system and forced circulation are equipped with two GAZMER 40/150G energetic modules, which are rechargeable, simple, safe, efficient and environmentally friendly. They can gasify chopped or pelletised biomass. To study the microclimate evolution, it was used a complex numerical model for a 200 m2 hothouse for growing vegetables. Simulated experiments were carried out for frosty days and, estimated, for the whole warming period. Each year 13.44 t of biomass are consumed, resulting 1.78 t ofbiochar which, when introduced in soil, produces a -6.2 t/year negative balance of CO2.
基金Supported by the National Natural Science Foundation,China(No.31300522)the Specialized Research Fund for the Doctoral Program of Higher Education,China(No.20125103120018)+1 种基金the Scientific Research Fund of Sichuan Provincial Education Department,China(No.12ZA118)the National Key Technology R&D Program,China(No.2011BAC09B05)
文摘Bamboos are one of the fast-growing and multiple use species in the world, and thus bamboo forests/plantations play an important role in C sequestration at regional and global levels. We studied aboveground litterfall, litter decomposition and nutrient dynamics for two years in two subtropical bamboo ecosystems in Southwest China so as to test the hypothesis that litter quality determine the rate and nutrient dynamics during decomposition of different litter fractions. Mean annual total aboveground litter production ranged from 494 to 434 g m-2 in two bamboo stands （P stand, dominated by Pleioblastus amarus and H stand, hybrid bamboo dominated by Bambusa pervariabilis x Dendrocalamopsis daii）. Bulk （-80%） of litter production was contributed by leaf litter in two stands followed by twigs and sheathes. Different litter fractions represented considerable variations in the rates of mass loss and nutrient release. Variation of the mass remaining after 2 years of decomposition was significantly explained by initial C/N ratio and initial P concentration. Initial concentrations of N, P, Ca, and Mg explained 57.9%, 95.0%, 99.8% and 98.1%, respectively, of the variations of these elements mass remaining after 2 years of decomposition. The patterns of nutrient dynamics and the final amount remaining were mainly determined by their initial litter substrate quality in tl^ese two subtropical bamboo plantations.
基金supported by a postdoctoral award of Australian Department of Education and Training Endeavour to S. Pal
文摘Crop yields in sandy soils can be increased by addition of clay-rich soil, but little is known about the effect of clay addition on nutrient availability after addition of plant residues with different C/N ratios. A loamy sandy soil （7% clay） was amended with a clay-rich subsoil （73% clay） at low to high rates to achieve soil mixtures of 12%, 22%, and 30% clay, as compared to a control （sandy soil alone） with no clay addition. The sandy-clay soil mixtures were amended with finely ground plant residues at 10 g kg-l： mature wheat （Triticum aestivum L.） straw with a C/N ratio of 68, mature faba bean （Vicia faba L.） straw with a C/N ratio of 39, or their mixtures with different proportions （0% 100%, weight percentage） of each straw. Soil respiration was measured over days 0-45 and microbial biomass C （MBC）, available N, and pH on days 0, 15, 30, and 45. Cumulative respiration was not clearly related to the C/N ratio of the residues or their mixtures, but C use efficiency （cumulative respiration per unit of MBC on day 15） was greater with faba bean than with wheat and the differences among the residue mixtures were smaller at the highest clay addition rate. The MBC concentration was lowest in sole wheat and higher in residue mixtures with 50% of wheat and faba bean in the mixture or more faba bean. Soil N availability and soil pH were lower for the soil mixtures of 22% and 30% clay compared to the sandy soil alone. It could be concluded that soil cumulative respiration and MBC concentration were mainly influenced by residue addition, whereas available N and pH were influenced by clay addition to the sandy soil studied.
