Biochar addition can improve the physical and hydraulic characteristics of sandy soil.This study investigated the effects of biochar on water holding capacity and water movement in sandy soil under drip irrigation.By ...Biochar addition can improve the physical and hydraulic characteristics of sandy soil.This study investigated the effects of biochar on water holding capacity and water movement in sandy soil under drip irrigation.By indoor simulation experiments,the effects of biochar application at five levels(0%,1%,2%,4%and 6%)on the soil water retention curve,infiltration characteristics of drip irrigation and water distribution were tested and analyzed.The results showed that biochar addition rate was positively correlated with water holding capacity of sandy soil and soil available water.Within the same infiltration time,with an increasing amount of added biochar,the diffusion distance of the horizontal wetting front(HWF)tended to decrease,while the infiltration distance of vertical wetting front(VWF)initially declined and then rose.The features of wetted bodies changed from"broad-shallow"to"narrow-deep"type.The relationship between the transport distances of HWF and VWF and the infiltration time was described by a power function.At the same distance from the point source,the larger the amount of added biochar,the higher the soil water content.Biochar had a great influence on the water content of the layer with biochar(0–200 mm)and had some effects at 200–250 mm without biochar;but it had less influence on the soil water content deeper than 250 mm.For the application rate of biochar of 4%,most water was retained within 0–250 mm soil layer.However,when biochar application amount was high(6%),it would be helpful for water infiltration.During the improvement of sandy soil,biochar application rate of 4%in the plow layer had the best effect.展开更多
In this paper, we discuss charcoalified foxtail millet grains dated to the middle to late Western Zhou Dynasty and collected from the Chenyuan archeological site in Shangluo, in China's southeastern Shaanxi Provin...In this paper, we discuss charcoalified foxtail millet grains dated to the middle to late Western Zhou Dynasty and collected from the Chenyuan archeological site in Shangluo, in China's southeastern Shaanxi Province. We assigned these specimens to the species Setaria italica based on the following characteristics: an obtuse chalazal apex with missing stigmatic remains; an undulant seed surface composed of rectangular cells with undulate anticlinal walls; an elongated and deeply depressed embryo extending to almost the full seed length; and spherical starch grains. We suggest that the spread of foxtail millet from its original northern distribution center to the southern slopes of the Qinling Mountains could be attributed to: its prominence across Zhou crop systems; the latter area's arid or subarid climate; and the migration south of Zhou people fleeing severe conflict between their nation and northern nomads.展开更多
The Bryaceae is a large, cosmopolitan, taxonomically difficult moss family. Recent studies based on molecular data alone or in combination with morphological data have greatly changed the understanding of phylogenetic...The Bryaceae is a large, cosmopolitan, taxonomically difficult moss family. Recent studies based on molecular data alone or in combination with morphological data have greatly changed the understanding of phylogenetic relationships in the Bryaceae s.l. and indicate that the Bryaceae is not monophyletic. Based on phylogenetic analyses of sequence data for four cpDNA regions and morphological data, we revise the traditional Bryaceae in China and transfer six genera to other families. The Mielichhoferiaceae was redefined previously by Hill et al. based on the presence of much-branched stems, apparently lateral gametangia, Pohlia-like leaves, and a more-or-less reduced peristome. Five genera of Mielichhoferiaceae are present in China: Mielichhoferia(four species), Pohlia(27 species, two varieties), Pseudopohlia(one species), Epipterygium(two species), and Synthetodontium(one species). The genera Orthodontium and Leptobryum are transferred from the Bryaceae s.l. to Orthodontiaceae and Meesiaceae, respectively. Members of the recircumscribed Bryaceae belong to five genera: Anomobryum(five species), Brachymenium(14 species), Bryum(54 species, two varieties), Plagiobryum(three species), and Rhodobryum(four species). Bryaceae diversity is high in China. The species have potential uses in medicine, landscaping, environmental protection, and other fields. Rhodobryum roseum(Hedw.) Limpr., Bryum argenteum Hedw., and Rhodobryum giganteum(Schw gr.) Paris have long been used to cure cardiovascular disease in China. Some bioactive compounds will be leading compounds for the future design of novel drugs. In recent years, many species of Bryaceae have been used for landscaping. Bryum spp. are the dominant biotic species in biological soil crusts, which serve important ecological protective functions.展开更多
基金supported by the Special Fund for Agro-scientific Research in the Public Interest(20130313006,201503136)the National Natural Science Foundation of China(31660073)+1 种基金the National Key Research and Development Program of China(2017YFD0200803-04,2018YFD0800804,2017YFD0201900)the Youth Foundation of Xinjiang Academy of Agricultural Sciences(xjnkq-2015002)
文摘Biochar addition can improve the physical and hydraulic characteristics of sandy soil.This study investigated the effects of biochar on water holding capacity and water movement in sandy soil under drip irrigation.By indoor simulation experiments,the effects of biochar application at five levels(0%,1%,2%,4%and 6%)on the soil water retention curve,infiltration characteristics of drip irrigation and water distribution were tested and analyzed.The results showed that biochar addition rate was positively correlated with water holding capacity of sandy soil and soil available water.Within the same infiltration time,with an increasing amount of added biochar,the diffusion distance of the horizontal wetting front(HWF)tended to decrease,while the infiltration distance of vertical wetting front(VWF)initially declined and then rose.The features of wetted bodies changed from"broad-shallow"to"narrow-deep"type.The relationship between the transport distances of HWF and VWF and the infiltration time was described by a power function.At the same distance from the point source,the larger the amount of added biochar,the higher the soil water content.Biochar had a great influence on the water content of the layer with biochar(0–200 mm)and had some effects at 200–250 mm without biochar;but it had less influence on the soil water content deeper than 250 mm.For the application rate of biochar of 4%,most water was retained within 0–250 mm soil layer.However,when biochar application amount was high(6%),it would be helpful for water infiltration.During the improvement of sandy soil,biochar application rate of 4%in the plow layer had the best effect.
基金supported by the National Natural Science Foundation of China(31070184,30370237,90202019,40325007 and 40121303)the Special Fund of Palaeontology and Palaeoanthropology,Academia Sinica(SFPPAS,9713)the Overseas Outstanding Scholar Foundation of Chinese Academy of Sciences(2003-1-7)
文摘In this paper, we discuss charcoalified foxtail millet grains dated to the middle to late Western Zhou Dynasty and collected from the Chenyuan archeological site in Shangluo, in China's southeastern Shaanxi Province. We assigned these specimens to the species Setaria italica based on the following characteristics: an obtuse chalazal apex with missing stigmatic remains; an undulant seed surface composed of rectangular cells with undulate anticlinal walls; an elongated and deeply depressed embryo extending to almost the full seed length; and spherical starch grains. We suggest that the spread of foxtail millet from its original northern distribution center to the southern slopes of the Qinling Mountains could be attributed to: its prominence across Zhou crop systems; the latter area's arid or subarid climate; and the migration south of Zhou people fleeing severe conflict between their nation and northern nomads.
基金supported by the National Natural Science Foundation of China(31070184,31370237)the Natural Science Foundation of Hebei Province(2012205026)+1 种基金Special Fund on Public Health from the Central Finance“Resource survey and monitoring on original plant of essential med-icine”(Cai She[2001]76)Special Fund of the National Traditional Chinese Medicine(201207002)
文摘The Bryaceae is a large, cosmopolitan, taxonomically difficult moss family. Recent studies based on molecular data alone or in combination with morphological data have greatly changed the understanding of phylogenetic relationships in the Bryaceae s.l. and indicate that the Bryaceae is not monophyletic. Based on phylogenetic analyses of sequence data for four cpDNA regions and morphological data, we revise the traditional Bryaceae in China and transfer six genera to other families. The Mielichhoferiaceae was redefined previously by Hill et al. based on the presence of much-branched stems, apparently lateral gametangia, Pohlia-like leaves, and a more-or-less reduced peristome. Five genera of Mielichhoferiaceae are present in China: Mielichhoferia(four species), Pohlia(27 species, two varieties), Pseudopohlia(one species), Epipterygium(two species), and Synthetodontium(one species). The genera Orthodontium and Leptobryum are transferred from the Bryaceae s.l. to Orthodontiaceae and Meesiaceae, respectively. Members of the recircumscribed Bryaceae belong to five genera: Anomobryum(five species), Brachymenium(14 species), Bryum(54 species, two varieties), Plagiobryum(three species), and Rhodobryum(four species). Bryaceae diversity is high in China. The species have potential uses in medicine, landscaping, environmental protection, and other fields. Rhodobryum roseum(Hedw.) Limpr., Bryum argenteum Hedw., and Rhodobryum giganteum(Schw gr.) Paris have long been used to cure cardiovascular disease in China. Some bioactive compounds will be leading compounds for the future design of novel drugs. In recent years, many species of Bryaceae have been used for landscaping. Bryum spp. are the dominant biotic species in biological soil crusts, which serve important ecological protective functions.
