A field experiment was carried out to evaluate the effects of drip fertigation combined with plant hedgerows on nitrogen and phosphorus runoff losses in intensive pear orchards in the Tai Lake Basin.Nitrogen and phosp...A field experiment was carried out to evaluate the effects of drip fertigation combined with plant hedgerows on nitrogen and phosphorus runoff losses in intensive pear orchards in the Tai Lake Basin.Nitrogen and phosphorus runoff over a whole year were measured by using successional runoff water collection devices.The four experimental treatments were conventional fertilization(CK),drip fertigation(DF),conventional fertilization combined with plant hedgerows(C+H),and drip fertigation combined with plant hedgerows(D+H).The results from one year of continuous monitoring showed a significant positive correlation between precipitation and surface runoff discharge.Surface runoff discharge under the treatments without plant hedgerows totaled 15.86%of precipitation,while surface runoff discharge under the treatments with plant hedgerows totaled 12.82%of precipitation.Plant hedgerows reduced the number of runoff events and the amount of surface runoff.Precipitation is the main driving force for the loss of nitrogen and phosphorus in surface runoff,and fertilization is an important factor affecting the losses of nitrogen and phosphorus.In CK,approximately 7.36%of nitrogen and 2.63%of phosphorus from fertilization entered the surface water through runoff.Drip fertigation reduced the accumulation of nitrogen and phosphorus in the surface soil and lowered the runoff loss concentrations of total nitrogen(TN)and total phosphorus(TP).Drip fertigation combined with plant hedgerows significantly reduced the overall TN and TP losses by 45.38 and 36.81%,respectively,in comparison to the CK totals.Drip fertigation increased the vertical migration depth of nitrogen and phosphorus nutrients and reduced the accumulation of nitrogen and phosphorus in the surface soil,which increased the pear yield.The promotion of drip fertigation combined with plant hedgerows will greatly reduce the losses of nitrogen and phosphorus to runoff and maintain the high fruit yields in the intensive orchards of the Tai Lake Basin.展开更多
The present study aimed to investigate avian diversity in hedgerows at Angacha, in the Kembatta zone, Ethiopia. Transect and point-count methods were deployed to determine avian diversity, species richness, similarity...The present study aimed to investigate avian diversity in hedgerows at Angacha, in the Kembatta zone, Ethiopia. Transect and point-count methods were deployed to determine avian diversity, species richness, similarity and preferences across five sub study sites. Diversity and preferences of birds to hedgerow types varied in relation to their vegetation composition and structure. Five endemic species, i.e., Rüppel’s Black Chat (Cossyfa semirufa), the White-cheeked Turaco (Tauraco leucotis), the Banded Barbet (Lybius undatus), the Abyssinian Oriole (Oriolus monacha) and the Wattled Ibis (Bostrychia carucullatta) were recorded in the thick hedgerow type. Thickness, height and width of hedgerows affected the diversity, distribution and habitat preference of birds. Thick hedgerow types showed the highest avian species diversity, richness and similarity. There was a high correlation between the hedgerow diversity and its bird diversity, which was directly associated with habitat quality. Bird species diversity and preference for hedgerow types require important conservation and management priorities.展开更多
Soil and water loss has been a major environmental problem in the Danjiangkou Reservoir Region.A study of 14°sloping farmland was performed on impact of different contour hedgerows on runoff,losses of soil and nu...Soil and water loss has been a major environmental problem in the Danjiangkou Reservoir Region.A study of 14°sloping farmland was performed on impact of different contour hedgerows on runoff,losses of soil and nutrients during 2008 and 2011,with five treatments and three replications.The winter wheat and summer maize were used as the test crops.Treatments consisted of four hedgerows:Amorpha(Amorpha fruticosa L.),Honeysuckle(Lonicera japonica Thunb.),Day-lily flower(Hemerocallis citrina Baroni.),and Sabaigrass(Eulaliopsis binata),and a control without hedgerow.Result showed that the runoff under the control treatment was much higher than that of hedgerows.Amorpha could reduce the runoff by 35.2%compared with the control.Soil losses in four hedgerows showed significant reduction in four years(e.g.,Amorpha:78.3%;Honeysuckle:77.1%).Nutrient losses in winter were much higher than that in summer,especially total nitrogen,total phosphorus and total potassium,even though there was an abundant precipitation in summer.Hedgerows greatly affected the soil and nutrient losses on slopping farmland compared with the control treatment,especially Amorpha treatment.The present study found that the Amorpha could be used as the hedgerow species for reducing soil and water loss in the Danjiangkou Reservoir Region.展开更多
The impulse to remain profitable by increasing agricultural production levels in view of the greater demand for food, provided impetus to production intensification. The aim of this review is to summarise current lite...The impulse to remain profitable by increasing agricultural production levels in view of the greater demand for food, provided impetus to production intensification. The aim of this review is to summarise current literature, reporting specifically on the impact of production intensification on habitats and yield constraints caused by weeds. Secondly, in alleviating these effects over the short term, ecological measures that enhance species diversity in conserved habitats and promote semi-natural habitats in the agricultural landscape, are discussed. In large-scale intensive agriculture, weed control is predominantly rooted in agrochemical applications in the form of herbicides. Long lasting intensive agricultural practices show discord both with the promotion of the biodiversity of microbes belowground and aboveground and with organisms involved in the breaking down of plant material. The presence of native species in the surroundings, in combination with hedgerows and field margins, with a comparatively intricate and balanced variety of plants in a sheltered environment, are essential for settlement of benign insects, particularly in the face of intensive agricultural production. The promising tactic of advantageous seed predators enables decreased herbicide applications. Crop mosaics arranged to advance compatibility at the landscape scale are important to bolster pollination services and insect management, while ecological variety in the surroundings acts as a safety net for habitat diversity. Weed control in combination with different tactics of vegetation use, comprising cover cropping, hedgerows and field margins, sets up safe havens in the landscape, and improves the diffusion of complementary life forms. Field margins perform a meaningful natural function as point of provision for forage, safe havens and distribution passageways for pollinators and insect predators. Production practices that promote more heterogeneity and combine high density semi-natural safe havens and habitat conservation in agro ecosystems are beneficial to species diversity across trophic levels and contribute to agricultural production stability and food safety.展开更多
Hedgerows with intercropping systems were established at the ICIMOD test and demonstration site at Godawari to assess the effective- ness of Sloping Agricultural Land Technology （SALT） in reducing run- off water vol...Hedgerows with intercropping systems were established at the ICIMOD test and demonstration site at Godawari to assess the effective- ness of Sloping Agricultural Land Technology （SALT） in reducing run- off water volume, controlling soil loss, increasing crop production, and improving soil fertility in the mid-hills of Nepal. Runoff water volume （1996-2002）, soil loss （1996-2002） and maize yield （1995-2001）, and soil fertility-related parameters were assessed on SALT models with three factors： the type of nitrogen-fixing plant, the farmers＇ practice, and fertilizer use. Results showed a significant effect of Alnus nepalensis and/or Indigofera dosua on runoff water volume, soil loss, crop produc- tion, soil water retention, and soil nutrients （NPK）. Farmers＇ practice and fertilization did not play a significant role in reducing runoff water and soil loss. However, farmers＇ practice significantly increased crop produc- tion. Therefore, integrating soil conservation approaches on SALT sys- tems enhances stable economic output to hills and mountain farmers.展开更多
Planting oil mallee (Eucalyptus spp.) belts in cropping fields introduces a new native, perennial-based habitat type to the previously homogenous, exotic, annual-based cropping environment. The purpose of this investi...Planting oil mallee (Eucalyptus spp.) belts in cropping fields introduces a new native, perennial-based habitat type to the previously homogenous, exotic, annual-based cropping environment. The purpose of this investigation was to determine if oil mallee plantings enhance the diversity and abundance of ground-dwelling invertebrates, especially beetles, in an agro-forestry landscape by comparing four habitat types (wheat field, oil mallee belts, remnant woodland, and remnant roadside vegetation). Belts of oil mallees within a cropping paddock had substantially different assemblages of ground dwelling arthropod orders to the surrounding wheat crop. Of 93 coleopteran species trapped, 27 were found throughout all four habitats in the landscape, with the remaining species creating a strong distinction between the assemblages in the cropped areas and other habitat types in terms of species competition, diversity and abundance. Coleopteran assemblages in oil mallees were more similar to those in woodland and roadside remnants than to those in the adjacent wheat crop. Arthropod assemblages, in particular coleopterans, within this agricultural environment were thus influenced by habitat type. Oil mallee farming systems appear beneficial for arthropod conservation in the wheat belt of Western Australia.展开更多
In a long term study photosynthetically active radiation was monitored for three rainy seasons to measure the effects of hedgerow intercropping in rotation with maize and cowpea in a senna/siamea and panicum/grass str...In a long term study photosynthetically active radiation was monitored for three rainy seasons to measure the effects of hedgerow intercropping in rotation with maize and cowpea in a senna/siamea and panicum/grass strip on biomass yield and light use efficiency. Maize/cowpea intercropped with senna siamea or grass stripped were compared with sole maize and cowpea. A ceptometer was applied to measure PAR interception by sole maize or cowpea or crop/tree and grass/crop interfaces and separation of PAR used by each plant or tree/grass component. Hedgerow intercropping increased PAR interception and biomass formation. C4 plants had higher LUE than C3 plants while combining C4 and C3 in the agroforestry system lowered LUE. The tree/crop interfaces increased PAR interception than at 1 m and 2 m away from the hedgerow. The row of maize or cowpea at lm intercepted more PAR than the row at 2 m from hedgerow while the cowpea row next to the hedgerow was depressed compared to the rows in the middle rows which had higher yields. The maize or cowpea row next to the grass strip was more stressed than the rows in the middle of the alley.展开更多
Characteristics of soil erosion change along a long slope in the gentle hilly areas in black soil region in Northeast China are discussed. A simplified slope model based on segments was used to analyze the runoff data...Characteristics of soil erosion change along a long slope in the gentle hilly areas in black soil region in Northeast China are discussed. A simplified slope model based on segments was used to analyze the runoff data and soil erosion data observed between 2003 and 2004 over 10 field plots with different slope length in Heshan Farm, Heilongjiang Province. We found that soil erosion rate over long slopes in the black soil region changed alternatively along the slope and creates alternative zones of intensive erosion and week erosion.The exact place of each zone is different for different rainfall conditions. In a year with less and mild precipitation, rill cannot happen within the top 50 m, while in a year with large and intensive precipitation, rill can be formed starting even at 15 m from the top of the slope.展开更多
A litterbag experiment of 12 weeks was conducted to study nitrogenmineralization process of prunings of six nitrogen-fixing hedgerowspecies in a dry valley of the Jinsha River. Prunigns wereincorporated into soil or u...A litterbag experiment of 12 weeks was conducted to study nitrogenmineralization process of prunings of six nitrogen-fixing hedgerowspecies in a dry valley of the Jinsha River. Prunigns wereincorporated into soil or used as mulch. The results indicated thatpruning N of the six hedgerow species was mineralized fast in thefirst week and then decreased slowly in the rest of the study period.When prunings were incorporated into soil, the amount of nitrogenmineralized by the end of the first week accounted for 69.9/100,58.2/100, 54.5/100, 43.0/100, 29.6/100 and 20.6/100 of the total N inprungins of Desmodium rensonii, Tephrosia candida, Leucaenaleucoephala, Albizia yunnanensis, Acacia dealbata, and Acaciamearnsii, respectively.展开更多
Eutrophication is recognized as one of the major environmental problems in the Three Gorges Reservoir.Contour hedgerows have been used as a major soil and water conservation measure in this area.Accordingly,a two-year...Eutrophication is recognized as one of the major environmental problems in the Three Gorges Reservoir.Contour hedgerows have been used as a major soil and water conservation measure in this area.Accordingly,a two-year study was conducted to investigate the effects of contour hedgerow intercropping on nutrient loss from sloping farmland in this area.Four treatments were applied:(1) Maize + Soybean,(2) Maize,(3) Maize + Alfalfa,and(4) Maize + Hemerocallis citrina Baroni.Results indicated that nutrient loss in the control treatment(Maize) was serious,especially the average loss flux of total nitrogen(2245.8 mg) and total phosphate(2434.2 mg) in a typical rainfall event.However,the nutrient losses by runoff in the other three treatments with contour hedgerow intercropping showed significant reduction.Compared with the control treatment,the total nitrogen loss in the Alfalfa and Hemerocallis citrina Baroni decreased by 80.9% and 85.0%,respectively,and the total phosphorus loss in the two treatments decreased by 91.2% and 92.5%,respectively.Therefore,it is concluded that nutrient losses could be reduced by using contour hedgerows in the Three Gorges Region.Reducing runoff volume and sediment loss was the main mechanisms of contour hedgerow intercropping to reduce nutrient loss.展开更多
The disease types, symptom characteristics, pathogenesis and ecological control technology of hedgerow commonly used in landscape greening in Nanjing, Zhenjiang, Changzhou, Wuxi and Suzhou were systematically studied....The disease types, symptom characteristics, pathogenesis and ecological control technology of hedgerow commonly used in landscape greening in Nanjing, Zhenjiang, Changzhou, Wuxi and Suzhou were systematically studied. The results showed that there were 10 kinds of common diseases of flowers and shrubs in landscape greening in five cities of southern Jiangsu. Among them, 8 were caused by deuteromycotina and 2 were caused by subphylum basidiomycetes. It was pointed out that the disease regularity was directly related to the pathogenic bacteria, temperature and humidity, microclimate and hedgerow growth. For the first time, the ecological control method of hedgerow disease which focused on ecological health maintenance was put forward.展开更多
The increased application of chemical fertilizers in citrus orchards and the non-point source nitrogen(N) and phosphorus(P)diffusion threaten the fresh water quality of the Three Gorges Reservoir area of China. A 10-y...The increased application of chemical fertilizers in citrus orchards and the non-point source nitrogen(N) and phosphorus(P)diffusion threaten the fresh water quality of the Three Gorges Reservoir area of China. A 10-year field trial on sloping citrus lands was conducted to evaluate five protection methods for reducing N and P losses: 1) intercropping with perennial white clover(CW); 2) straw mulching of the soil surface(CS); 3) intercropping with yellow daylily contour hedgerows(CH); 4) an impermeable membrane buried in the soil along the contour lines(CM); and 5) intercropping with a rotation of wheat and peanut(CWP). An area of conventional citrus management was also maintained as the control(CK). The results showed that CM and CH were the most effective methods for reducing surface runoff. The sediment yield were reduced at the highest rate by CW and CH and was also significantly reduced by CS. Reduced runoff volume and sediment yield were the crucial mechanism for the reductions in N and P losses. Compared with the control, CW, CS, CH, and CM reduced annual runoff by 9%, 13%, 25%, and 30%, sediment yield by 77%, 55%, 71%, and 28%,N loss by 10%, 23% 36%, and 37%, and P loss by 39%, 31%, 27%, and 25%, respectively. CW, CS, CH, and CM were effective in reducing N and P losses from the sloping citrus land. However, over the long-term, surface soil nutrient accumulation in CW, CS, and CH diminished the benefit of those methods in reducing N and P losses. In addition, CWP increased soil erosion and nutrient loss,which showed that citrus intercropping with other crops was an unsuitable method for citrus sloping land in the Three Gorges area.展开更多
Given the impermeability,larger dosage,and higher drift of pesticides used in modern hedgerow vine canopies,a novel tunnel-convective air-assisted spraying technology was proposed.Mechanized spraying equipment with hi...Given the impermeability,larger dosage,and higher drift of pesticides used in modern hedgerow vine canopies,a novel tunnel-convective air-assisted spraying technology was proposed.Mechanized spraying equipment with high penetration and low drift was developed.The air-assisted system of this equipment was centrosymmetric,and the fan type was cross-flow.The fan outlet width was 138 mm and the air duct’s main body followed a logarithmic spiral profile,based on parallel flow theory.The external diameter of the impeller was 157 mm,which was fixed into a barrel structure by 23 strong forward-curved blades,each being 1 mm thick.The central angle of the blades was 108°,and the ratio of the internal and external diameters was 0.81.The impeller and air duct served as guides to circulate and reciprocate airflow around the crown,forming a tunnel-convective air-assisted to the vine.Using MATLAB interpolation,the airflow trajectory of the air convection circulation in the door-shaped cover was obtained.The velocity field distribution test showed that,in the case of a canopy,there were tunnel-convective circulating airflows with high velocity on both sides and uniform velocity in the middle of the canopy.Due to the tunnel-convective air-assisted spraying technology,the vertical distribution uniformity of spray deposition has been significantly improved,spray penetration has been enhanced,penetrability has been effectively improved,and droplets on the ground and in the air have been significantly reduced.The results of this study can assist in providing further optimization and improvement of plant protection machinery.The new tunnel-convective air-assisted spraying technology may be a more favorable choice for future spray applications and the environment.展开更多
基金supported by the International S&T Cooperation Program of Shanghai,China(20390731200)the Major Science and Technology Program for Water Pollution Control and Treatment,China(2017ZX07205)。
文摘A field experiment was carried out to evaluate the effects of drip fertigation combined with plant hedgerows on nitrogen and phosphorus runoff losses in intensive pear orchards in the Tai Lake Basin.Nitrogen and phosphorus runoff over a whole year were measured by using successional runoff water collection devices.The four experimental treatments were conventional fertilization(CK),drip fertigation(DF),conventional fertilization combined with plant hedgerows(C+H),and drip fertigation combined with plant hedgerows(D+H).The results from one year of continuous monitoring showed a significant positive correlation between precipitation and surface runoff discharge.Surface runoff discharge under the treatments without plant hedgerows totaled 15.86%of precipitation,while surface runoff discharge under the treatments with plant hedgerows totaled 12.82%of precipitation.Plant hedgerows reduced the number of runoff events and the amount of surface runoff.Precipitation is the main driving force for the loss of nitrogen and phosphorus in surface runoff,and fertilization is an important factor affecting the losses of nitrogen and phosphorus.In CK,approximately 7.36%of nitrogen and 2.63%of phosphorus from fertilization entered the surface water through runoff.Drip fertigation reduced the accumulation of nitrogen and phosphorus in the surface soil and lowered the runoff loss concentrations of total nitrogen(TN)and total phosphorus(TP).Drip fertigation combined with plant hedgerows significantly reduced the overall TN and TP losses by 45.38 and 36.81%,respectively,in comparison to the CK totals.Drip fertigation increased the vertical migration depth of nitrogen and phosphorus nutrients and reduced the accumulation of nitrogen and phosphorus in the surface soil,which increased the pear yield.The promotion of drip fertigation combined with plant hedgerows will greatly reduce the losses of nitrogen and phosphorus to runoff and maintain the high fruit yields in the intensive orchards of the Tai Lake Basin.
文摘The present study aimed to investigate avian diversity in hedgerows at Angacha, in the Kembatta zone, Ethiopia. Transect and point-count methods were deployed to determine avian diversity, species richness, similarity and preferences across five sub study sites. Diversity and preferences of birds to hedgerow types varied in relation to their vegetation composition and structure. Five endemic species, i.e., Rüppel’s Black Chat (Cossyfa semirufa), the White-cheeked Turaco (Tauraco leucotis), the Banded Barbet (Lybius undatus), the Abyssinian Oriole (Oriolus monacha) and the Wattled Ibis (Bostrychia carucullatta) were recorded in the thick hedgerow type. Thickness, height and width of hedgerows affected the diversity, distribution and habitat preference of birds. Thick hedgerow types showed the highest avian species diversity, richness and similarity. There was a high correlation between the hedgerow diversity and its bird diversity, which was directly associated with habitat quality. Bird species diversity and preference for hedgerow types require important conservation and management priorities.
文摘Soil and water loss has been a major environmental problem in the Danjiangkou Reservoir Region.A study of 14°sloping farmland was performed on impact of different contour hedgerows on runoff,losses of soil and nutrients during 2008 and 2011,with five treatments and three replications.The winter wheat and summer maize were used as the test crops.Treatments consisted of four hedgerows:Amorpha(Amorpha fruticosa L.),Honeysuckle(Lonicera japonica Thunb.),Day-lily flower(Hemerocallis citrina Baroni.),and Sabaigrass(Eulaliopsis binata),and a control without hedgerow.Result showed that the runoff under the control treatment was much higher than that of hedgerows.Amorpha could reduce the runoff by 35.2%compared with the control.Soil losses in four hedgerows showed significant reduction in four years(e.g.,Amorpha:78.3%;Honeysuckle:77.1%).Nutrient losses in winter were much higher than that in summer,especially total nitrogen,total phosphorus and total potassium,even though there was an abundant precipitation in summer.Hedgerows greatly affected the soil and nutrient losses on slopping farmland compared with the control treatment,especially Amorpha treatment.The present study found that the Amorpha could be used as the hedgerow species for reducing soil and water loss in the Danjiangkou Reservoir Region.
文摘The impulse to remain profitable by increasing agricultural production levels in view of the greater demand for food, provided impetus to production intensification. The aim of this review is to summarise current literature, reporting specifically on the impact of production intensification on habitats and yield constraints caused by weeds. Secondly, in alleviating these effects over the short term, ecological measures that enhance species diversity in conserved habitats and promote semi-natural habitats in the agricultural landscape, are discussed. In large-scale intensive agriculture, weed control is predominantly rooted in agrochemical applications in the form of herbicides. Long lasting intensive agricultural practices show discord both with the promotion of the biodiversity of microbes belowground and aboveground and with organisms involved in the breaking down of plant material. The presence of native species in the surroundings, in combination with hedgerows and field margins, with a comparatively intricate and balanced variety of plants in a sheltered environment, are essential for settlement of benign insects, particularly in the face of intensive agricultural production. The promising tactic of advantageous seed predators enables decreased herbicide applications. Crop mosaics arranged to advance compatibility at the landscape scale are important to bolster pollination services and insect management, while ecological variety in the surroundings acts as a safety net for habitat diversity. Weed control in combination with different tactics of vegetation use, comprising cover cropping, hedgerows and field margins, sets up safe havens in the landscape, and improves the diffusion of complementary life forms. Field margins perform a meaningful natural function as point of provision for forage, safe havens and distribution passageways for pollinators and insect predators. Production practices that promote more heterogeneity and combine high density semi-natural safe havens and habitat conservation in agro ecosystems are beneficial to species diversity across trophic levels and contribute to agricultural production stability and food safety.
基金supported in part by the Nepal Academy of Science and Technology(NAST)
文摘Hedgerows with intercropping systems were established at the ICIMOD test and demonstration site at Godawari to assess the effective- ness of Sloping Agricultural Land Technology （SALT） in reducing run- off water volume, controlling soil loss, increasing crop production, and improving soil fertility in the mid-hills of Nepal. Runoff water volume （1996-2002）, soil loss （1996-2002） and maize yield （1995-2001）, and soil fertility-related parameters were assessed on SALT models with three factors： the type of nitrogen-fixing plant, the farmers＇ practice, and fertilizer use. Results showed a significant effect of Alnus nepalensis and/or Indigofera dosua on runoff water volume, soil loss, crop produc- tion, soil water retention, and soil nutrients （NPK）. Farmers＇ practice and fertilization did not play a significant role in reducing runoff water and soil loss. However, farmers＇ practice significantly increased crop produc- tion. Therefore, integrating soil conservation approaches on SALT sys- tems enhances stable economic output to hills and mountain farmers.
文摘Planting oil mallee (Eucalyptus spp.) belts in cropping fields introduces a new native, perennial-based habitat type to the previously homogenous, exotic, annual-based cropping environment. The purpose of this investigation was to determine if oil mallee plantings enhance the diversity and abundance of ground-dwelling invertebrates, especially beetles, in an agro-forestry landscape by comparing four habitat types (wheat field, oil mallee belts, remnant woodland, and remnant roadside vegetation). Belts of oil mallees within a cropping paddock had substantially different assemblages of ground dwelling arthropod orders to the surrounding wheat crop. Of 93 coleopteran species trapped, 27 were found throughout all four habitats in the landscape, with the remaining species creating a strong distinction between the assemblages in the cropped areas and other habitat types in terms of species competition, diversity and abundance. Coleopteran assemblages in oil mallees were more similar to those in woodland and roadside remnants than to those in the adjacent wheat crop. Arthropod assemblages, in particular coleopterans, within this agricultural environment were thus influenced by habitat type. Oil mallee farming systems appear beneficial for arthropod conservation in the wheat belt of Western Australia.
文摘In a long term study photosynthetically active radiation was monitored for three rainy seasons to measure the effects of hedgerow intercropping in rotation with maize and cowpea in a senna/siamea and panicum/grass strip on biomass yield and light use efficiency. Maize/cowpea intercropped with senna siamea or grass stripped were compared with sole maize and cowpea. A ceptometer was applied to measure PAR interception by sole maize or cowpea or crop/tree and grass/crop interfaces and separation of PAR used by each plant or tree/grass component. Hedgerow intercropping increased PAR interception and biomass formation. C4 plants had higher LUE than C3 plants while combining C4 and C3 in the agroforestry system lowered LUE. The tree/crop interfaces increased PAR interception than at 1 m and 2 m away from the hedgerow. The row of maize or cowpea at lm intercepted more PAR than the row at 2 m from hedgerow while the cowpea row next to the hedgerow was depressed compared to the rows in the middle rows which had higher yields. The maize or cowpea row next to the grass strip was more stressed than the rows in the middle of the alley.
基金National Basic Research Program of China, No.2007CB407207Knowledge Innovation Project of Institute of Geographic Sciences and Natural Resources Research,CAS,No.CXIOG-A04-10the support from CAS through its "One Hundred Talent" program
文摘Characteristics of soil erosion change along a long slope in the gentle hilly areas in black soil region in Northeast China are discussed. A simplified slope model based on segments was used to analyze the runoff data and soil erosion data observed between 2003 and 2004 over 10 field plots with different slope length in Heshan Farm, Heilongjiang Province. We found that soil erosion rate over long slopes in the black soil region changed alternatively along the slope and creates alternative zones of intensive erosion and week erosion.The exact place of each zone is different for different rainfall conditions. In a year with less and mild precipitation, rill cannot happen within the top 50 m, while in a year with large and intensive precipitation, rill can be formed starting even at 15 m from the top of the slope.
基金Project supported jointly by the Chengdu Di Ao Science Foundation and the Sichuan Provincial Science Foundation for Young Scient
文摘A litterbag experiment of 12 weeks was conducted to study nitrogenmineralization process of prunings of six nitrogen-fixing hedgerowspecies in a dry valley of the Jinsha River. Prunigns wereincorporated into soil or used as mulch. The results indicated thatpruning N of the six hedgerow species was mineralized fast in thefirst week and then decreased slowly in the rest of the study period.When prunings were incorporated into soil, the amount of nitrogenmineralized by the end of the first week accounted for 69.9/100,58.2/100, 54.5/100, 43.0/100, 29.6/100 and 20.6/100 of the total N inprungins of Desmodium rensonii, Tephrosia candida, Leucaenaleucoephala, Albizia yunnanensis, Acacia dealbata, and Acaciamearnsii, respectively.
基金by the National Science & Technology Pillar Program (Grant No. 2009ZX07104-002)the CAS Actionplan for West Development (GrantNo. KZCX2-XB3-09)the Natural Science Foundation of China (Grant No. 40901255)
文摘Eutrophication is recognized as one of the major environmental problems in the Three Gorges Reservoir.Contour hedgerows have been used as a major soil and water conservation measure in this area.Accordingly,a two-year study was conducted to investigate the effects of contour hedgerow intercropping on nutrient loss from sloping farmland in this area.Four treatments were applied:(1) Maize + Soybean,(2) Maize,(3) Maize + Alfalfa,and(4) Maize + Hemerocallis citrina Baroni.Results indicated that nutrient loss in the control treatment(Maize) was serious,especially the average loss flux of total nitrogen(2245.8 mg) and total phosphate(2434.2 mg) in a typical rainfall event.However,the nutrient losses by runoff in the other three treatments with contour hedgerow intercropping showed significant reduction.Compared with the control treatment,the total nitrogen loss in the Alfalfa and Hemerocallis citrina Baroni decreased by 80.9% and 85.0%,respectively,and the total phosphorus loss in the two treatments decreased by 91.2% and 92.5%,respectively.Therefore,it is concluded that nutrient losses could be reduced by using contour hedgerows in the Three Gorges Region.Reducing runoff volume and sediment loss was the main mechanisms of contour hedgerow intercropping to reduce nutrient loss.
文摘The disease types, symptom characteristics, pathogenesis and ecological control technology of hedgerow commonly used in landscape greening in Nanjing, Zhenjiang, Changzhou, Wuxi and Suzhou were systematically studied. The results showed that there were 10 kinds of common diseases of flowers and shrubs in landscape greening in five cities of southern Jiangsu. Among them, 8 were caused by deuteromycotina and 2 were caused by subphylum basidiomycetes. It was pointed out that the disease regularity was directly related to the pathogenic bacteria, temperature and humidity, microclimate and hedgerow growth. For the first time, the ecological control method of hedgerow disease which focused on ecological health maintenance was put forward.
基金supported by the Eco-environmental Monitoring Network of the Three Gorges Project, Three Gorges Project Construction Committee of the State Council, Chinathe National Natural Science Foundation of China (Nos. 40871147 and 30870410)
文摘The increased application of chemical fertilizers in citrus orchards and the non-point source nitrogen(N) and phosphorus(P)diffusion threaten the fresh water quality of the Three Gorges Reservoir area of China. A 10-year field trial on sloping citrus lands was conducted to evaluate five protection methods for reducing N and P losses: 1) intercropping with perennial white clover(CW); 2) straw mulching of the soil surface(CS); 3) intercropping with yellow daylily contour hedgerows(CH); 4) an impermeable membrane buried in the soil along the contour lines(CM); and 5) intercropping with a rotation of wheat and peanut(CWP). An area of conventional citrus management was also maintained as the control(CK). The results showed that CM and CH were the most effective methods for reducing surface runoff. The sediment yield were reduced at the highest rate by CW and CH and was also significantly reduced by CS. Reduced runoff volume and sediment yield were the crucial mechanism for the reductions in N and P losses. Compared with the control, CW, CS, CH, and CM reduced annual runoff by 9%, 13%, 25%, and 30%, sediment yield by 77%, 55%, 71%, and 28%,N loss by 10%, 23% 36%, and 37%, and P loss by 39%, 31%, 27%, and 25%, respectively. CW, CS, CH, and CM were effective in reducing N and P losses from the sloping citrus land. However, over the long-term, surface soil nutrient accumulation in CW, CS, and CH diminished the benefit of those methods in reducing N and P losses. In addition, CWP increased soil erosion and nutrient loss,which showed that citrus intercropping with other crops was an unsuitable method for citrus sloping land in the Three Gorges area.
基金the National Natural Science Foundation of China(Grant No.51805271)Jiangsu Agricultural Science and Technology Innovation Fund(CX203172,CX181007)+1 种基金‘Qinglan Project’of Jiangsu Province(QLGC)the Fundamental Research Funds for the Central Universities(KYXK2021001).
文摘Given the impermeability,larger dosage,and higher drift of pesticides used in modern hedgerow vine canopies,a novel tunnel-convective air-assisted spraying technology was proposed.Mechanized spraying equipment with high penetration and low drift was developed.The air-assisted system of this equipment was centrosymmetric,and the fan type was cross-flow.The fan outlet width was 138 mm and the air duct’s main body followed a logarithmic spiral profile,based on parallel flow theory.The external diameter of the impeller was 157 mm,which was fixed into a barrel structure by 23 strong forward-curved blades,each being 1 mm thick.The central angle of the blades was 108°,and the ratio of the internal and external diameters was 0.81.The impeller and air duct served as guides to circulate and reciprocate airflow around the crown,forming a tunnel-convective air-assisted to the vine.Using MATLAB interpolation,the airflow trajectory of the air convection circulation in the door-shaped cover was obtained.The velocity field distribution test showed that,in the case of a canopy,there were tunnel-convective circulating airflows with high velocity on both sides and uniform velocity in the middle of the canopy.Due to the tunnel-convective air-assisted spraying technology,the vertical distribution uniformity of spray deposition has been significantly improved,spray penetration has been enhanced,penetrability has been effectively improved,and droplets on the ground and in the air have been significantly reduced.The results of this study can assist in providing further optimization and improvement of plant protection machinery.The new tunnel-convective air-assisted spraying technology may be a more favorable choice for future spray applications and the environment.
