[Objective] To clarify the effects of different straw retention regimes on soil fertility in double cropping paddy field. [Method] The effects of different straw reten- tion regimes on total organic carbon (CToc), a...[Objective] To clarify the effects of different straw retention regimes on soil fertility in double cropping paddy field. [Method] The effects of different straw reten- tion regimes on total organic carbon (CToc), active carbon (CA) and mineralized carbon (CM) were analyzed, and carbon pool active (A), carbon pool active index (A/), carbon pool index (CPI) and carbon pool management index (CPMi) for each treat- ment were calculated. [Result] Compared with the unfertilized treatment (CK), CToc, CA, CM and the available ratio of soil carbon were increased in the treatment of re- turning early season and late season rice straws to field. With the same nutrient application, CToc, CA and the available ratio of soil carbon in the field with straw re- turned to field were higher than that of straw incineration and no straw returning, and the change in soil CA content was more significant. The difference in CPMI be- tween different treatments reached significant or very significant level, and the value was in the order of straw directly returned to field 〉 straw returned to field after in- cineration 〉 no straw returned to field. [Conclusion] This study provided theoretical bases for the increase of soil CA content and soil fertility in double rice fields.展开更多
Converting from conventional tillage to no-tillage influences the soil aggregate-size distribution and thus soil organic carbon (SOC) stabilization. However, the dynamics of soil aggregation and the straw-derived ca...Converting from conventional tillage to no-tillage influences the soil aggregate-size distribution and thus soil organic carbon (SOC) stabilization. However, the dynamics of soil aggregation and the straw-derived carbon (C) incorporation within aggregate fractions are not well understood. An experiment was established in 2004 to test the effects of two treatments, no-tillage with residue (NT) and conventional tillage without residue (CT), on the soil aggregate-size distribution and SOC stabilization in a continuous maize (Zea mays L.) cropping system located in the semiarid region of northern China. Soil samples were collected from the 0-10 cm layer in 2008, 2010 and 2015, and were separated into four aggregate-size classes (〉2, 0.25-2, 0.053-0.25, and 〈0.053 mm) by wet-sieving. In each year, NT soil had a higher proportion of macroaggregates (i.e., 〉2 and 0.25-2 mm) and associated SOC concentration compared with CT. Additionally, to compare straw-derived C incorporation within NT and CT aggregate fractions, ^13C-labeled straw was incubated with intact NT and CT soils. After 90 days, the highest proportion of 13C-labeled straw-derived C was observed in the 〉2 mm fraction, and this proportion was lower in NT than that in CT soil. Overall, we conclude that long-term continuous NT increased the proportion of macroaggregates and the C concentration within macroaggregates, and the physical protection provided by NT is beneficial for soil C sequestration in the continuous maize cropping system in semiarid regions of northern China.展开更多
A long-term field experiment (started at 2003) was conducted to determine the effects of different dce cultivation methods on growth characteristics and grain yield of late-season rice under double-rice cropping sys...A long-term field experiment (started at 2003) was conducted to determine the effects of different dce cultivation methods on growth characteristics and grain yield of late-season rice under double-rice cropping system in seasonal drought region of southeast China (Yujiang County, Jiangxi Province). The rice cultivation methods included no-tillage and flooded rice cultivation (N-F), no-tillage and non-flooded rice cultivation with straw mulching (N-SM), and no-tillage and non-flooded rice cultivation without straw mulching (N-ZM). There was no significant difference in rice grain yield between the N-SM and N-F treatments. However, the rice grain yields in the N-SM and N-F treatments were significantly higher than that in the N-ZM treatment. The late-season rice plants in the N-SM treatment had significantly higher numbers of effective panicles and total grains per hill compared with those in the N-ZM treatment. The above-ground dry matter of late-season rice was similar between the N-SM and N-F treatments. Compared with the N-F treatment, the N-ZM and N-SM treatments significantly decreased the leaf area at the heading stage. Moreover, the N-SM treatment could significantly increase total root length and root tip number at the grain-filling stage compared with the N-ZM treatment.展开更多
The various properties of bentonite samples with different sources and their synergistic retention effect with CPAM on wheat straw pulps were investigated. The investigated properties of bentonite included adsorptive ...The various properties of bentonite samples with different sources and their synergistic retention effect with CPAM on wheat straw pulps were investigated. The investigated properties of bentonite included adsorptive capacity based on methylene blue, cation-exchange capacity, swelling volume, colloidal volume, particle size and charge properties. The results show that particle size is the most important properties of bentonite for its synergistic retention effect with CPAM. Using Wyoming type sodium bentonite without drying after modification can obtain the excellent furnishes retention.展开更多
In this paper, a new type of retention system of PEO/cofactor retention system is introduced, the cofactors used are phenol-formaldehyde resin, wheat straw alkaline lignin and its derivatives such as hydroxymethylated...In this paper, a new type of retention system of PEO/cofactor retention system is introduced, the cofactors used are phenol-formaldehyde resin, wheat straw alkaline lignin and its derivatives such as hydroxymethylated lignin, sulfited lignin and lignin-based phenol-formaldehyde resin. The first pass retention of newsprint slurry and the properties of handsheet are improved by using the system. The results indicate that a new application field for lignin has been exploited.展开更多
Reduced tillage provides ecological and economic benefits to arable land on the Loess Plateau of China, where soil erosion has long been a serious problem and soil water availability is largely restricted. However, hi...Reduced tillage provides ecological and economic benefits to arable land on the Loess Plateau of China, where soil erosion has long been a serious problem and soil water availability is largely restricted. However, high abundances of weeds in reduced tillage systems cause significant yield losses. In this study, we explored the effects of no-tillage and stubble retention on the number and density of weeds and weed seeds in a 12-year maize-winter wheat-common vetch rotation on the Loess Plateau. Four treatments including conventional tillage, no-tillage, conventional tillage+stubble retention and no-tillage+stubble retention were designed and applied. We found that no-tillage increased the number of weed species and weed density in most of the crops, while stubble retention decreased weed density in maize and tended to suppress weeds in both no-tillage treatments(no-tillage and no-tillage+stubble retention). No-tillage led to an increase in the number of weed species in the weed seedbank and tended to increase seed density during the spring growth of winter wheat, but it decreased seed density during post-vetch fallow. Stubble retention tended to reduce seed density during the spring growth of winter wheat and post-vetch fallow. We concluded that no-tillage can promote weeds in the experimental crop rotation, while stubble retention suppresses weeds in untilled fields. The combined effects of stubble retention and no-tillage on weed suppression varied among the three crops. Based on these results, we recommend stubble retention in untilled legume-crop rotations on the Loess Plateau to improve the control of weeds.展开更多
The quality of straw affects N release after straw retention. As straw with high C: N ratio could result in N immobilization, additional N is needed to compensate N demand of crops. However, more and more N fertilize...The quality of straw affects N release after straw retention. As straw with high C: N ratio could result in N immobilization, additional N is needed to compensate N demand of crops. However, more and more N fertilizers have been applied to the soil to improve crop yields in China, which not only increases production cost but also reduces soil quality. Therefore, reasonable application of N fertilizer becomes a key problem after straw retention. This study aimed to assess the effects of applying maize straw with high quality alfalfa straw on mineral N content, microbial biomass and enzyme activity under controlled conditions. The effect of applying maize straw with alfalfa straw was compared with that of maize straw in combination with N fertilizer under the same C: N ratio (25:1). The laboratory incubation experiment consisted of four treatments: (1) soil with no addition (CK); (2) soil amended with maize straw (M); (3) soil amended with alfalfa straw and maize straw with an adjusted C: N ratio of 25:1 (MM); (4) soil amended with inorganic nitrogen fertilizer and maize straw with an adjusted C:N ratio of 25:1 (MF). The results showed that application of maize straw leaded to an N immobilization during the 270 d of incubation. Combined application of alfalfa and maize straw and or mineral N fertilizer alleviates the N immobilization and increase soil mineral N content. Compared to MF treatment, MM treatment prolonged N availability during the incubation. MM and MF treatments increased the soil microbial biomass carbon and nitrogen contents, and soil invertase and β-glycosidase activities. There was no difference between MM and M treatment in soil urease activity. MF treatment had significantly negative influence on soil urease activity compared with M treatment. The amount of added N significantly affected mineral N content, soil microbial biomass and enzyme activity. The mixture of alfalfa straw and maize straw sustains higher level of mineral N content, microbial biomass and enzyme activity as it had high N input compared to maize straw in combination with N fertilizer. It is concluded that alfalfa straw may be a better N source than N fertilizer in alleviating N immobilization caused by maize straw retention.展开更多
With the objective of obtaining a completely straw-mulched field,when no-tillage mechanical sowing is implemented with straw smashing,delivering,and back-throwing approaches,it may be difficult to scatter the smashed ...With the objective of obtaining a completely straw-mulched field,when no-tillage mechanical sowing is implemented with straw smashing,delivering,and back-throwing approaches,it may be difficult to scatter the smashed straw uniformly during a succeeding wheat sowing step.This is because the previous rice straw is substantial in quantity and has a high humidity and toughness,which may easily result in non-uniform straw mulching and thus sparse and weak seedlings of wheat.Therefore a force-dispersing and uniform-scattering device was designed.With the number of scattering impellers,impeller angle,and impeller rotation speed as the main factors and the percentage of pass for the scattering width and non-uniformity of the straw mulching as the assessment indices,single-factor experiments and orthogonal regressive tests were performed,and a dual-index(percentage of pass for the scattering width and non-uniformity of the straw mulching)fitted regression equation was established.The test results suggested that the main factors(from primary to secondary)that influence the indices were the impeller rotation speed,number of scattering impellers,and impeller angle.The optimal parameter combination for the uniform scattering device was four rows of impellers with an angle of 15°,rotation speed of 1015 r/min,percentage of pass of 72.65%for the scattering width,and a non-uniformity of 13.8%in the straw mulching.This combination can be used to realize a uniform scattering of the smashed straw along the seedling rows on the after-sowing ground.According to the field investigation of the wheat growth,the wheat emergence rate was 90.7%.The research results can provide a reference for improving the uniform scattering device for a straw-smashing,back-throwing,no-tillage planter for obtaining a completely straw-mulched field,enhancing the quality of the machinery operation,and ensuring good and strong seedlings after sowing.展开更多
基金Supported by the National Key Technology R&D Program during the Eleventh Five-year Plan Period,China(2006BAD02A04)the Key Technology R&D Program of Jiangxi Province,China(2009BNA03800)~~
文摘[Objective] To clarify the effects of different straw retention regimes on soil fertility in double cropping paddy field. [Method] The effects of different straw reten- tion regimes on total organic carbon (CToc), active carbon (CA) and mineralized carbon (CM) were analyzed, and carbon pool active (A), carbon pool active index (A/), carbon pool index (CPI) and carbon pool management index (CPMi) for each treat- ment were calculated. [Result] Compared with the unfertilized treatment (CK), CToc, CA, CM and the available ratio of soil carbon were increased in the treatment of re- turning early season and late season rice straws to field. With the same nutrient application, CToc, CA and the available ratio of soil carbon in the field with straw re- turned to field were higher than that of straw incineration and no straw returning, and the change in soil CA content was more significant. The difference in CPMI be- tween different treatments reached significant or very significant level, and the value was in the order of straw directly returned to field 〉 straw returned to field after in- cineration 〉 no straw returned to field. [Conclusion] This study provided theoretical bases for the increase of soil CA content and soil fertility in double rice fields.
基金partially supported by the National Natural Science Foundation of China (31171512)the Central Publicinterest Scientific Institution Basal Research Fund, China (Y2017PT26)
文摘Converting from conventional tillage to no-tillage influences the soil aggregate-size distribution and thus soil organic carbon (SOC) stabilization. However, the dynamics of soil aggregation and the straw-derived carbon (C) incorporation within aggregate fractions are not well understood. An experiment was established in 2004 to test the effects of two treatments, no-tillage with residue (NT) and conventional tillage without residue (CT), on the soil aggregate-size distribution and SOC stabilization in a continuous maize (Zea mays L.) cropping system located in the semiarid region of northern China. Soil samples were collected from the 0-10 cm layer in 2008, 2010 and 2015, and were separated into four aggregate-size classes (〉2, 0.25-2, 0.053-0.25, and 〈0.053 mm) by wet-sieving. In each year, NT soil had a higher proportion of macroaggregates (i.e., 〉2 and 0.25-2 mm) and associated SOC concentration compared with CT. Additionally, to compare straw-derived C incorporation within NT and CT aggregate fractions, ^13C-labeled straw was incubated with intact NT and CT soils. After 90 days, the highest proportion of 13C-labeled straw-derived C was observed in the 〉2 mm fraction, and this proportion was lower in NT than that in CT soil. Overall, we conclude that long-term continuous NT increased the proportion of macroaggregates and the C concentration within macroaggregates, and the physical protection provided by NT is beneficial for soil C sequestration in the continuous maize cropping system in semiarid regions of northern China.
基金the National High-Tech Research and Development Program of China(Grant No.2002AA2Z4331)for generous financial support
文摘A long-term field experiment (started at 2003) was conducted to determine the effects of different dce cultivation methods on growth characteristics and grain yield of late-season rice under double-rice cropping system in seasonal drought region of southeast China (Yujiang County, Jiangxi Province). The rice cultivation methods included no-tillage and flooded rice cultivation (N-F), no-tillage and non-flooded rice cultivation with straw mulching (N-SM), and no-tillage and non-flooded rice cultivation without straw mulching (N-ZM). There was no significant difference in rice grain yield between the N-SM and N-F treatments. However, the rice grain yields in the N-SM and N-F treatments were significantly higher than that in the N-ZM treatment. The late-season rice plants in the N-SM treatment had significantly higher numbers of effective panicles and total grains per hill compared with those in the N-ZM treatment. The above-ground dry matter of late-season rice was similar between the N-SM and N-F treatments. Compared with the N-F treatment, the N-ZM and N-SM treatments significantly decreased the leaf area at the heading stage. Moreover, the N-SM treatment could significantly increase total root length and root tip number at the grain-filling stage compared with the N-ZM treatment.
文摘The various properties of bentonite samples with different sources and their synergistic retention effect with CPAM on wheat straw pulps were investigated. The investigated properties of bentonite included adsorptive capacity based on methylene blue, cation-exchange capacity, swelling volume, colloidal volume, particle size and charge properties. The results show that particle size is the most important properties of bentonite for its synergistic retention effect with CPAM. Using Wyoming type sodium bentonite without drying after modification can obtain the excellent furnishes retention.
文摘In this paper, a new type of retention system of PEO/cofactor retention system is introduced, the cofactors used are phenol-formaldehyde resin, wheat straw alkaline lignin and its derivatives such as hydroxymethylated lignin, sulfited lignin and lignin-based phenol-formaldehyde resin. The first pass retention of newsprint slurry and the properties of handsheet are improved by using the system. The results indicate that a new application field for lignin has been exploited.
基金supported by the National Natural Science Foundation of China(31572460)the Fundamental Research Funds for the Central Universities(lzujbky-2017-ot01)the National Key Research and Development Program of China(2016YFC0400302)
文摘Reduced tillage provides ecological and economic benefits to arable land on the Loess Plateau of China, where soil erosion has long been a serious problem and soil water availability is largely restricted. However, high abundances of weeds in reduced tillage systems cause significant yield losses. In this study, we explored the effects of no-tillage and stubble retention on the number and density of weeds and weed seeds in a 12-year maize-winter wheat-common vetch rotation on the Loess Plateau. Four treatments including conventional tillage, no-tillage, conventional tillage+stubble retention and no-tillage+stubble retention were designed and applied. We found that no-tillage increased the number of weed species and weed density in most of the crops, while stubble retention decreased weed density in maize and tended to suppress weeds in both no-tillage treatments(no-tillage and no-tillage+stubble retention). No-tillage led to an increase in the number of weed species in the weed seedbank and tended to increase seed density during the spring growth of winter wheat, but it decreased seed density during post-vetch fallow. Stubble retention tended to reduce seed density during the spring growth of winter wheat and post-vetch fallow. We concluded that no-tillage can promote weeds in the experimental crop rotation, while stubble retention suppresses weeds in untilled fields. The combined effects of stubble retention and no-tillage on weed suppression varied among the three crops. Based on these results, we recommend stubble retention in untilled legume-crop rotations on the Loess Plateau to improve the control of weeds.
文摘The quality of straw affects N release after straw retention. As straw with high C: N ratio could result in N immobilization, additional N is needed to compensate N demand of crops. However, more and more N fertilizers have been applied to the soil to improve crop yields in China, which not only increases production cost but also reduces soil quality. Therefore, reasonable application of N fertilizer becomes a key problem after straw retention. This study aimed to assess the effects of applying maize straw with high quality alfalfa straw on mineral N content, microbial biomass and enzyme activity under controlled conditions. The effect of applying maize straw with alfalfa straw was compared with that of maize straw in combination with N fertilizer under the same C: N ratio (25:1). The laboratory incubation experiment consisted of four treatments: (1) soil with no addition (CK); (2) soil amended with maize straw (M); (3) soil amended with alfalfa straw and maize straw with an adjusted C: N ratio of 25:1 (MM); (4) soil amended with inorganic nitrogen fertilizer and maize straw with an adjusted C:N ratio of 25:1 (MF). The results showed that application of maize straw leaded to an N immobilization during the 270 d of incubation. Combined application of alfalfa and maize straw and or mineral N fertilizer alleviates the N immobilization and increase soil mineral N content. Compared to MF treatment, MM treatment prolonged N availability during the incubation. MM and MF treatments increased the soil microbial biomass carbon and nitrogen contents, and soil invertase and β-glycosidase activities. There was no difference between MM and M treatment in soil urease activity. MF treatment had significantly negative influence on soil urease activity compared with M treatment. The amount of added N significantly affected mineral N content, soil microbial biomass and enzyme activity. The mixture of alfalfa straw and maize straw sustains higher level of mineral N content, microbial biomass and enzyme activity as it had high N input compared to maize straw in combination with N fertilizer. It is concluded that alfalfa straw may be a better N source than N fertilizer in alleviating N immobilization caused by maize straw retention.
基金This research work is a part of the Special funding project of National Modern Agricultural Peanut Industrial Technology System Construction(CARS-14-mechanical equipment)buried fruit harvester of the innovation project of Chinese Academy of Agricultural Sciences.
文摘With the objective of obtaining a completely straw-mulched field,when no-tillage mechanical sowing is implemented with straw smashing,delivering,and back-throwing approaches,it may be difficult to scatter the smashed straw uniformly during a succeeding wheat sowing step.This is because the previous rice straw is substantial in quantity and has a high humidity and toughness,which may easily result in non-uniform straw mulching and thus sparse and weak seedlings of wheat.Therefore a force-dispersing and uniform-scattering device was designed.With the number of scattering impellers,impeller angle,and impeller rotation speed as the main factors and the percentage of pass for the scattering width and non-uniformity of the straw mulching as the assessment indices,single-factor experiments and orthogonal regressive tests were performed,and a dual-index(percentage of pass for the scattering width and non-uniformity of the straw mulching)fitted regression equation was established.The test results suggested that the main factors(from primary to secondary)that influence the indices were the impeller rotation speed,number of scattering impellers,and impeller angle.The optimal parameter combination for the uniform scattering device was four rows of impellers with an angle of 15°,rotation speed of 1015 r/min,percentage of pass of 72.65%for the scattering width,and a non-uniformity of 13.8%in the straw mulching.This combination can be used to realize a uniform scattering of the smashed straw along the seedling rows on the after-sowing ground.According to the field investigation of the wheat growth,the wheat emergence rate was 90.7%.The research results can provide a reference for improving the uniform scattering device for a straw-smashing,back-throwing,no-tillage planter for obtaining a completely straw-mulched field,enhancing the quality of the machinery operation,and ensuring good and strong seedlings after sowing.