Comprehensive Utilization Policies of Crop Straw at Home and Abroad and Its Implications for Xinjiang

This paper summarizes crop straw utilization policies at abroad from the aspects of investment support policies,tax revenue and unsecured loan policies,and reviewed China s crop straw utilization policies from the aspects of technical training,project subsidies,straw collection,storage and transportation system construction and socialized service system construction.Combined with the actual situation of Xinjiang,this paper puts forward policy formulation suggestions on crop straw comprehensive utilization.

Recommendations for Using Crop Straws to Produce Organic Fertilizers in Liaoning Province

This paper introduces in detail the current situation of crop straw resources and comprehensive utilization in Liaoning Province and the basic situation of enterprises using crop straw to produce organic fertilizers.In addition,it analyzes in detail the problems existing in the production of organic fertilizers in Liaoning Province,and finally comes up with some recommendations for using crop straw to produce organic fertilizers.

Effect of four crop straws on transformation of organic matter during sewage sludge composting

A 45-d laboratory experiment was conducted to compare the effect of four crop straws on the transformations of organic matter （OM） during composting of sewage sludge. The four crop straws included rape straw, wheat straw, maize straw and rice straw. The following parameters such as temperature, OM, humic-like substances （HS）, fulvic-like acids （FA） and humic-like acids （HA） were determined. The degradation of OM and the formation of HS and HA could be described well by the first-order kinetic model, while the FA content fluctuated during composting. The maximal degradation rates of OM in the compost piles added with rape straw, wheat straw, maize straw and rice straw were 34.7, 46.9, 54.7 and 52.8%, respectively, and the final contents of HS were 118, 128, 141 and 134 g kg-1, respectively, while the humification indices were higher in the compost piles added with maize straw and wheat straw than in those with rice straw and rape straw. The results indicate that a higher hemicellulose content and a lower C/N ratio in crop straw can result in a higher rate of OM degradation and higher contents of HS, while a higher content of lignin can lead to a higher polymerization degree of humic substances in compost piles. The final compost piles added with maize straw has the highest contents of OM, total nitrogen and humus substance as well as the highest values of polymerization degree, while compost piles with rape straw have the highest potassium content and those with rice straw have the highest pH values.

Effects of different long-term crop straw management practices on ammonia volatilization from subtropical calcareous agricultural soil

Ammonia(NH3)volatilized from agricultural production and its secondary aerosols contribute greatly to air pollution.Different long-term crop straw management practices may significantly affect the soil fertility and soil nitrogen cycle,however,the effect on NH3 volatilization has not been well studied.Therefore,a one-year field experiment was conducted to evaluate the effect of straw incorporation on NH3 volatilization from subtropical calcareous agricultural soil from a longterm perspective,including four treatments:synthetic fertilizer(CK);synthetic fertilizer incorporation with 100%or 50%of the previous season’s crop straw(SI1 and SI2,respectively);and synthetic fertilizer incorporation with 50%burned crop straw(SI2B).Soil NH3 volatilizations were monitored through a wheat–maize rotation year by using a dynamic chamber method.The results demonstrated that NH3 volatilization primarily occurred within 38 days and 7–10 days following nitrogen fertilization events for the wheat and maize seasons,respectively.Different crop straw management practices mainly impacted the NH3 flux of the basal fertilization rather than the topdressing fertilization;long-term crop straw incorporation effectively lowered NH3 loss(35.1%for SI1 and 16.1%for SI2 compared to CK;and the inhibiting effect increased with increasing straw amount,possibly contributed by the high straw carbon/nitrogen ratio,and enhanced microbial activity,which contributed to inorganic nitrogen immobilization and lower ammonium content in the topsoil.However,SI2B significantly increased(29.9%)the annual NH3 flux compared with SI2,indicating that long-term 100%straw incorporation could be a promising straw management practice for mitigating NH3 loss and increasing soil fertility.

Effect of Garlic Straw on Physical and Chemical Characteristics of Continuous Cropping Soil and Root Activity of Tomato in Solar Greenhouse

Taking tomato ＂Kate two＂ as the experimental material, the effects of different dosage of garlic straw on physical and chemical characteristics of continuous cropping soil and root activity of tomato in solar greenhouse were studied. The results showed that after applying with garlic straw, maximal and minimal temperatures in 0-15 cm soil layers were directly proportional to the amount of returned garlic straw, which were 2.39 ℃ and 1℃ higher than that of the control respectively. The unit weight was decreasing upon the amount of applied garlic straws of soils in different depths, but the porosity of soil was increasing. For example, unit weight and porosity changed the most significantly in soils in the depths of 0-10 cm, which went down by 6.71% and 6.18%, respectively. Besides, garlic straw returning to field improved soil pH, reduced soil conductivity and soil acidification and relieved soil secondary salinization, especially in 0-20 cm soil layers. In addition to that, the application of garlic straw increased the root activity of tomato （max 31.45%）, and delayed root system senescence in late stage. Therefore, garlic straw returning could improve the physical and chemical characteristics of soil by succession planting and root activity of tomato in solar greenhouse.

Current Situation and Countermeasures of Utilization of Crop Straw as Feed in Sichuan Province

Utilizing straw as feed and applying cattle and sheep manure fertilizer to the field plays an important role in solving the shortage of feed raw material resources,alleviating the conflict between human beings and livestock,and realizing the full utilization of straw as a resource and green and low-carbon circular development.We carried out an investigation on the feed utilization of crop straw in Sichuan Province,comprehensively grasped the crop straw resources and its utilization as feed in this province,deeply analyzed the existing problems,and put forward countermeasures and suggestions according to the actual situation in Sichuan,which plays an important role in accelerating the process of straw feed utilization,promoting green development,implementing the rural revitalization strategy,and building a beautiful Sichuan.

A Mode Research of Straw Recycling Based on Circular Agriculture Theory

Recycling of crop residues resources has become an urgent problem to be addressed in agriculture and rural areas of China.Compared to single use patterns of crop residues resources,crop residues circular agriculture characterized by multi-grade utilization and recycling is more important to improve the added value of crop residues,to enhance product market competitiveness,and to promote scale development and industrialization of crop residues recycling.This paper discussed the basic principles of the development of crop residues circular agriculture mode,and summarized five main crop residues circular agriculture mode.

Dynamics of microbial diversity during the composting of agricultural straw

The dynamic changes in microbial diversity during the aerobic composting of agricultural crop straw with additives were evaluated using high-throughput sequencing at four phases of composting(mesophilic,thermophilic,cooling and maturation phases).In addition,the physicochemical parameters of the composting system were determined in this study.The fermentation time of the thermophilic period was prolonged with the addition of urea or urea combined with a microbial agent.The ratio of C/N and germination index variation indicated that the additives were favorable for composting,because the additives directly changed the physicochemical properties of the compost and had effects on the diversity and abundance of bacteria and fungi.The abundance of operational taxonomic units(OTUs),diversity index(Shannon)and richness index(Chao1)of fungi and bacteria were found to significantly increase when urea+microbial agents were added to straw in the thermophilic phase.The relative abundance of the predominant bacteria and fungi at the phylum and genus levels differed during different composting phases.The abundance of the phyla Firmicutes and Proteobacteria declined in the order of treatments SNW>SN>S(S is straw only compost;SN is straw+5 kg t^(–1) urea compost;and SNW is straw+5 kg t^(–1) urea+1 kg t^(–1) microbial agent compost)in the thermophilic phase.The abundance of the genera Staphylococcus,Bacillus and Thermobifida followed the same order in the mesophilic phase.Ascomycota accounted for more than 92%of the total fungal sequences.With the progression of the composting process,the abundance of Ascomycota decreased gradually.The abundance of Ascomycota followed the order of S>SN>SNW during the thermophilic phase.The abundance of Aspergillus accounted for 4–59%of the total abundance of fungi and increased during the first two sampling periods.Aspergillus abundance followed the order of SNW>SN>S.Additionally,principal component analysis(PCA)revealed that the community compositions in the straw and straw+urea treatments were similar,and that the bacterial communities in treatments S,SN and SNW in the mesophilic phase(at day 1)were different from those observed in three other phases(at days 5,11,and19,respectively),while the fungal communities showed only slight variations in their structure in response to changes in the composting process.Canonical correlation analysis(CCA)and redundancy analysis(RDA)showed that total carbon(TC),NO_(3)^(–)-N(NN),electrical conductivity(EC)and p H were highly correlated with community composition.Therefore,this study highlights that the additives are beneficial to straw composting and result in good quality compost.

Enhancement of Cd Solubility and Bioavailability Induced by Straw Incorporation in Cd-Polluted Rice Soil

Of the factors affecting migration and bioavailability of toxic metals in heavy metal contaminated soil, DOC （dissolved organic carbon） provides binding sites for metal cations and reduces the fixation and adsorption of heavy metals by soil solid phase. Elevation of DOC level due to the direct incorporation of crop residues may lead to enhanced accumulation of toxic metals in crop body grown in polluted farmland. In this study, an incubation experiment and a pot experiment were conducted respectively to investigate the effects of wheat straw incorporation on DOC level, cadmium availability, and Cd accumulation in rice plant, and to establish the relation between Cd solubility and DOC level. A Cd-contaminated rice soil was used and incorporated with different rates （0%, 0.5% and 1%） of wheat straw in both experiments. Results showed that the change pattern of Cd in soil solution was very similar to that of DOC level. Wheat straw addition significantly elevated Cd and DOC level in soil solution while NH4NO3-extrated Cd was not affected. There existed a close linear correlation between soluble Cd and DOC level. Enhanced Cd accumulation in rice plant, grown in a Cd contaminated soil, induced by wheat straw incorporation was observed in this study.

The effects of straw‑returning and inorganic K fertilizer on the carbon–nitrogen balance and reproductive growth of cotton

Background:Many studies have indicated that straw-returning could meet part or even all of the potassium(K)demand for crop growth in the field,but few have compared the effects of crop straw as K source and inorganic K fertilizer on carbon–nitrogen(C–N)balance of cotton and the reproductive growth.To address this,field experiments were conducted using the cotton cultivar,Siza 3,under there treatments(CK as control group one,no crop straw and inorganic K fertilizer were applied;K150 as control group two,150 kg·ha^(-1) of K2O was applied;and W9000,9000 kg·ha^(-1) wheat straw,which could provide K2O about 150 kg·ha^(-1),was incorporated into soil).Results:Although the final reproductive organ biomass did not differ between W9000 and K150,W9000 had a higher ratio of reproductive organ biomass to total biomass(RRT),suggesting that straw-returning was more conducive to the allocation of biomass to reproductive organs.The theoretical maximum biomass of reproductive organ was higher,but the average and maximum accumulation rates of reproductive organ biomass were 2.8%∼8.3%and 2.5%∼8.2%lower under W9000 than K150.Also,the duration of rapid-accumulation period for reproductive organ biomass(T)was 2.0∼2.8 d longer under W9000 than K150,which was a reason for the higher RRT under W9000.Straw-returning altered the dynamics of leaf K with the growth period,so that W9000 had a more drastic effect on leaf C metabolism than K150.Consequently,lower soluble sugar/free amino acid and C/N ratios were measured under W9000 than K150 at boll-setting(BSS)and boll-opening(BOS)stages.Higher leaf net photosynthetic rate,sucrose phosphate synthase and sucrose synthase activities,and lower acid invertase activity were observed under W9000 than K150 at BSS and BOS and these were more conducive to sucrose accumulation.However,less sucrose was measured under W9000 than K150 at these stages.This should be because straw-returning promoted the assimilate transport capacity when compared with inorganic K fertilizer application,which also explained the higher RRT under W9000 than K150.The lower acid invertase activity under W9000 inhibited the conversion of sucrose to other sugars,hence lower contents of soluble sugar and starch were measured under W9000 than K150.Conclusion:Under low K condition,crop straw as K source can increase the assimilate transport from source to sink,leading to lower C/N ratio in leaf and higher allocation of biomass to reproductive organs than inorganic K fertilizer.

基于MODIS的秸秆焚烧火点识别原理及算法IDL实现

秸秆焚烧容易污染空气,影响交通。常规秸秆焚烧监测难度较大,而卫星遥感数据具有覆盖面广,时效性强、分辨率高等优点,有利于秸秆焚烧监测工作的进展。本文将介绍如何使用MODIS数据提取秸秆焚烧火点的算法。在算法实现上采用交互式数据语言IDL(Interactive Data Language)进行实现,大大缩短了人机交互时间,提高了秸秆焚烧点自动提取的响应速度,从而提高工作效率,促进秸秆焚烧监测工作的开展。

利用改进型MODIS火点探测算法实现河北省秸秆焚烧火点识别

为准确地了解河北省秸秆焚烧火点的空间分布,为秸秆焚烧监测的实现、禁烧工作的开展、环境质量改善提供支持.基于MODIS L1B数据、MODIS标准火点产品MOD14、全国秸秆焚烧火点日报数据为基础,采用改进型MODIS火灾探测算法,并通过IDL语言实现,得到秸秆焚烧火点空间分布信息,并进行空间与定量精度分析.研究表明:火点大部分位于河北省南部的一些地区,其中尤以邢台、石家庄、邯郸火点数量最为突出;该算法运算速度快,获取的秸秆焚烧火点数据具有一定检测精度和可靠性,对秸秆焚烧的监测具有一定的实用价值.

Adsorption of Cr(Ⅲ) from acidic solutions by crop straw derived biochars

Cr（Ⅲ） adsorption by biochars generated from peanut, soybean, canola and rice straws is investigated with batch methods. Adsorption of Cr（Ⅲ） increased as pH rose from 2.5 to 5.0. Adsorption of Cr（Ⅲ） led to peak position shifts in the FFIR-PAS spectra of the biochars and made zeta potential values less negative, suggesting the formation of surface complexes between Cr^3＋ and functional groups on the biochars. The adsorption capacity of Cr（Ⅲ） followed the order： peanut straw char 〉 soybean straw char 〉 canola straw char 〉 rice straw char, which was consistent with the content of acidic functional groups on the biochars. The increase in Cr^3＋ hydrolysis as the pH rose was one of the main reasons for the increased adsorption of Cr（Ⅲ） by the biochars at higher pH values. Cr（llI） can be adsorbed by the biochars through electrostatic attraction between negative surfaces and Cr^3＋, but the relative contribution of electrostatic adsorption was less than 5%. Therefore, Cr（Ⅲ） was mainly adsorbed by the biochars through specific adsorption. The Langumir and Freundlich equations fitted the adsorption isotherms well and can therefore be used to describe the adsorption behavior of Cr（Ⅲ） by the crop straw biochars. The crop straw biochars have great adsorption capacities for Cr（Ⅲ） under acidic conditions and can be used as adsorbents to remove Cr（Ⅲ） from acidic wastewaters.

Changes of Organic Matter, N, P and K Content of Soils in Red Soil Areas Under Long-Term Experiment

The content of organic matter （OM）, nitrogen （N）, phosphorus （P）, and potassium （K） in the three selected soils, including Calcaric Purpli-Orthic Primosols （purple sand-shale parent material）, Dystric Turbi-Anthric Primosols （quaternary red clay parent material） and Typic Udi-Sandic Primosols （granite parent material） were studied under a long-term experiment by using crop straw and inorganic fertilizers at the Hunan Red Soil Experiment Station of Chinese Academy of Agricultural Sciences. The results showed that the contents of OM, N, P and K in the three selected soils increased after 23 years application of crop straw and inorganic fertilizers, but the contents increased much less when crop straw or inorganic fertilizers was applied alone. The nutrient contents in the three soils developed from granite changed more remarkably than those in the soil derived from quaternary red clay and purple sand-shale. It was also found that the contents of OM, N, and P increased slightly in the treatments without applying fertilizers or returning the crop straw to the root bed. Combined application of inorganic fertilizers and crop straw could remarkably increase the contents of OM, alkalihydrolyzable N and available K, the positive correlation between application of organic fertilizers and increase of OM in soil did not always happened, it provided evidence for the relation between appropriate C/N ratio and accumulation of OM in soil. The increase of nutrient content was influenced by the soil properties. By comparing the contents of nutrient in 0-20 cm depth in the three different soils, it was concluded that the most increases of OM, alkali-hydrolyzable N, and available P were observed in Typic Udi-Sandic Primosols with the average increase by 3.03, 27.38, and 21.73 mg kg^-1, respectively. The available K increased in Dystric Turbi-Anthric Primosols with the average increase by 25.82 mg kg^-1, while it decreased in Calcaric Purpli-Orthic Primosols and Typic Udi-Sandic Primosols. It was concluded that the application of inorganic fertilizer and crop straw was important to improve the soil fertility for all of three selected soils. The straw return to the field had played a significant role for enhancement of the soil quality in the study areas. The application of inorganic fertilizer combined with the straw return to the fields could remarkably improve the soil fertility.

秸秆焚烧对区域城市空气质量影响的模拟分析

利用融合火点排放源、人为源和生物源的WRF-Chem(Weather Research and Forecasting Model coupled with Chemistry)模式,模拟2015年9月30日08:00(北京时间)起的72 h发生在淮河流域的一次农作物秸秆大面积露天焚烧过程,研究了农作物秸秆焚烧释放的气态污染物和颗粒物对区域城市空气质量的影响。通过有无火点两组试验分析了此次秸秆焚烧对流域内河南、山东、江苏和安徽四省83座城市CO、PM10(空气动力学当量直径小于等于10μm的颗粒物,即可吸入颗粒物)、PM2.5(空气动力学当量直径小于等于2.5μm的颗粒物,即细颗粒物)和O3浓度的定量影响,结果表明:(1)融合NCAR-FINN(Fire Inventory from NCAR)火点排放资料的WRF-Chem模式较好地再现了此次秸秆焚烧及火点烟羽扩散过程。同时结合EDGAR-HTAP(Emission Database for Global Atmospheric Research on Hemispheric Transport of Air Pollution)人为源和MEGAN(Model of Emission of Gases and Aerosols from Nature)生物源的WRF-FIRE(考虑火点排放试验)对流域内城市大气污染物的模拟效果较为理想,尤其对秸秆焚烧释放的污染物CO、PM10和PM2.5和产生的二次污染物O3浓度的模拟。(2)秸秆焚烧所释放的污染物造成流域内城市一次污染物CO、PM10和PM2.5浓度的增加,火点中心和下风向城市增幅最为明显,最大小时浓度增幅达到3倍标准差。气态污染物CO和相比PM10粒径更小的PM2.5可随风扩散至更远的地区,对城市浓度影响更大。(3)此外,秸秆焚烧也使得火点中心城市和下风向城市二次污染物O3浓度增加,但小时浓度增幅极值区分布在火点下风向烟羽末端太阳光照充足的地区,最大小时浓度增幅接近3倍标准差。秸秆焚烧对区域城市空气质量的影响存在明显的空间分布差异且对城市各大气污染成分的影响也不相同。

Online single particle analysis of chemical composition and mixing state of crop straw burning particles： from laboratory study to field measurement

Fresh straw burning （SB） particles were generated in the laboratory by the combustion of rice straw and corn straw. The chemical composition and mixing state of the fresh SB particles were investigated by an Aerosol Time-of-Flight Mass Spectrometer （ATOFMS）. Based on the mass spectral patterns, the SB particles were clustered into four major types： Salt, Organic Carbon （OC）, Elemental Carbon （EC）, and internally mixed particles of EC and OC （EC-OC）. In addition, particles containing ash, polycyclic aromatic hydrocarbons, heavy metals or nicotine were also observed. Physical and chemical changes of the SB particles immediately after the emission were analyzed with highly time-resolved data. During the aging processes, the average particle size increased steadily. Freshly emitted organic compounds were gradu- ally oxidized to more oxygenated compounds in the OC- containing particles. Meanwhile, an important displace- ment reaction （2KCI＋ SO24- KzSO4 ＋ 2C1-） was observed. The marker ions for SB particles were optimized and applied to identify the SB particles in the ambient atmosphere. The fluctuation of the number fraction of ambient SB particles sorted by ATOFMS agrees well with that of water soluble K＋ measured by an online ion chromatography, demonstrating that the optimized marker ions could be good tracers for SB particles in field measurements.

秸秆电厂的火灾风险分析与防范

分析秸秆电厂的流程工艺特性和潜在火灾风险,包括粉尘爆炸、堆垛火灾和原料预处理过程火灾等。从防止事故发生、减轻和降低事故发生的程度与后果、及时扑灭初期火灾的角度,结合燃煤电厂和粮食企业防火设计实践与秸秆燃料本身特性,提出了有针对性的应对措施与原则。

Evaluation of different clean heat supply modes based on crop straws in the rural area of Northern China

This study evaluated eight different types of heat supply modes based on crop residues utilization in the rural area of Northern China,including straw densified solid fuel combustion,pyrolysis char combustion,biogas combustion,and pyrolysis gas combustion for single household heating;straw densified solid fuel combustion,baling straw combustion,biogas combustion,and pyrolysis gas combustion for centralized heating;centralized gas supply and centralized pyrolysis gas supply modes.Comprehensively evaluation was the cost of these different eight heat supply modes.The results showed that the cost of straw densified solid fuel combustion,pyrolysis char combustion for single household heating were 2346 RMB/household and 2390 RMB/household.With the heating scale of 200-500 households,the pipe network distance was 8 m/household,and the total annual heating cost was predicted at 2201-2992 RMB/household.Among them,the cost of straw baling combustion for centralized heating was the lowest,the cost of densified solid fuel,biogas,and pyrolysis for centralized heating was the second,and the cost of biogas and pyrolysis gas for centralized gas supply was the highest.For the increase in every 1 m of the pipeline distance,the investment cost will increase by about 645 RMB for each household.This study provides a basis for the implementation of clean heat supply technologies in less-developed areas and guidance of village heat-supply subsidy policies.

生物质秸秆捆包直燃蒸汽锅炉应用于粮食烘干的研究

粮食烘干用生物质秸秆捆包直燃蒸汽锅炉,以农作物秸秆捆包为燃料,用于取代原粮食收储企业燃煤热风炉,投资少、见效快、也符合国家政策导向。该锅炉不仅适用于建成区外和乡镇所在地的粮食收储企业进行粮食烘干,还适用于建成区内的粮食收储企业及附近居民和其他企事单位进行供汽和供暖,更适用于广大供热企业对用汽、用热单位和居民进行能源管理。将生物质秸秆锅(窑)炉的灰渣,与畜、禽粪便进行混合、发酵制作成有机复合肥回归到黑土地。这样,就能使农作物秸秆变废为能、变废为宝,从而彻底解决农作物秸秆的露天焚烧问题,真正把打赢“蓝天保卫战”落到实处。

Emissions of parent, nitrated, and oxygenated polycyclic aromatic hydrocarbons from indoor corn straw burning in normal and controlled combustion conditions

Emission factors （EFs） of parent polycyclic aromatic hydrocarbons （pPAHs）, nitrated PAHs （nPAHs）, and oxygenated PAHs （oPAHs） were measured for indoor corn straw burned in a brick cooking stove under different burning conditions. The EFs of total 28 pPAHs, 6 nPAHs and 4 oPAHs were （7.9 ±3.4）, （6.5 ±1.6）×10^-3, and （6.1 ±1.4）×10^-1mg/kg, respectively. Fuel charge size had insignificant influence on the pollutant emissions. Measured EFs increased significantly in a fast burning due to the oxygen deficient atmosphere formed in the stove chamber. In both restricted and enhanced air supply conditions, the EFs of pPAHs, nPAHs and oPAHs were significantly higher than those measured in normal burning conditions. Though EFs varied among different burning conditions, the composition profiles and calculated isomer ratios were similar, without significant differences. The results from the stepwise regression model showed that fuel burning rate, air supply amount, and modified combustion efficiency were the three most significant influencing factors, explaining 72%-85% of the total variations.