In-field management of corn cob and residue mix: Effect on soil greenhouse gas emissions     

《Applied soil ecology》2015

In-field management practices of corn cob and residue mix (CRM) as a feedstock source for ethanol production can have potential effects on soil greenhouse gas (GHG) emissions. The objective of this study was to investigate the effects of CRM piles, storage in-field, and subsequent removal on soil CO₂ and N₂O emissions. The study was conducted in 2010–2012 at the Iowa State University, Agronomy Research Farm located near Ames, Iowa (42.0°′N; 93.8°′W). The soil type at the site is Canisteo silty clay loam (fine-loamy, mixed, superactive, calcareous, mesic Typic Endoaquolls). The treatments for CRM consisted of control (no CRM applied and no residue removed after harvest), early spring complete removal (CR) of CRM after application of 7.5 cm depth of CRM in the fall, 2.5 cm, and 7.5 cm depth of CRM over two tillage systems of no-till (NT) and conventional tillage (CT) and three N rates (0, 180, and 270 kg N ha⁻¹) of 32% liquid UAN (NH₄NO₃) in a randomized complete block design with split–split arrangements. The findings of the study suggest that soil CO₂ and N₂O emissions were affected by tillage, CRM treatments, and N rates. Most N₂O and CO₂ emissions peaks occurred as soil moisture or temperature increased with increase precipitation or air temperature. However, soil CO₂ emissions were increased as the CRM amount increased. On the other hand, soil N₂O emissions increased with high level of CRM as N rate increased. Also, it was observed that NT with 7.5 cm CRM produced higher CO₂ emissions in drought condition as compared to CT. Additionally, no differences in N₂O emissions were observed due to tillage system. In general, dry soil conditions caused a reduction in both CO₂ and N₂O emissions across all tillage, CRM treatments, and N rates.  相似文献   

Impact of different crop rotations and tillage systems on weed infestation and productivity of bread wheat     

《Crop Protection》2016

Crop rotation and tillage systems have important implications for weed infestation and crop productivity. In this study, five tillage systems viz. zero tillage (ZT), conventional tillage (CT), deep tillage (DT), bed sowing (60/30 cm with four rows; BS₁) and bed sowing (90/45 cm with six rows; BS₂) were evaluated in five different crop rotations viz. fallow-wheat (FW), rice-wheat (RW), cotton-wheat (CW), mungbean-wheat (MW) and sorghum-wheat (SW) for their effect on weed infestation and productivity of bread wheat. Interaction between different tillage practices and cropping systems had significant effect on density and dry biomass of total, broadleaved and grass weeds, agronomic and yield-related traits, and grain yield of bread wheat. The un-disturbed soils (ZT) under fallow-wheat or mungbean-wheat rotations favoured the weed prevalence (a total weed dry biomass of 72.4–109.6 and 105.6–112.1 g m⁻² in first and second year, respectively). Contrary to this, the disturbed soils (CT, DT, BS₁ and BS₂) had less weed infestation with either of the rotations (a total weed biomass of 0.4–7.1 and 1.1–5.4 g m⁻² in first and second year, respectively). Sorghum-wheat rotation had strong suppressive effect on weed infestation in all tillage systems. The impact of crop rotation was more visible during second year of experimentation. Bed sown wheat (BS₁ and BS₂) in mungbean-wheat rotation had the highest wheat grain yield (6.30–6.47 t ha⁻¹) compared to other tillage systems in different crop rotation combinations.  相似文献   

脲酶/硝化抑制剂配施氮肥对春玉米农田氨排放的影响     

王甄烨  焉莉  蒋富琛  田洪涛  王少杰  高强  冯国忠 《玉米科学》2022,30(1):138-143

通过两年田间定位试验,探讨脲酶/硝化抑制剂配施氮肥在黑土区玉米体系中的氨减排及氮素增效效果。设置两种耕作模式(条耕和旋耕)和3种氮肥类型(常规尿素、添加脲酶抑制剂尿素、添加硝化抑制剂尿素)。结果表明,条耕产量和氮素利用率分别为8 631 kg/hm2和33.4%,明显低于旋耕;氨挥发总量为20.6 kg/hm2,明显高于旋耕。脲酶/硝化抑制剂配施氮肥的产量和氮素利用率分别为10 737 kg/hm2和46.0%,较常规尿素分别提高25.6%和23.6%;土壤氨挥发累积量为18.6 kg/hm2,明显低于常规尿素。抑制剂类型显著影响氨排放,添加脲酶抑制剂尿素低于添加硝化抑制剂尿素。相同氮素投入条件下,添加脲酶/硝化抑制剂尿素在土壤条耕和旋耕模式下均可实现增产增效及氨减排效果,且添加脲酶抑制剂尿素具有较好的氨减排效果。  相似文献   

Land-use history has a stronger impact on soil microbial community composition than aboveground vegetation and soil properties     

Kamlesh Jangid  Mark A. Williams  Thomas M. Schmidt  William B. Whitman 《Soil biology & biochemistry》2011,43(10):2184-2193

The response of soil microbial communities following changes in land-use is governed by multiple factors. The objectives of this study were to investigate (i) whether soil microbial communities track the changes in aboveground vegetation during succession; and (ii) whether microbial communities return to their native state over time. Two successional gradients with different vegetation were studied at the W. K. Kellogg Biological Station, Michigan. The first gradient comprised a conventionally tilled cropland (CT), mid-succession forest (SF) abandoned from cultivation prior to 1951, and native deciduous forest (DF). The second gradient comprised the CT cropland, early-succession grassland (ES) restored in 1989, and long-term mowed grassland (MG). With succession, the total microbial PLFAs and soil microbial biomass C consistently increased in both gradients. While bacterial rRNA gene diversity remained unchanged, the abundance and composition of many bacterial phyla changed significantly. Moreover, microbial communities in the relatively pristine DF and MG soils were very similar despite major differences in soil properties and vegetation. After >50 years of succession, and despite different vegetation, microbial communities in SF were more similar to those in mature DF than in CT. In contrast, even after 17 years of succession, microbial communities in ES were more similar to CT than endpoint MG despite very different vegetation between CT and ES. This result suggested a lasting impact of cultivation history on the soil microbial community. With conversion of deciduous to conifer forest (CF), there was a significant change in multiple soil properties that correlated with changes in microbial biomass, rRNA gene diversity and community composition. In conclusion, history of land-use was a stronger determinant of the composition of microbial communities than vegetation and soil properties. Further, microbial communities in disturbed soils apparently return to their native state with time.  相似文献   

耕作措施对温带半干旱地区土壤温室气体(CO₂、CH₄、N₂O)通量的影响   总被引：3，自引：1，他引：3  

汪婧  蔡立群  张仁陟  王友玲  董稳军 《中国生态农业学报》2011,19(6):1295-1300

通过设置在甘肃省定西市李家堡镇的不同耕作措施试验, 利用CO₂分析仪、静态箱-气相色谱法对双序列轮作次序下春小麦地、豌豆地生育期内CO₂、CH₄和N₂O通量进行了测定。试验结果表明: 4种耕作措施下春小麦地和豌豆地在生育期内均表现为CO₂源、N₂O源和CH₄汇的功能。传统耕作不覆盖、免耕不覆盖、免耕秸秆覆盖和传统耕作结合秸秆还田下, 春小麦生育期内平均土壤CO₂通量(μmol·m^-2·s^-1)分别为0.203 6、0.221 2、0.241 8、0.224 9, CH₄通量(mg·m^-2·h^-1)分别为-0.041 6、-0.078 0、-0.081 8、-0.053 7, N₂O通量(mg·m^-2·h^-1)分别为0.089 1、0.069 2、0.046 1、0.065 6; 豌豆生育期内平均土壤CO₂通量(μmol·m^-2·s^-1)分别为0.273 6、0.261 6、0.218 1、0.236 0, CH₄通量(mg·m^-2·h^-1)分别为-0.055 0、-0.073 7、-0.066 2、-0.054 5, N₂O通量(mg·m^-2·h^-1)分别为0.123 4、0.084 7、0.080 6、0.035 0。少免耕及小麦秸秆覆盖有利于减少土壤CO₂排放通量, 免耕不覆盖、免耕秸秆覆盖及传统耕作结合秸秆还田均能不同程度地增加CH₄吸收通量、减少N₂O排放通量。综合来看, 免耕不覆盖、免耕秸秆覆盖和传统耕作结合秸秆还田3种保护性耕作措施有助于减少土壤温室气体的排放量。春小麦地CO₂通量随着土壤温度、土壤含水量的逐渐升高而增大; CH₄吸收通量随着土壤含水量的逐渐升高而增大, 而随着土壤温度的逐渐升高而减小。豌豆地CO₂通量的变化与土壤含水量存在极显著正相关关系; 而春小麦地N₂O通量则与平均土壤温度呈显著正相关, 豌豆地则为极显著正相关。  相似文献   

土壤容重对玉米光合特性的影响及调控研究   总被引：3，自引：0，他引：3  

郑存德  依艳丽 《土壤学报》2012,49(5):944-953

以耕地棕壤为试验材料,采用盆栽方法,研究不同土壤容重对玉米光合指标(光合速率、气孔导度、胞间二氧化碳浓度)及叶绿素(a、b)的影响,并进一步研究了施用不同有机肥量及模拟不同耕作深度对玉米光合指标的调控效果。结果表明:不同容重处理之间对玉米叶绿素含量的影响拔节期前差异不显著,拔节期后达极显著差异(p<0.01),叶绿素含量在研究的生育期内始终增长。光合速率与容重、胞间二氧化碳浓度呈负相关,与气孔导度呈正相关。高容重土壤有机质调节至40～50 g kg-1即可以获得比较理想的效果;低容重的土壤有机质在研究含量范围内效果始终显著增长,有机质含量在15 g kg-1左右制约玉米生长,有机质含量应至少调节至3%以上。耕层厚度增加能提高所测定生理指标,但耕层厚度处理对叶绿素、光合指标影响不显著,当耕层厚度调节至30～40 cm时,各项指标增加基本达到限值,再增加耕层厚度作用不再明显。  相似文献   

耕作方式对华北冬小麦.夏玉米周年产量和水分利用的影响   总被引：7，自引：1，他引：7  

孔凡磊  张海林  翟云龙  袁继超  陈阜 《中国生态农业学报》2014,22(7):749-756

在冬小麦季设置秸秆不还田翻耕(CT)、秸秆还田翻耕(CTS)、秸秆还田旋耕(RTS)和免耕秸秆覆盖(NTS)4种处理,研究耕作方式对华北小麦-玉米两熟区作物周年产量和水分利用的影响。结果表明:耕作方式对当季冬小麦产量和水分利用影响显著,对夏玉米产量和水分利用影响不大,但秸秆还田提高了夏玉米产量。RTS、CTS、CT 3个处理小麦季产量差异不显著,而NTS由于有效穗数不足,产量显著低于其他处理;与CT相比,NTS周年产量平均减产5.13%,RTS增产2.69%,CTS增产2.33%。耕作方式对当季小麦土壤水分含量影响大,而对后茬夏玉米土壤水分含量的影响较小。NTS提高了小麦季土壤水分含量,增加了土壤储水量,与CT相比,0~60 cm土壤储水量2010年和2011年分别增加39.07 mm和26.65 mm。从耗水构成来看,土壤水在冬小麦耗水中所占比例最大,其次为灌水和降水;而夏玉米耗水以降水为主,且降水中有一部分转化为土壤水储存起来。NTS提高了冬小麦季土壤储水量,降低了土壤水分的消耗,冬小麦季耗水最少。与CT相比,NTS小麦季平均节水22.40 mm,周年耗水量也以NTS最少;但NTS冬小麦产量降低导致其小麦季和周年水分利用效率均最低。从作物周年产量和水分利用的角度来看,如何提高免耕秸秆覆盖小麦季产量,进而提高周年产量,发挥其节水优势,是该耕作模式在华北地区冬小麦?夏玉米两熟区推广应用亟需解决的关键问题。  相似文献   

不同耕作条件下豆麦双序列轮作农田土壤温室气体的排放及影响因素研究   总被引：2，自引：0，他引：2  

蔡立群  王娟  罗珠珠  武均  张仁陟 《中国生态农业学报》2013,21(8):921-930

为了研究耕作措施对双序列轮作农田土壤温室气体的排放及影响, 采用CO₂分析仪、静态箱 气相色谱法在陇中黄土高原半干旱区对传统耕作不覆盖、免耕不覆盖、免耕秸秆覆盖和传统耕作+秸秆还田4种耕作措施下豆麦双序列轮作农田土壤温室气体(CO₂、N₂O和CH₄)的排放及影响因素进行了连续测定和分析。结果表明: 测定期内4种耕作措施下农田土壤均表现为CO₂源、N₂O源和CH₄净吸收汇; 除传统耕作不覆盖措施, 其他3种耕作措施不同程度地减少了2种轮作序列土壤的N₂O排放通量, 并显著增加了土壤对CH4的吸收。CO₂和N₂O的排放通量分别与地表、地下5 cm处、地下10 cm处的土壤温度呈极显著和显著正相关关系, 相关系数分别为0.92^**和0.89^**、0.95^**和0.91^**、0.77^*和0.62^*; 而CH₄吸收通量与不同地层的温度之间无明显的相关关系; CO₂和CH₄的通量与0~5 cm、5~10 cm的土壤含水量均呈显著正相关关系, 相关系数分别为0.69^*和0.72^*、0.77^*和0.64^*, 而与10~30 cm土壤含水量无明显相关关系; N₂O排放通量与各层次的土壤含水量之间均呈不显著负相关关系。对2种轮作序列各处理下土壤中排放的3种温室气体的增温潜势计算综合得出: 4种耕作措施中, 免耕不覆盖处理可相对减少土壤温室气体的排放量, 进而降低温室效应。  相似文献   

不同类型耕地紫色土中3,5,6-三氯-2-吡啶醇迁移试验与模拟     

雷文娟  唐翔宇  关卓  周向阳  王秉玺  张维 《农业工程学报》2015,31(5):132-138

3,5,6-三氯-2-吡啶醇(TCP)的化学结构稳定、水溶性高、运移能力强,对水体具有潜在的污染风险。在有机质含量低、大孔隙度高、导水性好的紫色土地区,风险更加显著。为研究TCP在紫色中的迁移规律,该研究依据紫色土的典型耕作类型,在中国科学院盐亭国家紫色土农业生态试验站采集3组土样(小麦-玉米轮作的坡地、水稻-油菜轮作的水旱农田和萝卜-白菜套种的菜地),通过批量平衡法研究紫色土对TCP的吸附特征,并采用稳定流场饱和均质土柱的易混合置换试验研究TCP的动态迁移过程,最后对其迁移动态进行模拟。结果表明:紫色土对TCP的吸附特征呈线性,在坡地、水旱农田和菜地中的吸附系数分别为1.94、1.22和1.02 L/kg,且黏土含量和矿物组成是主要影响因子;TCP的出流平衡浓度分别为初始浓度的77%(坡地)、84%(水旱农田)和92%(菜地),相应的平衡时刻分别为2.88PV、4PV和6.5PV,表明TCP对环境的污染风险较高;用非平衡两点对流弥散模型模拟TCP在3种耕作条件下迁移,表明TCP以瞬时吸附为主,其水动力弥散系数和分形系数在坡地、水旱农田和菜地中依次减小,但一阶动力学常数依次增大。研究结果为探索TCP在紫色土壤中的迁移机制和预测防止TCP对环境的污染提供了参考依据。  相似文献   

不同施肥措施对白土腐殖质组成的影响   总被引：3，自引：0，他引：3  

吴萍萍  王家嘉  李录久 《土壤》2016,48(1):76-81

以白土稻区4年大田定位试验为基础,设置2种翻耕深度(10 cm、20 cm,分别标记为T10、T20)和4种施肥措施(单施化肥、化肥+畜禽粪肥、化肥+秸秆还田、化肥+绿肥,分别标记为F、F+M、F+S、F+G),通过腐殖质组成修改法分别提取表层土壤水溶性物质、胡敏酸、富里酸和胡敏素,研究不同施肥措施对白土腐殖质各组分碳含量的影响。结果表明:单施化肥措施下,翻耕20 cm处理(T20+F)土壤总有机碳和腐殖质各组分碳含量均低于翻耕10 cm处理(T10+F),但差异未达显著水平。在翻耕20 cm的基础上增施有机肥能显著提高土壤总有机碳和腐殖质各组分碳含量,增施畜禽粪(T20+F+M)、秸秆还田(T20+F+S)和增施绿肥(T20+F+G)3处理的土壤总有机碳、胡敏酸、富里酸和水溶性物质碳含量较T20+F处理分别提高14.57%~30.64%、10.36%~30.57%、0.74%~12.31%和14.25%~26.80%。增施有机肥显著提高胡敏素碳含量,T20+F+M、T20+F+S和T20+F+G处理较T20+F处理提高18.87%~35.78%。4年不同翻耕与施肥措施对白土腐殖质性质未产生显著影响。增施有机肥能一定程度上提高土壤PQ值、胡富比、E4/E6值和色调系数。相关性分析表明,胡敏素、胡敏酸、富里酸碳含量与总有机碳含量间均存在显著或极显著正相关,与水溶性物质碳含量间无明显相关性。  相似文献