土壤封闭型除草剂对油菜田土壤细菌多样性的影响

土壤封闭除草是一种有效的油菜田化学除草措施。为评估不同土壤封闭型除草剂对油菜田土壤微生物的影响,使用16S rRNA扩增子测序技术分析了四种常用土壤封闭型除草剂甲草胺、异丙甲草胺、乙草胺及精异丙甲草胺处理后土壤微生物结构及多样性的变化情况。结果表明,土壤封闭型除草剂处理会导致油菜田土壤细菌多样性显著下降,其中甲草胺处理影响最大;但在除草剂处理一段时间后土壤中细菌群落多样性与丰富度逐渐恢复。土壤封闭型除草剂处理对油菜土壤中放线菌门、酸杆菌门等影响较大,甲草胺较其他土壤封闭型除草剂处理中土壤细菌在门水平上变化最大。土壤封闭型除草剂处理60 d后能增加与污染物降解、反硝化、光合作用、抑制病原菌生长、根际促生相关功能细菌的丰度;减少与吸收营养、排泄代谢物相关的功能细菌的丰度。综合研究结果,土壤封闭型除草剂对油菜田土壤微生物多样性和群落结构有一定影响,但随着处理时间推移,除草剂对土壤微生物多样性影响程度逐渐降低。     

除草剂及尿素混剂对稻田氨化细菌的影响

 就除草剂及尿素混剂在稻田施用后的效果进行了研究。除草剂丁草胺、除草醚、农得时和果尔与尿素混用，与单施尿素处理相比，可以获得较好的杂草防除效果并提高水稻产量。丁草胺、禾大壮、杀草丹、除草醚以及丁草胺+二甲四氯在一定使用剂量下均显著地抑制脲芽孢八叠球菌［Sporosarcina ureae (Beijernck) Kluyver et van Niel］的繁殖。而快杀稗、都尔、二甲四氯、苯达松、果尔、农得时、草克星和乙草胺对脲芽孢八叠球菌无影响。     

控释肥对大豆根际土壤微生物数目、肥力及大豆农艺性状的影响

采用无肥、常规肥、控释尿素和控释复合肥4种肥料处理,于大豆播种前和成熟期对大豆根际土壤的细菌、真菌、放线菌采用平板计数法进行测定;并对大豆成熟期根际土壤微生物数量变化、土壤养分含量变化及大豆农艺性状及产量相关因素进行分析.结果表明:与无肥和常规肥比较,控释尿素和控释复合肥可明显增加土壤中细菌、真菌及放线菌数目,并且控释...     

不同施肥处理对大豆生育期内土壤微生物的影响

研究长期不同施肥处理措施条件下,大豆在不同生育期中土壤细菌数量的动态变化与土壤微生物总数的动态变化之间的关系及其变化趋势.结果表明,土壤细菌数量的动态变化决定土壤微生物总数的动态变化,各处理土壤中细菌总数由花期逐渐增加,结荚期达最大值,到成熟期明显下降.各个时期土壤微生物量碳的变化与土壤细菌数量的变化趋势一致,有机 无机肥可明显提高土壤微生物数量和微生物碳量.     

10种除草剂对武育粳3号生长及“小粒穗”形成的影响

 采用盆栽试验研究了10种除草剂对水稻生长及对“小粒穗”形成的影响。 在土壤处理中,用药处理后10、20 d,乙草胺225、337.5 g/hm2处理和乙草胺225 g/hm2+苄嘧磺隆22.5 g/hm2混用处理显著地 (P=0.05)抑制水稻株高,但并不影响分蘖发生,到用药后40 d,土壤处理药剂处理的水稻株高与对照无显著差异;在处理后10、20 d, 氯磺隆0.375、0.75、1.5 g/hm2处理可显著(P=0.05)影响水稻株高,而甲磺隆0.75、1.5 g/hm2处理在用药后30、40 d仍显著影响水稻株高,氯磺隆1.5 g/hm2和甲磺隆0.75、1.5 g/hm2在药后10、20 d也显著地影响水稻茎蘖数,但在药后40 d两药剂处理与对照均无显著差异。茎叶处理中,药剂处理对水稻株高、分蘖产生无显著的抑制作用。同时, 除草剂处理基本上不对水稻结实性产生影响,并未发现典型的“小粒穗”,表明稻田使用除草剂不是引起水稻“小粒穗”的直接原因。     

复配化学除草剂蔗田应用效果初报

1994年在广西农业大学试验农场进行试验,每亩用除草剂农大复配1号(A)150ml、农大复配2号(B)50ml,40％阿特拉津(C)250ml兑水50kg在甘蔗下种后20天进行土壤喷药处理,以喷清水为对照。试验结果表明,喷施农大复配1号、2号和阿特拉津,喷药后50天内均能明显地杀灭蔗田一年生单、双子叶杂草,农大夏配1、2号对多年生宿根性杂草也有较明显的抑制作用。三种除草剂的防效分别为87.6％(A)、88.6％(B)和81.9％(C),除草效果显著。农大复配2号除草效果优于复配1号,农大复配1号又优于阿特拉津。使用除草剂对甘蔗萌芽出苗无抑制作用。     

茶树根际土壤物质的自毒潜力及其对土壤微生物多样性的影响

为了分析茶树根际土壤物质对茶树根际土壤微生物多样性的影响,本研究以植茶年限0、3、9、25 a的铁观音茶树根际土壤为材料,采用不同极性树脂吸附茶树根际土壤物质并洗脱,探讨不同植茶年限茶树根际土壤物质的自毒潜力及其对土壤微生物多样性的影响。结果表明,不同极性树脂吸附洗脱液以ADS-7树脂洗脱液对受体根长的抑制作用最强。ADS-7树脂吸附洗脱液处理重新种植的茶树后,随着土壤植茶年限的增加,茶树根际土壤细菌数量呈现下降趋势。相关性分析结果表明,与土壤年限呈正相关的细菌T-RFs片段15个,涉及8个纲,31种细菌,按照其功能可分为4类,其中病原菌19种,占比61.29%;负相关细菌T-RFs片段18个,涉及11个纲,31种细菌,按照其功能可分为6类,其中与抑制病原菌、碳素循环、氮素循环、硫素循环、土壤质地改善相关的细菌总占比达到83.87%。综上表明,ADS-7树脂洗脱液处理重新种植的茶树后,随着土壤植茶年限的增加,茶树根际土壤病原菌数量大幅上升,益生菌与土壤养分循环相关的细菌数量显著下降,土壤微生物生态系统平衡失调。     

小麦秸秆覆盖量对不同植烟土壤微生物数量的影响

采用田间小区试验,研究了小麦秸秆覆盖量(覆盖量为0、250、500、750 kg/(667 m2)等4个处理)对不同植烟土壤微生物数量的影响。结果表明:覆盖量越大,地烟和田烟根际土壤细菌、放线菌和纤维分解菌的数量越大,覆盖量为750 kg/(667 m2)时,采收后,地烟和田烟土壤中细菌、放线菌和纤维分解菌的数量最多,分别比对照增加了112.92%、88.97%、311.87%和176.13%、43.40%、233.85%。地烟不同秸秆覆盖量处理的土壤细菌数量较无秸秆覆盖处理增加了1.81～2.13倍;放线菌增加了1.08～1.89倍;纤维分解菌增加了1.49～4.1倍;固氮菌则在覆盖量为500 kg/(667 m2)时增加的数量最多,显著高于无秸秆覆盖;秸秆覆盖量对真菌的数量也有影响。田烟不同秸秆覆盖量处理的土壤根际细菌数量较无秸秆覆盖处理增加了1.87～2.76倍;放线菌增加了1.12～1.43倍;纤维分解菌增加了1.3～3.39倍;覆盖量为500 kg/(667 m2)时,土壤中真菌和固氮菌的数量最多,分别比无秸秆覆盖增加2.24倍、1.60倍,且差异显著。     

不同施肥处理对大豆根际土壤微生物及土壤肥力影响

为研究不同施肥方式对大豆根际土壤微生物数量及土壤肥力影响,采用无肥、常规肥、有机肥、常规施肥+生物肥4种肥料处理,分别于大豆播种前、苗期、花期、鼓粒期和成熟期对大豆根际土壤的细菌、真菌、放线菌进行测定.结果表明:肥料的施用可提高土壤微生物的数目及土壤肥力,其中有机肥处理与常规肥+生物肥处理在大豆各生育时期可明显增加土壤...     

棉田脲酶抑制剂最佳用量试验

长效尿素是用脲酶抑制剂和尿素按一定比例混合而成的长效肥料。其原理是应用脲酶抑制剂抑制土壤中脲酶的活性,减缓其对尿素的分解速度,延长尿素肥效期,提高肥效,以达到土壤供肥和棉花需肥相协调,增加棉花产量的目的。由于不同肥力类型土壤中脲酶含量和活性不同,脲酶抑制剂的最佳用量也应不同。为此从1990年开始,用3年时间在德州市、临邑、宁津等地进行了棉花应用长效尿素脲酶抑制剂最佳用量试验。     

稻蟹共作模式生态效应研究进展

主要从土壤、水环境和杂草防控三个方面,对目前我国稻蟹共作模式下田间生态的研究现状进行了总结与分析.提出了几种目前比较常见的稻蟹共作模式,即有机稻蟹和常规稻蟹两种普遍模式.分析了稻蟹共作对土壤理化性质、土壤酶活性和根际微生物区系的影响.养蟹稻田可以显著降低土壤容重,而总孔隙度及全氮、全磷、碱解氮、有效磷、速效钾和土壤有机质含量都显著增加;显著提高0~10 cm土壤脲酶、蛋白酶、脱氢酶以及过氧化氢酶的活性;土壤根际微生物以细菌为主要菌群,氨化细菌、反硝化细菌、嫌气性纤维素分解菌、好气性自生固氮菌、亚硝酸细菌数量显著高于单作水稻;与常规稻蟹相比,有机稻蟹的土壤性状表现更好.稻蟹模式下浮游动植物的多样性和生物量显著低于单作水稻,而水体中溶解氧(DO)明显偏低,硝酸盐、磷酸盐含量显著高于不养蟹稻田.稻田养蟹能够显著抑制稻田4种优势杂草的密度,对于稻田杂草的防控效果明显.     

Water deficit effects on potato leaf growth and transpiration: Utilizing fraction extractable soil water for comparison with other crops

Numerous studies have demonstrated that physiological responses of many crops to the fraction of extractable soil water conforms to a generalizable pattern. This suggests that differences among crops in their drought tolerance are largely due to differences in the total amount of transpirable water the crop can extract. Potato is frequently assumed to be more drought sensitive than other agronomic crops due, at least in part, to a shallow root system. In the research reported here, potato leaf growth and transpiration response to water deficits were determined as a function of fraction transpirable soil water (FTSW). Transpiration was unaffected by water stress until a critical FTSW was achieved when 64% to 80% of the extractable soil water was depleted depending on the cultivar. This was similar to the response reported for 8 other agronomic crops. In terms of transpiration, potato hypersensitivity to drought stress appears to be due to less effective soil water extraction. Leaf growth, however, showed a unique response to soil water deficits. Leaf growth began to decline when 40% of the extractable soil water was depleted. The associated critical FTSW was higher than any previously reported for all other crops. These data indicate that in addition to extracting less soil water, an additional physiological process related to leaf expansion must be contributing to the potato’s hypersensitivity to drought.     

施氮量对玉米根区土壤微生物区系的影响

采用稀释平板涂布法研究3个施氮量水平对不同栽培模式玉米根区土壤中可培养细菌、真菌和放线菌数量的差异性。结果表明,施氮能大大促进覆膜玉米根区土壤细菌、放线菌及覆草模式真菌数量的增加。玉米根区土壤微生物数量主要受玉米根系的影响,根外土壤微生物的数量主要受施氮量的影响。施氮能缩小常规模式玉米根区与根外土壤细菌和真菌数量的差异,增大常规模式玉米根区与根外土壤放线菌数量的差异,还能缩小覆盖模式玉米根区与根外土壤中3大类微生物数量的差异。玉米根区土壤微生物数量高于根外,但施氮量较高(240 kg/hm2)时,在覆膜和常规对照条件下土壤真菌数量及覆草模式下土壤细菌数量表现为根外高于根区。     

秸秆深还对土壤水分转移及产量的影响

采用田间试验方法,将玉米秸秆切段、粗粉碎、细粉碎、细粉碎后压粒和细粉碎后氨化处理,研究玉米秸秆深施还田对土壤水分转移及产量的影响。结果表明,秸秆粉碎程度越细,吸水能力越强,深施后土壤渗水速度越快;粉碎的秸秆较其他处理更能促进土壤水分竖直方向转移;各处理的蓄水能力表现为粉碎状秸秆处理段状秸秆处理CK(不施秸秆),且细粉碎、细粉碎后氨化处理在还田初期就能呈现出明显的蓄水效果;秸秆粉碎状态越细,深施后土壤容重减小的速度和幅度越大,细粉碎处理和细粉碎后氨化处理能在还田初期对减小土壤容重产生明显作用,播种后25 d,土壤容重减小幅度最大,分别达0.052和0.045 g/cm3;秸秆深施还田有效提高玉米产量,产量排序为细粉碎细粉碎后氨化处理粗粉碎细粉碎后压粒秸秆切段CK(不施秸秆),其中细粉碎处理对玉米产量的增加影响最明显。     

除草剂苯磺隆对麦田土壤酶活性的影响

为了评价施用苯磺隆对土壤环境的生态效应,在大田条件下,研究了苯磺隆对麦田土壤酶活性的影响。结果表明,苯磺隆对土壤过氧化氢酶活性具有激活作用,且浓度越高,激活作用越强;对土壤脲酶活性的影响表现为0.13、0.25和0.50 g·kg-1浓度处理轻微激活,1.00 g·kg-1浓度处理抑制;苯磺隆在处理初期抑制土壤多酚氧化酶活性,喷药后10 d开始激活,至30 d逐渐恢复至清水对照水平;苯磺隆对土壤蔗糖酶活性具有抑制作用。苯磺隆对各土壤酶活性的影响均为短期效应,除1.00 g·kg-1浓度处理外,其余处理酶活性在试验后期均能逐渐恢复至对照水平,对麦田土壤生态系统相对安全。     

Interactive effects of nitrogen and phosphorus on verticillium wilt of Russet Burbank potato

A three-year field study was conducted during 1984–1986 to determine the interactive effects of nitrogen and phosphorus fertilization on Verticillium wilt, and yield and quality of continuously-cropped Russet Burbank potato. The experiment was conducted on a calcareous, silt loam soil with low initial levels of NO₃-N (0.9 mg/kg), P (3.5 mg/kg), andVerticillium dahliae (9 cfu/g of soil). The experimental design consisted of a factorial combination of three N treatments (unfertilized check, preplant N or split N) and three P treatments (0,120, or 240 kg P/ha) applied to the same plots during the three-year study. Nitrogen was applied at 0 or 300 kg N/ha in 1984 and 0 or 240 kg N/ha in 1985 and 1986. By the spring of 1986, soil P concentrations for the 0,120, and 240 kg P/ha treatments had increased to 7, 25, and 50 mg/kg and no additional P was applied. In addition to suppressing Verticillium wilt by as much as 95%, N & P treatments also reduced the rate of increase of soilborne inoculum ofV. dahliae. After one season of cropping, the N treatment providing the most efficient N fertilization (300 kg N/ha, split-application) resulted in significantly (p=0.01) lowerV. dahliae counts in soil than the other N treatments. After two seasons of continuous cropping, applying 120 to 240 kg P/ha produced lower populations ofV. dahliae in soil compared to the treatment with no added P. Generally, as N and P treatments approached the highest levels, both wilt incidence andV. dahliae colonization values were reduced. There was a progressive reduction in total yield in nearly all treatments during each year of continuous cropping. Reduction of yield and increased Verticillium wilt incidence was generally greater with N or P deficient plants than with optimally fertilized plants. The highest total and U.S. No. 1 yields and least Verticillium wilt were obtained each year by applying split N and 240 kg P/ha. Results show that optimal N and P can minimize both Verticillium wilt and yield losses that normally occur with intensive potato cropping.     

Effects of Soil Temperature on Growth and Root Function in Rice

Abstract

The objective of this study was to clarify the effects of soil temperature in the stage from late tillering to panicle initiation (SI) and during the grain-filling stage (SII) on grain setting, dry matter production, photosynthesis, non-structural carbohydrate (NSC), xylem exudation and abscisic acid (ABA) levels in rice (Oryza sativa L. cv. Koshihikari). Rice plants were exposed to four different soil temperatures during SI or SII: 17.5, 25, 31.5 and 36.5°C (ST18, ST25, ST32 and ST37, respectively). The yield, yield components, grain filling and quality in SI were negatively influenced by high soil temperature of 37°C. On the other hand, there was no significant difference in those characters among temperature treatments in SII. The root/shoot ratio was smallest in the ST37 plants in both SI and SII, mainly due to their lighter root weight. At 7 days after initiation of treatment (DAT) in both SI and SII, the photosynthetic and xylem exudation rate tended to increase slightly as soil temperature increased up to 32°C. At 21 DAT, however, the photosynthetic rate was lowest in ST37, with concurrent decrease of diffusion conductance and SPAD value. In addition, decrease of NSC concentration in stem and xylem exudation rate, and increase of ABA level in leaves and xylem exudate were observed in ST37 plants at 21 DAT. These results suggested that high soil temperature before heading especially influenced yield, grain quality and plant growth. Possible mechanisms of the effect of soil temperature are discussed.     

转Bt基因水稻Cry1Ab杀虫蛋白在水稻土中的降解

室内研究了转 Bt基因水稻克螟稻 2号和华池B6 叶片中的Cry1Ab杀虫蛋白在稻田水稻土中的降解动态。分别将克螟稻 2号的粉碎叶片和华池B6 的整张叶片埋入 3种土壤 (即老黄筋泥田、青紫泥田和黄松田 )中 ,此后每隔 6～ 10d测定土壤或叶片中的Cry1Ab含量。克螟稻 2号粉碎叶片中的Cry1Ab均以处理后的前 36d,尤其是前 6d的降解较快 ,其中在青紫泥田中最快 ,黄松田中最慢。在处理后 6～ 36d内 ,不同土壤中的Cry1Ab残留量有显著差异 ,黄松田中的明显最高 ,老黄筋泥田中的次之 ,青紫泥田中的为最低 ;此后土壤间的残留量差异逐渐缩小 ,至处理后 78d差异已不明显。土壤淹水可显著加快华池B6 叶片中Cry1Ab的降解 ,且淹水后其降解动态在不同土壤之间十分相似 ;淹水对Cry1Ab降解的促进作用仅发生在前 12d之内 ,此后多数时间内残留量在淹水与非淹水处理间无显著差异。建立了各处理中Cry1Ab降解的动力学指数方程 ,相应地得出了其降解的半衰期。还讨论了土壤有机质和微生物等因子对土壤中Cry1Ab降解的影响。     

Continuous Application of Biochar Inoculated with Root Nodule Bacteria to Subsoil Enhances Yield of Soybean by the Nodulation Control using Crack Fertilization Technique

Abstract

Crack fertilization is a soybean cultivation technique for nodulation control in which midterm subsoiling is used to supply fertilizing materials to deep soil just before the flowering stage. This study examined the effects of fertilizing materials and the continuous application of nodulation control, on soybean yield enhancement in two field experiments. The survival of nodule bacteria in deep soil was also evaluated by a bioassay of nodule bacteria in a root box. When the nodule bacteria on biochar were continuously applied without any other chemical fertilizers for three successive years, seed weight was significantly heavier being up to 1.34 times that of the control. The application of nodulation control in the previous year but not in the experimental year did not have residual effects on seed weight. The enhancement of seed weight in a farm field converted from a paddy was much lower. This may be partly attributed to the midterm tillage practice, whichdestroys the crack structure after the nodulation control, together with soil water status and cultivar differences. Nodule growth and nitrogen fixation activities significantly increased in the soybean plants grown on the soil collected from the subsoil to which nodule bacteria on biochar had been applied the previous year. This suggests that nodule bacteria in the subsoil survived in the biochar habitat for at least a year after application. These results indicate that nodulation control by the crack fertilization technique leads to yield enhancement when nodule bacteria on biochar are continuously applied.     

Development of amino acid-modified PET/PA6 segmented pie bicomponent spunbonded microfiber nonwoven for bilirubin affinity adsorption

A novel affinity membrane based on PET/PA6 segmented pie bicomponent spunbonded microfiber nonwoven (PET/PA6 SBSNW) was developed for bilirubin adsorption. PET/PA6 SBSNW was initially fabricated as microfiber nonwoven fabric, and was then ammoniated with ethylenediamine (ETDA). Finally, amino acids as affinity ligands were immobilized on the ammoniated PET/PA6 SBSNW. The amino acid-modified PET/PA6 SBSNW was applied to adsorb bilirubin, and the effects of pH, temperature, species of affinity ligands, and time were investigated. The results showed that amino acid-modified PET/PA6 SBSNW has decent adsorption performance, and adsorption capacity of PET/PA6 SBSNW-Lys peaked at 388.35 mg/g.