渭北旱地叶面施钙对红富士苹果产量和品质的影响

通过喷施5种不同含钙肥料研究了叶面喷钙对旱地红富士苹果产量和品质的影响.结果表明,喷施钙肥能有效的提高产量和品质,但对果实的毒素含量无影响.单喷硝酸钙比对照增产22.42,氯化钙增产12.07,2种钙肥加萘乙酸后优于单喷,增产61.78～70.91.果实内钙含量以喷施硝酸钙最高,比对照高13.55 mg/kg,Cl-1、NO3-1含量和总酸度以对照为最高,糖酸比以单喷硝酸钙最大,达101.1.     

微生物有机肥对烤烟育苗、产量和品质的影响

针对甘肃陇东烤烟生产中存在的品质较差以及病毒病严重等问题, 于2008年通过田间试验研究微生物有机肥对烤烟育苗、产量和品质的影响。试验结果表明: (1)苗床期施用微生物有机肥有助于培育壮苗, 成苗速度快, 叶片数提前达到移栽标准, 最大叶干重和地上部干重分别比对照增加41.9%和90.1%; 总根长、比根长和根尖数分别比对照增加151.5%、25.8%和286.0%, 根系干重增加1倍; 苗床土中可培养微生物活菌数增加, 放线菌数比对照多194.7%。(2)大田移栽时再次穴施微生物有机肥极大地提高了烤烟的产量和经济效益, 改善了烟叶的品质。微生物有机肥处理的产量和产值分别比对照增加23.2%和46.5%, 中上等烟比例增加16%, 纯收入增加12 363 元·hm^-2; 烟叶的钾、总氮、烟碱、蛋白质和糖含量以及施木克值等主要品质指标接近优质烤烟的适宜值, 中下部叶的钾含量达到3%以上。     

稻草覆盖对坡地红壤培肥及作物增产的效果

研究了坡地红壤连续5年采用稻草覆盖措施对土壤肥力和作物产量的影响。结果表明,“稻草+化肥氮磷”(“Straw+NP”)处理的土壤有机碳和全氮、磷分别比不施肥(CK)的提高42.9%和17.4%、44.2%,有机碳和全氮的增幅约是纯化肥(NPK)处理的2倍。与CK和NPK处理的相比,“Straw+NP”处理能明显提高微生物生物量碳、氮、磷和溶解性有机碳、氮以及Olsen-P含量,差异达到显著(P<0.05)或极显著(P<0.01)水平。在等养分施用量的条件下,“Straw+NP”处理能显著提高油菜和甘薯的产量。因此,稻草易地覆盖是一种有效培肥坡地红壤和增加作物产量的途径。     

氮磷钾配施对多花黄精产量品质及养分吸收的影响

【目的】研究氮、磷、钾肥配施对多花黄精产量、有效成分含量和养分吸收的影响,揭示多花黄精的需肥规律,为多花黄精栽培提供理论依据。【方法】2018-2019年,采用“3414”试验方案,设置氮、磷、钾3个因子,每个因子4个水平,共计14个处理,测定不同处理多花黄精的产量、根茎多糖和皂苷含量以及地上部、地下部的N、P、K含量;采用回归分析法拟合氮、磷、钾肥施用量与多花黄精产量、根茎多糖间的肥料效应模型,使用频率分析法确定多花黄精的最佳推荐施肥量。【结果】氮、磷、钾肥配施能明显提高多花黄精的产量、根茎多糖和皂苷含量,在一定施肥区间内,多花黄精产量、根茎多糖和皂苷含量均随施肥量的增大呈先上升后下降的趋势,均在N₂P₂K₂处理（N、P₂O₅和K₂O施用量分别为160,160,80 kg/hm²）时达到最大值。氮、磷、钾肥对多花黄精产量、根茎多糖含量的影响表现为氮肥>磷肥>钾肥,氮、磷、钾肥对多花黄精根茎皂苷含量的影响表现为氮肥>钾肥>磷肥。氮、磷、钾肥配施对多花黄精地上部和地下部的N、P、K含量有明显影响,不论是地上部还是地下部,同一处理中植株N、K含量均高于P含量。拟合的氮、磷、钾肥施用量与多花黄精产量、根茎多糖间的肥料效应模型的相关性均达到显著水平（P<0.05）,可知模型拟合成功。使用频率分析法,确定了本研究土壤肥力条件下多花黄精产量达14 000 kg/hm²以上及根茎多糖含量达100 mg/g以上时的氮、磷、钾肥施用量。【结论】综合考虑产量和品质,2年生多花黄精的高产优质施肥方案为N 145~167 kg/hm²,P₂O₅ 129~158 kg/hm²,K₂O 59~80 kg/hm²,m(N)∶m(P₂O₅)∶m(K₂O)为1∶0.92∶0.45。     

慢生根瘤菌及其与花生共生机制研究进展

氮是植物生长发育所必需的大量元素之一,豆科植物通过与根瘤菌的共生固氮获得氮素.这种共生关系的建立包括结瘤和固氮两个过程,涉及复杂的互作调控机理,并受环境因素的显著影响.花生与慢生根瘤菌的共生对花生生产尤为重要,具有较多特异和未知的共生机制.本文综述了慢生根瘤菌及其与花生共生的相关内容,具体包括:(1)花生的慢生根瘤菌多...     

Residual Effect of Long Term Application of Organic and Mineral Fertilizers on Selected Chemical Properties of a Savanna Alfisol

The residual effect of organic and mineral fertilizers on selected chemical properties of an Alfisol in the long term soil fertility trial established in 1950 at Samaru, Nigerian savanna was assessed. The trial was left fallow for fourteen years due to lack of funds. Topsoil was collected from plots that received three levels of cow dung （D）, nitrogen （N） and phosphorus （P） in all possible combinations. The soils were analyzed for selected chemical properties. Except for significant effect of applied P on available P, sole application of cow dung, N or P had no significant effect on all the measured soil properties. The interaction of D and P significantly affected the mean values of exchangeable Ca, Mg, K and ECEC in the range of 1.12-1.96, 0.62-1.11, 0.37-0.64 and 2.82-4.11 cmol/kg respectively. The most important results were the ability of the plot that received neither D nor P to significantly increase these parameters than the plots that received only one of the treatments. The results show that the fallow period has changed the effects of application of organic and mineral fertilizers on the soil chemical properties under continuous cultivation by modifying them towards those of a native savanna Alfisol.     

对小型茶树开沟和施肥一体机的有限元分析

目前,在广西等地区的茶树开沟和施肥主要依靠纯人工的方法进行,虽然目前有用于茶树的开沟与施肥的机械,但限于成本以及广西丘陵地带等地理条件的制约,市场上茶树的开沟机械无法适于广西地区的使用,而人工的方法劳动强度大,不利于大规模地进行茶树的种植。为了解决农民在对小型茶树开沟和施肥过程中劳动强度大等问题,提出了一种小型茶树开沟和施肥一体机的机械,并在此之前申请了国家发明专利。运用UG对该机械进行有限元分析,以此来验证茶树开沟和施肥一体机的机械化强度满足生产要求,旨在提高茶树种植业的经济效益和产品化水平,满足茶叶的增长需求。     

卷烟焦油危害研究进展

介绍了焦油对生物活体产生的危害,从农业降焦和工业降焦方面对如何减少卷烟焦油含量达到降害目的进行了详细论述。     

硝化抑制剂和秸秆对潮棕壤碳氮转化和微生物群落特征的短期影响

氮是植物和微生物生长繁殖的必需营养元素,而氮矿化表征了土壤供氮能力。通过盆栽实验,采用同位素稀释法和磷脂脂肪酸(PLFA)法,研究了添加硝化抑制剂和秸秆条件下,潮棕壤碳氮矿化和微生物群落组成变化特征。结果表明,与施氮量N 0.1 g·kg~(-1)的单施氮肥处理(NF)相比,氮肥配施1%硝化抑制剂(NFI)的土壤铵态氮提高32%,而硝态氮降低53%。氮肥与施用量为5 g·kg~(-1)的秸秆配施(NS),土壤氮素总矿化速率增加36%,微生物生物量碳提高51%,β-葡萄糖苷酶活性提高36%,同时显著增加了土壤总PLFA以及细菌、真菌、真菌/细菌和革兰式阴性菌(P0.05),土壤呼吸熵降低50%。与氮肥配施秸秆处理(NS)相比,氮肥、秸秆和硝化抑制剂配施处理(NSI),土壤铵态氮提高33%,硝态氮下降47%。综上所述,氮肥和秸秆配施可以提高土壤微生物生物量,改变土壤微生物群落组成,配施1%(N)硝化抑制剂后降低土壤硝化速率,增加土壤供氮能力。     

Cloning and characterization of a NADP+-malic enzyme gene from Bradyrhizobium japonicum USDA110

Malic enzymes have been considered to play a key role in energy metabolism for nitrogenase reaction in bacteroids. To elucidate the physiological role of the malic enzymes in Bradyrhizobium japonicum bacteroids, a putative malic enzyme gene Bjtme1 was cloned by polymerase chain reaction (PCR) using degenerated primers from conserved regions of the protein sequences of bacterial malic enzymes and draft sequence data of the Bradyrhizobium japonicum USDA110 genome sequence project. To confirm the characteristics of the Bjtme1 gene, the protein encoded by this gene was over-expressed using a pET32a(+) system and it exhibited a NADP⁺-malic enzyme (EC 1.1.1.40) activity, indicating that Bjtme1 was the gene of the NADP⁺-malic enzyme. This is the first report on the cloning and characterization of the NADP⁺-malic enzyme gene from B. japonicum, and the gene structure was compared with that of NADP⁺-malic enzyme genes of other rhizobia.