[目的]研究蔗田滴灌施肥对土壤活性有机碳含量和甲烷排放通量的影响,探讨蔗田滴灌施肥土壤甲烷排放通量与土壤活性有机碳含量之间的关系.[方法]2018年3—12月在南宁市灌溉试验站开展不同滴灌灌水、施肥的田间试验,试验设4种施肥水平:常规施肥(F100,N 250 kg·hm-2、P2O5150 kg·hm-2、K2O 200 kg·hm-2)、增量施肥1(F110,在F100基础上增加10％)、增量施肥2(F120,在F100基础上增加20％)和减量施肥(F90,在F100基础上减少10％),以及2种滴灌灌水水平:W180(180 m3·hm-2)和W300(300 m3·hm-2).用常规法测定不同生育时期蔗田土壤甲烷排放通量和土壤活性有机碳含量,用Pearson法分析土壤甲烷排放通量与土壤活性有机碳含量的关系.[结果]在分蘖期,W300F120处理土壤可溶性有机碳(DOC)含量较W300F100提高了156％,而土壤CH4排放通量较其他处理低.在成熟期,W300F120处理土壤DOC含量较W300F110增加了114％,微生物量碳(MBC)较W300F110增加了49.6％.蔗田土壤CH4排放通量仅与土壤DOC含量呈显著正相关,相关系数为0.38.[结论]土壤DOC含量显著影响蔗田土壤甲烷排放通量.W300F120处理可以提高分蘖期和成熟期蔗田土壤可溶性有机碳含量、减少分蘖期蔗田土壤CH4排放.

对不同滴灌施肥处理下甘蔗不同生育期蔗田土壤氧化亚氮(N2O)排放通量和反硝化酶活性间关系进行了探讨.田间试验设2种滴灌灌水量水平和4种施肥量水平.2种灌水量水平分别为W0.6:180 m3 hm-2和W1D:300 m3 hm-2.4种施肥量水平F11.0:N 250 kg hm-2,P2O5 150 kg hm-2,K2O 200 kg hm-2;FQg:施肥量是F1.0的90％;Fu:施肥量是F1.0的110％;F12:施肥量是F1.D的120％.测定不同处理甘蔗4个生育期蔗田土壤N2O排放通量以及土壤硝酸还原酶(NR)、亚硝酸还原酶(NiR)和羟胺还原酶(HyR)活性.结果 表明:W0.61.2和W1.0F1.2处理甘蔗产量较高,分别为117.7thm-2和124.0thm-2.在分蘖期,所有处理土壤NR、NiR和HyR活性均达到最大值,其中W0.6F1.2和W1.DF1.2处理反硝化酶活性较高.采集土样当天蔗田土壤N2O排放通量与土壤NiR活性之间呈极显著正相关,相关系数为0.472(r0.01=0.449,n=32),说明蔗田土壤NiR活性显著影响N2O的排放通量.因此,W0.6F1.2处理,即滴灌灌水量为180 m3 hm-2及施肥量为N 300 kg hm-2、P2O5 180 kg hm-2和K2O 240 kg hm-2,在提高产量的同时对蔗田N2O的减排也有积极意义.

以“桂冠早”龙眼为试材,随机选择12株长势相近植株施用氯酸钾,设置叶面喷施、土施、叶面喷施+土施和对照(清水)等4个处理,观测不同处理开花结果状况,并测定叶片叶绿素和碳水化合物含量以及果实品质,明确氯酸钾对龙眼成花和花期调控的影响.结果 表明,施用氯酸钾可以在一定程度上促进龙眼成花,降低落果率并提高产量,但果实品质会受到一定影响.12月初施用氯酸钾对龙眼正季开花有一定的推迟作用,但推迟效果并不显著.其中,催花效果最好的是叶面喷施+土施处理,土施次之,叶面喷施作用不明显.

Myrtenal (Ⅱ) was prepared by selective oxidation of allyl methyl using α-pinene (Ⅰ) as starting material.Then,myrtenal thiosemicarbazone (Ⅲ) was prepared by condensation reaction,followed by oxidative cyclization to afford myrtenal-based thiadiazole (Ⅳ).Finally,eleven novel myrtenal-based thiadiazole-amide compounds Ⅴa~k were synthesized in 66%~81% yields by N-acylation reaction of myrtenal-based thiadiazole with a series of acyl chlorides.All the target compounds were characterized by FTIR,1HNMR,13CNMR,and ESI-MS.The antifungal and herbicidal activities were also evaluated in this study.The results showed that compounds Ⅴa~k displayed different antifungal activities against Physalospora piricola,Fusarium oxysporum f.sp.Cucumerinum,Cercospora arachidicola,Fusarium graminearum and Alternaria solani at 50 mg/L.Myrtenal-based thiadiazole-acetamide (Ⅴa),myrtenal-based thiadiazole-chloroacetamide (Ⅴb),and myrtenal-based thiadiazole-n-propionamide (Ⅴc) had inhibition rates of 93.0%,93.0% and 98.2% against Physalospora piricola,respectively.Compound Ⅴb had inhibition rate of 84.3% against F.oxysporum f.sp.Cucumerinum,exhibiting comparable or even better antifungal activity than the commercial fungicide azoxystrobin (positive control,the inhibition rates of 96.0% and 87.5% against P.piricola and F.oxysporum f.sp.Cucumerinum,respectively).The structure-activity relationship of synthesized compounds indicated that the aliphatic amide derivatives exhibited better antifungal activity than the others.In addition,at 100 mg/L,myrtenal-based thiadiazole-n-propionamide (Ⅴc) showed better growth inhibition activity against root of rape (Brassica campestris) with the inhibition rate of 79.6%than the commercial herbicide flumioxazin with the inhibition rate of 63.0%.

α-Campholenic aldehyde was prepared by the epoxidation and catalytic isomerization ofα-pinene. Then,α-campholenic aldehyde-based thiadiazole was prepared by the cyclization reaction of α-campholenic aldehyde-based thiosemicarbazone, which was obtained by the reaction of thiosemicarbazide withα-campholenic aldehyde. Finally,twelve novel 2-sustituted acylamino-5-(α-campholenic aldehyde )-based-1, 3, 4-thiadiazole compounds ( 6a- 6l ) were synthesized by the N-acylation reactions ofα-campholenic aldehyde-based thiadiazole with a series of acyl chlorides. The target compounds were characterized by FT-IR, 1H NMR,13C NMR, and ESI-MS. Antifungal activity test showed that, at the concentration of 50 mg/L, the target compounds exhibited different antifungal activities against the five tested fungi. Some of them exhibited antifungal activities were close to or even better than the commercial azoxystrobin used as positive control in this study. Among them,in which compound 6j had an inhibition rate of 94. 4% against Fusarium graminearum,and compound 6h had an inhibition rate of 97. 7% against Physalospora piricola.

以α-蒎烯为起始原料,经氧化制得桃金娘烯酸(3);脂肪族二酸在POC13作用下与氨基硫脲经脱水环合制得脂肪族双噻二唑(4a～4h);4a～4h分别与3经脱水反应合成了8个新型的桃金娘烯醛基双酰胺噻二唑化合物(5a～5h),其结构经1H NMR,13C NMR,IR和ESI-MS表征.抗真菌活性测试结果表明,在用药量为50μg·mL-1时,5a～5h对黄瓜枯萎病菌、花生褐斑病菌、苹果轮纹病菌、番茄早疫病菌和小麦赤霉病菌均有一定的抑制作用,其中桃金娘烯醛-辛二酸基双酰胺-噻二唑(5f)对苹果轮纹病菌的抑制率为60.3％,桃金娘烯醛-丁二酸基双酰胺-噻二唑(5b)和桃金娘烯醛-癸二酸基双酰胺-噻二唑(5h)对小麦赤霉病菌的抑制率分别为52.8％和54.4％.