甲基溴替代技术对番茄温室土壤养分及微生物量碳的影响

试验于2001~2003年研究了甲基溴替代技术对温室番茄土壤养分及微生物量碳的影响,替代技术为太阳能配合生防制剂木霉菌(SS BCA)、甲基溴及减量甲基溴(常规用量75%)覆盖不透膜(MB VIF)、威百亩(MS)及减量威百亩(常规用量75%)覆盖不透膜(MS VIF)。结果表明:2001~2002年各处理对土壤pH、有效磷、有效钾及阳离子交换量影响不显著,甲基溴熏蒸(VIF膜和PE膜)提高了土壤铵态氮的释放;4个化学处理(MB,MB VIF,MS及MS VIF)可显著降低土壤微生物量碳含量,但彼此之间差异不显著。2002~2003年增施有机肥后,4个化学处理效果与2001~2002年相同,太阳能消毒则提高了土壤铵态氮的释放,对土壤微生物碳的影响也达到化学处理的水平。两季番茄中土壤微生物量碳均季节性波动明显,施用有机肥可加速微生物的周转。     

高温逆境下嫁接番茄耐热特性研究

以赤茄、粘毛茄、北农茄砧和托鲁巴姆为砧木,研究了嫁接番茄对夏季高温的抵御能力,以及对果实品质的影响。结果表明：高温下北农茄砧嫁接番茄叶片游离脯氨酸、蛋白质的含量均较番茄自根苗多,同时POD与APX活性较高,表现出较强的抗热能力;以赤茄为砧木嫁接番茄叶片POD与APX活性较低,叶片游离脯氨酸、蛋白质的含量减少,耐热性降低。嫁接显著地提高了番茄果实有机酸含量,降低了果实蛋白质含量。嫁接对果实维生素C、还原糖含量影响较小。     

高温逆境下嫁接番茄耐热特性研究

以赤茄、粘毛茄、北农茄砧和托鲁巴姆为砧木,研究了嫁接番茄对夏季高温的抵御能力,以及对果实品质的影响。结果表明:高温下北农茄砧嫁接番茄叶片游离脯氨酸、蛋白质的含量均较番茄自根苗多,同时POD与APX活性较高,表现出较强的抗热能力;以赤茄为砧木嫁接番茄叶片POD与APX活性较低,叶片游离脯氨酸、蛋白质的含量减少,耐热性降低。嫁接显著地提高了番茄果实有机酸含量,降低了果实蛋白质含量。嫁接对果实维生素C、还原糖含量影响较小。     

上海地区番茄黄化曲叶病毒病的鉴定及嫁接接种法研究

番茄黄化曲叶病毒（tomato yellow leaf curl virus,TYLCV）是一种由烟粉虱（Bemisia tabaei）和嫁接传播的双生病毒,在热带、亚热带地区给番茄生产造成严重威胁。根据番茄黄化曲叶病毒的保守序列设计一对引物,运用PCR技术从上海地区的感病番茄中扩增出一条575bp的特异带,而健康植株无此带。测序表明该序列与番茄黄化曲叶病毒具有极高的同源性（97％～99％）。将健康接穗嫁接到感染番茄黄化曲叶病毒的番茄砧木上,间隔15d和30d,分别提取接穗的DNA,并用PCR法检测病毒,发现嫁接15d后在部分接穗中检测到TYLCV病毒,嫁接30d后在所有的接穗中均检测到病毒,因此,嫁接法可以作为番茄黄化曲叶病毒病的接种鉴定方法。     

樱桃番茄嫁接种苗生长及养分吸收差异研究

以海茄砧1号为砧木,以红粉A4为接穗,研究不同苗龄砧木与接穗养分吸收差异及接穗叶片数量对樱桃番茄嫁接种苗生长发育的影响.结果表明:同苗龄期,种苗所需氮磷钾钙镁养分砧木皆大于接穗,随着苗龄的增加,砧木与接穗氮磷钾含量均显著下降,接穗钙、镁含量趋向于增加,与砧木表现不同;随着苗龄的增加,砧木与接穗氮磷钾钙镁积累量均显著增加...     

临夏州日光温室番茄嫁接技术探讨

甘肃省临夏州地处黄土高原与青藏高原的过渡地带,具有独特的气候和区位优势,为发展设施农业提供了良好条件。为提高临夏州日光温室番茄产量和品质、促进番茄产业健康可持续发展,重点从砧木与接穗的选择、嫁接前准备工作、嫁接操作及嫁接后期管理等方面分析日光温室番茄嫁接技术。     

日光温室番茄根结线虫无公害综合防治技术

日光温室番茄是淄博市保护地栽培的主要蔬菜种类之一,但近年来根结线虫危害日趋严重,使番茄产量锐减、品质下降,该文总结了利用抗病品种,石灰氮-太阳能消毒,线虫疫苗嫁接和生物物质利用等综合技术防治根结线虫的具体方法和效果。     

日光温室番茄根结线虫无公害综合防治技术

日光温室番茄是淄博市保护地栽培的主要蔬菜种类之一,但近年来根结线虫危害日趋严重,使番茄产量锐减、品质下降,该文总结了利用抗病品种,石灰氮-太阳能消毒,线虫疫苗嫁接和生物物质利用等综合技术防治根结线虫的具体方法和效果.     

用捕食性单齿线虫防治番茄根结线虫

用捕食性单齿线虫可以明显抑制由南方根结线虫引起的番茄根结症状。如果向土壤添加印度楝和蓖麻叶,则对根结症状的发展有更好的控制效果。     

嫁接对番茄连作土壤环境及土壤酶活性消减的影响

连作障碍是我国番茄集约化生产的瓶颈,为了探索适宜连作的栽培模式,试验以易感青枯病番茄品种‘梅赛德斯’实生苗及以抗病品种‘爱好’为砧木,‘梅赛德斯’为接穗的嫁接苗为试材,通过分析检测连作3年下根际土壤养分和土壤酶活性指标的变化,结合土传病害发生情况,分析嫁接对番茄连作障碍下土壤环境消减的影响。结果表明：连作3年内,嫁接苗青枯病的发病率都极显著低于实生苗,说明嫁接苗较实生苗极显著降低了土传病害发生率;嫁接有利于缓解番茄根际土壤中碱解氮含量的升高及连作导致的土壤酸化问题;同时,嫁接有利于缓解番茄根际土壤多酚氧化酶活性、尿酶活性和蔗糖酶活性的下降;另外,连作对嫁接苗种植土壤有机质含量的影响相对不显著,而实生苗在连作1年后显著降低了土壤有机质含量;嫁接对番茄速效钾、有效磷含量的影响无明显规律性。综上所述,嫁接对改善番茄根际土壤化学性质和土壤酶活性有积极作用。     

4种熏蒸剂处理对土壤可溶性有机氮和微生物量碳氮的影响

采用室内恒温通气培养法,以北京大棚蔬菜地土壤为研究对象,以未使用熏蒸剂土壤为对照,研究4种熏蒸剂[氯化苦(Pic)、1,3-二氯丙烯(1,3-D)、二甲基二硫(DMDS)和威百亩(MS)]对土壤可溶性氮素和微生物量碳、氮的影响。结果表明,4种熏蒸剂处理均能增加土壤中可溶性有机氮的含量,熏蒸处理后敞气0 d时,Pic、MS、DMDS和1,3-D处理的土壤可溶性有机氮累积量分别为47.55 mg·kg-1、42.15 mg·kg-1、40.34 mg·kg-1和32.02 mg·kg-1,较对照(29.97 mg·kg-1)分别增加58.67%、40.65%、34.61%和6.87%。敞气后14~84 d,Pic、DMDS和MS处理DON含量仍持续上升,1,3-D和对照变化不大,各处理之间DON含量差异显著。4种熏蒸剂处理后短时间内,土壤中可溶性氨基酸(DAA)与对照相比大幅上升,在熏蒸后7 d达到最大值,其中Pic处理的上升幅度最大,为12.87 mg·kg-1,对照DAA含量最低,为5.74 mg·kg-1。4种熏蒸剂处理之后,土壤中微生物量碳和氮均呈现急剧下降的趋势,其中Pic处理对微生物的杀灭作用最强,敞气后0 d,Pic处理的微生物量碳和微生物量氮含量分别比对照下降69.39%和70.95%,MS和DMDS次之,1,3-D的杀灭作用最弱。     

Enzyme activities in agricultural soils fumigated with methyl bromide alternatives

Pre-plant fumigation of agricultural soils with a combination of methyl bromide (MeBr) and chloropicrin (CP) to control nematodes, soil-borne pathogens and weeds has been a common practice in strawberry (Fragaria X ananassa Duchesne) production since the 1960s. MeBr will be phased out by 2005, but little is known about the impacts of alternative fumigants on soil microbial processes. We investigated the response of microbial biomass and enzyme activities in soils fumigated over two years with MeBr+CP and the alternatives propargyl bromide (PrBr), InLine, Midas and CP. Results were compared to control soils, which were not fumigated for the last 4-5 years for Watsonville and Oxnard, respectively, but had a 10 year history of MeBr+CP fumigation (history soils). Soil samples (0-15 cm) were taken from two sites in the coastal areas of California, USA, in Watsonville and Oxnard, at peak strawberry production after two years of repeated application. In addition to the soil enzymes, the activities of purified reference enzymes of β-glucosidase, acid phosphatase and arylsulfatase were assayed before and after fumigation with MeBr+CP and alternative biocides. At the Oxnard site, microbial respiration significantly decreased in soils fumigated with MeBr+CP (P=0.036), while microbial biomass C and N showed no response to fumigation at both sites. These results may indicate that fumigation promotes the growth of resistant species or that soil microorganisms had recovered at the time of sampling. Repeated soil fumigation with MeBr+CP significantly decreased the activities of β-glucosidase and acid phosphatase at the Watsonville site, and dehydrogenase activity at the Oxnard site. Although, enzyme activities in soils fumigated with PrBr, InLine, Midas and CP were lower compared to the control soil, effects were, in general, not significant. Fumigation with MeBr+CP and alternatives reduced the activities of purified reference enzymes by 13, 76 and 28% for acid phosphatase, β-glucosidase and arylsulfatase, respectively. Mean enzyme protein concentrations in fumigated agricultural soils were 2.93, 0.105, and 2.95 mg protein kg⁻¹ soil for acid phosphatase, β-glucosidase and arylsulfatase, respectively, all lower than in control soils. Organic matter turnover and nutrient cycling, and thus, the long-term productivity of agricultural soils seem unaffected in soils repeatedly fumigated with PrBr, InLine, Midas and CP.     

Microbial community composition and enzyme activities in a sandy loam soil after fumigation with methyl bromide or alternative biocides

A sandy loam soil was fumigated in microcosms for 24 h with methyl bromide and chloropicrin (MeBr+CP), propargyl bromide (PrBr), combinations of 1,3-dichloropropene and CP (InLine), iodomethane and CP (Midas), an emulsifiable concentrate of CP (CP-EC), or methyl isothiocyanate (MITC). The effects of these pesticides on fatty acid methyl ester (FAME) profiles and selected enzymatic activities were evaluated in fumigated soils and a nonfumigated control at 1, 3, 7, 14, 21, 28, and 90 days post-fumigation. Bacterial (a15:0, i15:0, i16:0, cy17:0, a17:0 and i17:0) and fungal (18:2ω6, 18:3ω6, 18:1ω9) FAMEs were initially (1 day post-fumigation) reduced by fumigation with CP-EC, InLine, and Midas. Microbial communities of soils fumigated with MeBr+CP, MITC, and PrBr resembled those of the control soil. At 14-28 days post-fumigation, FAME profiles were changed in all fumigated soils relative to the control, with the exception of soils treated with MITC. At 90 days post-fumigation, FAME profiles suggested that actinomycetes (10 Me 16:0, 10 Me 17:0, 10 Me 18:0) and Gram-positive bacteria may recover preferentially after fumigation with most of the pesticides studied. Among the fumigants tested, InLine, Midas, and CP-EC had a higher potential to alter the microbial community structure in the longer term than MeBr+CP, PrBr and MITC, with MITC having the least effect. Soil enzyme activities in fumigated microcosms were significantly (P≤0.037) different from the nonfumigated soil, with the exception of β-glucosidase in soils treated with PrBr and MITC, and dehydrogenase in MeBr+CP-fumigated soils. Over the 90-day study, soil fumigation (average of all fumigants and sampling dates) reduced the activities of arylsulfatase (62%), dehydrogenase (35%), acid phosphatase (22%), and β-glucosidase (6%), suggesting that S mineralization in soils and the total oxidative potential of microorganisms were more affected by fumigation than P and C mineralization. This study also indicates that soil fumigation with MeBr+CP alternative biocides has the potential to alter microbial communities and important key reactions involved in nutrient transformation.     

Precision nutrient gradients ‐a component for optimal production

Abstract

Crop production, equivalent or exceeding any that has been attained or predicted, is possible from the sandy soils of peninsular Florida. However, extreme variability occurs from season to season, from field to field, and even within fields. Well managed field corn in Florida has averaged 50–70 bu/A, while maximum yields with irrigation have rarely exceeded 125 bu/A. Production of fresh market tomatoes, which in Florida have an annual value of 100 million dollars, varies from failure to 25 tons/A using the common cultural procedures.

By utilizing a precision production system, consistent yields of 45 to 50 tons/A of fresh market tomatoes as well as 160–180 bu/A of field corn have been obtained. Combinations of controllable and non‐controllable factors with nutrition as a key component have been evaluated and selected as an approach to attain optimal production.     

Adsorption and bonding energy indexes for phosphorus in four soils of northeast thailand

Abstract

Four important soils of Thailand were studied in the laboratory and greenhouse to determine the relationship between the relative uptake of P by tomato plants, the P in the presence of added P absorption maximum, and the bonding energy. The relative uptake of P was higher in soils which had low initial available soil P and was lower in soils that had an initially high P status. The sorption of P was less in those soils which had the higher initial water‐soluble P. Generally, as the absorption maximum and bonding energy of the soils decreased, the relative yield response to added P increased.     

Effect of nitrogen application on the bromide content of lettuce grown under glass

Abstract

Lettuce (Lactuca sativa L.) collected from eleven trials with different rates of application of ammonium nitrate limestone was analysed for bromide. Nitrogen application (0–2.6 kg N/100 m²) decreased the bromide content of the lettuce in most trials. This decrease varied from 0 to 50%, with 27% as the average. A correlation was found between the bromide content of the crop and that of the soil extract at the conclusion of the trials. The correlation could be improved by calculating a multiple regression equation which included the nitrate content of the soil extract.     

Growers problems with hydroponics

Growers problems with production of vegetables in soilless cultural systems are primarily caused by nutrient deficiencies or toxicities that may not necessarily be due to improper preparation of the nutrient solution. Pythium fungus disease on the roots has caused crop failures of tomatoes and cucumbers in NFT during warm weather.     

5种植物精油对樱桃番茄常温保鲜效果的影响

以千禧樱桃番茄为供试果蔬,研究5种植物精油处理对其常温保鲜的效果,筛选出具有较高保鲜活性的植物源材料,以期充分利用我国的天然植物资源,为植物精油在樱桃番茄果实保鲜上的应用提供理论依据.结果表明,以失重率、好果率为指标综合评定,薰衣草精油、松红梅精油、红百里香精油、迷迭香精油、罗勒精油这5种精油对樱桃番茄的适宜处理浓度均为500μL·L-1.研究樱桃番茄贮藏期间的各项生理生化指标,发现红百里香精油可以有效延缓樱桃番茄的衰老,在20℃贮藏25d后好果率为68.34％,仍能保持较好的风味和硬度,维持果实细胞膜透性,抑制MDA积累,显著延缓了可溶性固形物、可滴定酸、抗坏血酸含量的降低.     

番茄差压预冷速度影响因素的试验研究

自行研制了差压预冷模拟试验台,测试了不同条件下番茄的中心温度,分析了不同送风温度、送风速度、开孔大小和番茄摆放方式对预冷速度的影响,揭示了番茄差压预冷的冷却规律,为番茄差压预冷系统的设计提供理论依据。