绿洲生态条件下氮磷肥配施对冬小麦干物质分配及产量的影响

在西北绿洲生态条件下,设165 kg·hm-2(N1),225 kg·hm-2(N2)两个氮素(纯氮)水平和105 kg·hm-2(P1)、165 kg·hm-2(P2)两个磷素(P2O5)水平共4个处理,研究了氮磷配施对冬小麦产量及干物质积累及分配、灌浆特性的影响。结果表明:N2P1、N2P2具有较高的籽粒产量,分别为7 644.73、7 686.25 kg·hm-2,同时,水分利用效率(WUE)也较高,分别为11.67、11.49 kg·hm-2·mm-1;千粒重和穗粒数随施氮量增加而提高,磷对籽粒产量构成要素影响不显著;氮、氮和磷互作对籽粒平均灌浆速率(V)、最大灌浆速率(Vmax)、有效灌浆持续期粒重增加值(Ws)和有效灌浆持续期灌浆速率(Vs)均有显著影响,但影响籽粒重量的主要因素是Vmax;氮、磷及氮和磷互作对不同器官干物质积累及其分配影响在不同生育时期表现不一。     

春玉米干物质积累与转运对种植密度的响应

以西辽河平原主推的玉米品种郑单958、伟科702为试材,设4.5万株·hm-2(D1)、6.0万株·hm-2(D2)、7.5万株·hm-2(D3)、9.0万株·hm-2(D4)和10.5万株·hm-2(D5)5个种植密度,通过2012、2013年两年的田间试验,研究了不同品种春玉米干物质积累与转运对种植密度的响应。结果表明,两品种产量、物质积累与转运随种植密度的变化规律一致。产量随种植密度的增加先升后降,在D4密度下达到最高,郑单958为13.945 t·hm-2(2012年)和13.981 t·hm-2(2013年),伟科702为16.088 t·hm-2(2012年)和14.606 t·hm-2(2013年)。随种植密度增加,吐丝前干物质积累量增加,吐丝后先升后降;积累率总体表现为吐丝前升高,吐丝后降低;对籽粒贡献率随种植密度增加先升后降,吐丝后随密度增加而增加。随种植密度的增加,叶和茎鞘的转运量增加。茎鞘转运率增加而叶转运率降低;叶、茎鞘转运对籽粒贡献率在D4密度下最大。随种植密度增加,完熟期叶和穗部营养体分配比例降低,茎鞘的分配比例总体增加,籽粒分配比例先增后降。穗粒数和千粒重均随种植密度的增加而降低。     

高寒地区芸豆氮肥与密度优化组合模式研究

以黑龙江省北部主栽芸豆品种英国红为试验材料,分析了氮肥和密度对生育期、形态特征、产量、产量构成因素、商品与营养品质等方面的影响。结果表明:N肥会显著增加各个生育时期和生育期的天数,低密度时差异不显著,超过20万株·hm-2差异显著。单株荚数、单荚粒数和百粒重随着密度的增加而降低,各氮肥处理间差异不显著;芸豆的商品率随着密度的增大而降低;N肥45 kg·hm-2和密度10万株·hm-2的组合脂肪含量最大为1.51%,各处理间差异显著;蛋白质最大值出现在N肥60 kg·hm-2和10万株·hm-2的密度与氮肥组合上,最大值为14.55%,与N肥45 kg·hm-2和10万株·hm-2组合差异不显著,与其它组合间差异显著;N30 kg·hm-2和20万株·hm-2组合产量最高,为3 418.56 kg·hm-2,与N肥45 kg·hm-2和15万株·hm-2组合产量(3 417.46 kg·hm-2)相当,与其他组合间差异显著。综合种植的经济效益和品质分析,最为理想栽培模式为N肥45 kg·hm-2和15万株·hm-2组合。     

基于APSIM模型的地膜覆盖与露地种植条件下旱地小麦灌浆过程模拟

准确模拟小麦籽粒干物质积累过程可为调控小麦生产提供技术支持。基于APSIM模型模拟数据和大田实测数据同步研究旱地冬小麦籽粒干物质积累过程,并在模型验证的基础上分析积温对小麦籽粒干物质积累过程的影响。APSIM-Wheat模型模拟地膜覆盖和露地种植在灌浆期各阶段粒重和籽粒灌浆速率的决定系数大于0.92,归一化均方根误差小于16.25%,有效性指数大于0.91,表明APSIM-Wheat模型在研究区模拟小麦灌浆过程具有较好的拟合度和适应性。地膜覆盖种植优于露地种植,两年度模型模拟地膜覆盖籽粒干物质日积累量模拟值高于露地5.23%,田间实测地膜覆盖的最大灌浆速率平均高于露地10.46%,快增期平均灌浆速率高于露地13.68%,千粒重平均高于露地2.50%。Logistic进一步分析表明,地膜覆盖种植有利于提前最大灌浆速率的时间,减少灌浆渐增期、缓增期的持续时间;其次,积温通过影响籽粒干物质日积累量进而影响灌浆速率,在灌浆期大气日积温、土壤日积温与籽粒干物质日积累量均呈极显著正相关关系。     

西北旱塬区不同株型玉米增密对产量的影响

为了探明增密对西北黄土旱塬区玉米产量的影响,于2011-2014年在农业部西北旱作区作物营养与施肥科学观测实验站进行田间试验,选取不同株型(紧凑型、平展型)玉米品种5个,每个品种设4个密度梯度,分析了不同株型玉米产量、干物质、根冠比、灌浆速率等指标。结果表明:不同株型玉米品种,随着密度增加田间耗水量差异不显著;紧凑型玉米品种产量大于平展型,在同等栽培条件下,平展型最佳播种密度为7.07万株·hm~(-2),紧凑型较之增加0.91万株·hm~(-2),产量增加2 085.9 kg·hm~(-2);密度增加单株干物质和根冠比均呈减小趋势,两种株型玉米品种规律一致,在灌浆和成熟期,紧凑型玉米品种7.5、9.0万株·hm~(-2)根冠比基本一致,平展型玉米品种密度为6.0万株·hm~(-2)干物质量最高(32 310 kg·hm~(-2)),紧凑型在7.5万株·hm~(-2)时为29 226 kg·hm~(-2),干物质积累量平展型大于紧凑型;灌浆速率参数平展型较紧凑型玉米品种最大灌浆速率高0.18 g·d-1,平均灌浆速率高0.03 g·d-1,灌浆持续期相差不大;低密度较高密度灌浆速率快0.01 g·d-1,但灌浆持续期延长5~15 d。西北旱塬区选择紧凑型较平展型玉米品种播种密度增加9 000株·hm~(-2),有利于优化群体结构,增加玉米产量。     

种植密度对糜子生长发育及产量影响

采用完全随机区组试验设计,以河曲大红黍为材料,设定6个密度处理,研究不同种植密度对糜子的株高、茎粗、分蘖数等形态指标,单株叶面积、叶绿素相对值、光合速率等光合指标,干物质积累量,产量构成因素及产量的影响;运用非线性回归分析的方法,对密度与作物产量的经验模型进行模拟.结果表明:种植密度超过一定范围值时,随着密度的增加,株高增大,茎粗变细,分蘖数减少和光合生理指标均降低,穗重、穗粒重和有效穗粒数逐渐减少,干物质积累量减少,产量降低;产量随着种植密度增加呈先升后降的趋势,二次曲线模型的方程式为Y=176.78471+ 11.51879X-1.29607X2,理论最适密度范围为4万株/666.7m2-5万株/666.7m2.     

栽培密度对新疆蓖麻产量构成的影响

为探讨盐碱地栽培密度对蓖麻生长和产量变化的影响,研究了4种栽培密度下株高、茎粗、单株有效穗数、百粒重等产量相关因素。结果表明:随着栽培密度的增加,蓖麻产量增加,单株平均穗数降低,平均株粒重降低。密度从31 250株·hm~(-2)增加到41 667株·hm~(-2),产量增加不显著。蓖麻籽百粒重在31 250株·hm~(-2)时达到最大,为30.85 g。主穗出籽率在31 250株·hm~(-2)时达到最大值87.7%。主穗产量在单株总产中的占比在31 250株·hm~(-2)时达到最高,一级穗产量在41 667株·hm~(-2)时最高。蓖麻在41 667株·hm~(-2)的栽培密度下获得最高产量。干物质向生殖器官的分配比例在25 000株·hm~(-2)时达到67.3%。     

不同肥料配比对旱地胡麻产量及品质的影响

大田旱作条件下,研究了氮磷配肥对胡麻产量、品质和农艺性状的影响。结果表明,氮磷配施均能增加胡麻产量,当氮肥用量一定(N 30~60 kg·hm-2)时,增施磷肥(P2O522.5~90 kg·hm-2)能使胡麻籽粒产量较对照增加50.00%~84.23%;当磷肥用量一定(P2O530~120 kg·hm-2)时,增施氮肥同样促进胡麻产量,但低磷高氮肥和高磷高氮肥反而不利于胡麻产量的增加;氮肥效果比磷肥明显,其中以N2P3处理(N 60 kg·hm-2,P2O567.5 kg·hm-2)产量最大,达到1 719.44 kg·hm-2。增施氮肥能够增加胡麻的株高、工艺长度、千粒重、分茎数、主茎分枝数和单株有效果枝数,高磷肥反而不利于胡麻农艺性状的改善。氮磷配施使胡麻棕榈酸含量较对照增加0~5.62%,油酸的含量较对照增加0~4.06%,施用氮肥可增加胡麻的亚油酸和亚麻酸含量,而高磷肥反而降低了亚油酸和亚麻酸含量。     

可降解地膜覆盖和有机无机氮肥配施对胡麻干物质和产量的影响

通过田间定位试验,研究了不覆膜、普通地膜和0.008、0.010、0.012 mm厚度的可降解地膜以及不施氮、单施化学氮肥(120 kg·hm~(-2))、化学氮肥与有机氮肥配施(120 kg·hm~(-2),2/3化学氮肥,1/3有机氮肥)对胡麻干物质积累、籽粒灌浆以及经济产量的影响。结果表明,可降解地膜和普通地膜覆盖胡麻生育期的差异较小(≤2 d),0.012 mm可降解地膜对生育进程的影响最接近普通地膜。普通地膜对干物质积累的促进作用较可降解膜提高了12.88%～160.22%;0.012 mm可降解地膜对胡麻生长的促进作用更接近于普通地膜,其干物质量较普通膜的降幅(11.41%～27.92%)低于其余2种降解膜(16.55%～61.57%);0.012 mm的可降解膜与普通地膜灌浆速率无显著差异。有机无机氮肥配施较单施化肥对胡麻生长的促进作用显著,营养生长阶段中后期的干物质积累量增加了11.69%～16.44%,但对灌浆速率的提升作用较单施化肥小。3种可降解地膜具有与普通地膜同等的增产作用,覆膜后平均增产19.18%;施氮提高了籽粒产量,有机无机氮肥配施和单施化肥间无显著差异。覆膜和施肥仅对干物质积累具有显著的交互作用。试区胡麻生产上可用0.012 mm的可降解地膜代替普通地膜。     

钾肥和密度对胡麻干物质及钾积累转运和产量的影响

采用田间试验,以陇亚杂1号胡麻品种为材料,研究了3个钾肥用量(K2O):0,45 kg·hm~(-2)和90 kg·hm~(-2)和3个密度水平:4.5×10~6,7.5×10~6株·hm~(-2)和10.5×10~6株·hm~(-2)对胡麻干物质和钾养分积累、转运、子粒产量以及子粒中钾积累量的影响。试验结果表明,钾肥和密度促进了胡麻干物质及钾养分的积累和转运,随施钾量和密度的增加,胡麻干物质和钾积累量增加,转运量升高,来自叶和蒴果皮及茎中干物质和钾对子粒的贡献率降低,子粒产量来自花后干物质积累量增加,子粒中钾来自花后钾积累的量增加。在施钾45 kg·hm~(-2),密度7.5×10~6株·hm~(-2)处理下,花前营养器官干物质和钾转运量最高,分别为1 183.56 kg·hm~(-2)和30.28 kg·hm~(-2),对子粒贡献率最低,分别为40.28%和58.72%,子粒产量和子粒钾最高,分别为2 938.33 kg·hm~(-2)和51.57 kg·hm~(-2),与不施钾,密度4.5×10~6株·hm~(-2)处理相比较,分别提高了44.32%和49.43%。在本试验区同等环境条件下种植胡麻,以施钾45kg·hm~(-2),密度7.5×10~6株·hm~(-2)为宜。     

Hymenopteran Parasitoids on Fruit-infesting Tephritidae (Diptera) in Latin America and the Southern United States: Diversity, Distribution, Taxonomic Status and their use in Fruit Fly Biological Control

We first discuss the diversity of fruit fly (Diptera: Tephritidae) parasitoids (Hymenoptera) of the Neotropics. Even though the emphasis is on Anastrepha parasitoids, we also review all the information available on parasitoids attacking flies in the genera Ceratitis, Rhagoletis, Rhagoletotrypeta, Toxotrypana and Zonosemata. We center our analysis in parasitoid guilds, parasitoid assemblage size and fly host profiles. We also discuss distribution patterns and the taxonomic status of all known Anastrepha parasitoids. We follow by providing a historical overview of biological control of pestiferous tephritids in Latin American and Florida (U.S.A.) and by analyzing the success or failure of classical and augmentative biological control programs implemented to date in these regions. We also discuss the lack of success of introductions of exotic fruit fly parasitoids in various Latin American countries. We finish by discussing the most pressing needs related to fruit fly biological control (classical, augmentative, and conservation modalities) in areas of the Neotropics where fruit fly populations severely restrict the development of commercial fruit growing. We also address the need for much more intensive research on the bioecology of native fruit fly parasitoids.     

Brief Guide for Authors

正Journal of Arid Land(JAL)is an international journal(ISSN 1674-6767;CN 65-1278/K)for the natural sciences,sponsored by the Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences and Science Press.It is published by Science Press and Springer-Verlag Berlin Heidelberg bimonthly.JAL publishes original,innovative,and integrative research from arid and semiarid regions,ad     

The parasitoid complex ofLiriomyza cicerina on chickpea (Cicer arietinum)

Liriomyza cicerina (Diptera: Agromyzidae) is an important pest on chickpea in Turkey. The objective of this study was to determine the parasitoids and rates of parasitism ofL. cicerina on chickpea (Cicer arietinum L.) during the 2005 and 2006 seasons in ?anl?urfa province, Turkey. Leaves with mines were sampled weekly and kept in the laboratory to observe and count emerging leafminer and parasitoid adults. Eight parasitoid species were collected: the braconidsOpius monilicornis Fischer andOpius tersus Foerster and the eulophidsDiaulinopsis arenaria (Erdös) andNeochrysocharis formosa (Westwood), which occurred in both the winter and summer seasons;Diglyphus crassinervis Erdös,Neochrysocharis ambitiosa Hansson,Neochrysocharis sericea (Erdös) andPediobius metallicus (Nees), which occurred only in the summer growing areas.Diaulinopsis arenaria was the predominant parasitoid with 4–7.7% parasitism rate whileN. ambitiosa andO. monilicornis were the second and third most predominant species. The results of these trials show that sinceDia. arenaria occurred throughout every season, it could potentially be used for control of the leafminerL. cicerina.     

Plant–herbivore asynchrony necessitates augmentative releases of the exotic beetle,Zygogramma bicolorata,to enhance the biological control of P arthenium hysterophorus

Systematic information on the quantitative impact of Z ygogramma bicolorata on the biology of P arthenium hysterophorus is crucial as the seeds of this weed continue to germinate from the accumulated soil seed bank throughout the year in the form of different germinating flushes, while the activity of the beetle ceases during winter as it enters diapause. Therefore, plant–herbivore interactions need to be explored to develop predictions of the overall impact of the introduced beetle on the weed. The findings revealed that defoliation by Z . bicolorata had a significant impact on the plant height, density and flower production in flushes F ₃, F ₄ and F ₅, but not in F ₁ and F ₂ that exhibited longer periodicity, profuse branching, a longer flowering period and maximum flower production and contributed mostly to the existing seed soil bank. Therefore, total depletion of the existing soil seed bank was not possible. Consequently, the effect of augmentative field releases of laboratory‐reared beetles was explored on F ₁ and F ₂ in February for three consecutive years (2011–2013). Before initiating the trial, random soil samples were taken from the plots that were assigned to the paired treatments (i.e. with the beetle and without the beetle [insecticide‐treated]) and it was found that the seed bank in those samples did not differ. The single release of Z . bicolorata adults at five per plant at the six‐leaf stage significantly reduced the soil seed bank, compared to without the biocontrol agent, irrespective of the flushes at the end of the season.     

Effects of the saprophytic leaf mycoflora on growth and productivity of winter wheat

The effects of the saprophytic mycoflora and its interference with cereal aphids on growth and yield of winter and spring wheat was studied in field experiments in 1980, 1981 and 1982.Yields varied between 5000 and 8000 kg dry matter of kernels per ha. The effect of the saprophytic mycoflora on yield was determined in different treatments: A) no control measures against cereal aphids and saprophytic and necrotrophic fungi, B) no control of cereal aphids, control of saprophytic and necrotrophic fungi, C) control of cereal aphids and control of saprophytic and necrotrophic fungi, D) control of cereal aphids and stimulation of saprophytic mycoflora and E) control of cereal aphids, no control of saprophytic and necrotrophic fungi nor stimulation of saprophytic mycoflora.Considerable differences in top densities of saprophytic mycoflora (10 times as large in A and D as in B and C) were determined. The consequences of these differences for the growth and productivity of wheat were minor. A negative effect of saprophytic mycoflora on the yield could not be detected in 1981 and 1982, whereas a small positive significant effect was found in 1980. This stimulation may have been due to competition between necrotrophic fungal pathogens and saprophytic mycoflora. As a result of favourable weather conditions necrotrophic fungal pathogens were very numerous in 1980 and could form an important yield reducing factor. Yield levels may effect the importance of the necrotrophic and saprophytic mycoflora as yield reducing factors. Additionally, in the presence of aphid honeydew captafol was found to be relatively ineffective against saprophytic fungi.     

Relationship Between Production of the Phytotoxin Prehelminthosporol and Virulence in Isolates of the Plant Pathogenic Fungus Bipolaris sorokiniana

A gas chromatographic method was developed to quantify the phytotoxin prehelminthosporol, which is a sesquiterpene metabolite of the plant pathogen Bipolaris sorokiniana. The toxin was extracted from mycelium or culture filtrates, pre-cleaned using solid phase extraction, and analyzed by gas chromatography as a trimethylsilyl-derivative. The detection limit of the method was 5ngl^–1 (signal to noise ratio 4:1) which corresponds to ca. 15ng prehelminthosporol per mg dry weight of mycelium or 15ng prehelminthosporol per ml culture filtrate. The total amount of prehelminthosporol (mycelium plus culture filtrate) increased with cultivation time when examined in six isolates of B. sorokiniana after 6, 9, 12 and 15 days of incubation. The screening experiment of 17 isolates for prehelminthosporol production after 8 days of incubation revealed significant differences in the toxin production between the isolates. The isolates with low toxin production had lower virulence towards barley roots compared to those with higher production of the toxin. However, the virulence did not increase with prehelminthosporol level among the high producing isolates. Prehelminthosporol was also analyzed in a number of related Bipolaris and Drechslera species. In addition to B. sorokiniana, three out of six Bipolaris species (B. setariae, B. zeicola, B. victoriae) produced prehelminthosporol, which indicates that ability to produce prehelminthosporol is conserved among closely-related Bipolaris species.     

Effect of botanical insecticides and bacterial toxins on the gut enzyme of the rice leaffolderCnaphalocrocis medinalis

The effect of botanical insecticides and bacterial toxins on gut enzyme activity of larvae of the rice leaffolderCnaphalocrocis medinalis (Guenée) (Insecta: Lepidoptera: Pyralidae) was investigated. Gut enzyme activities were affected by botanical insecticides and bacterial toxin individually and in combination. When fed a diet of rice leaves treated with botanical insecticides and bacterial toxins, in bioassays the activities of gut tissue enzymes — acid phosphatases (ACP), alkaline phosphatases (ALP) and adenosine triphosphatases (ATPase) — of rice leaffolder larvae were affected. When combined, the effect was more severe at a low concentration. Larvae that were chronically exposed to botanical insecticides and bacterial toxins showed a reduction in weight (59–89%) and exhibited a significant reduction in ACP, ALP and ATPase activities. The combination ofBacillus thuringiensis kurstaki and botanical insecticides caused a decrease of twofold in enzyme activity even at reduced concentration. A synergistic effect was found when botanical insecticides and bacterial toxins were combined at low doses. These effects were most pronounced in early instars. Clear dose-response relationships were established with respect to enzyme activity. In conclusion: (i) biopesticides are relatively safe and biodegradable; (ii) a synergistic effect of botanical insecticides and bacterial toxins was found; (iii) less expensive, readily available and naturally occurring biopesticides could be an alternative for organic and inorganic pesticides in controlling RLF. http://www.phytoparasitica.org posting Sept. 28, 2004.