The effect of intracanopy lighting on cucumber fruit yield—Model analysis

Intracanopy lighting is a recently developed supplementary lighting technique for high-wire grown vegetable production in greenhouses where a part of the lamps is mounted within instead of above the canopy. A potentially higher yield using intracanopy lighting compared with top-lighting, is based on three assumptions: (1) increased light-absorption by the crop; (2) a higher photosynthetic light use efficiency due to a more homogeneous vertical light distribution; (3) a preserved photosynthetic capacity of leaves deeper in the canopy. We used an explanatory crop model to quantify the relative importance of these assumptions for a cucumber crop during an experiment in winter in the Netherlands (Trouwborst et al., 2010). Photosynthesis and yield data of this intracanopy lighting experiment with light-emitting diodes (34% of supplemental PAR) in combination with top-lighting (66% of supplemental PAR) were used to parameterise our model. In that study intracanopy lighting did not result in an increased yield compared with 100% top-lighting due to extreme leaf curling and a lower dry matter partitioning to the fruits. Our model predicted an 8% increase in fruit yield for the intracanopy lighting treatment if there were to be no leaf curling and no lower dry matter partitioning. This increase can be largely explained by the change in light distribution and light absorption. The model further revealed unexpectedly large consequences of the lower dry matter partitioning to the fruits whereas the negative effect of leaf curling was small. The direct effect of a greater A_max at deeper canopy layers was slightly positive. The last however might have indirectly caused the greater partitioning to the leaves as the greater A_max was associated with a preserved leaf mass per area. Solutions for this problem are discussed. Our explanatory model allowed us to disentangle the interacting effects of intracanopy lighting on fruit yield. Overall, intracanopy lighting has been shown here to potentially increase the assimilation light use efficiency.     

日光温室不同矮蔓型西葫芦的干物质生产与分配研究

对4个不同矮蔓型西葫芦品种的干物质生产与分配进行研究,结果表明,半矮蔓与矮蔓西葫芦品种各器官干物质含量没有显著差异,根、茎、叶、果干物质含量分别为:9%、6%、12%、5%;全生育期群体生长率(cropgrowth rate,CGR)半矮蔓品种平均为17.2g/(m2·d),而矮蔓品种为12.5g/(m2·d),半矮蔓品种是矮蔓品种的1.38倍;苗期、结果初期、结果中期、结果后期的当前干物质生产量半矮蔓品种分别是矮蔓品种的1.07、1.28、1.26、1.91倍,后期干物质生产衰减与矮蔓品种的早衰存在着相互依存关系;当前干物质的分配率营养器官与生殖器官的比半矮蔓品种为2.7∶1,矮蔓品种为2.1∶1;干物质累积值半矮蔓品种是矮蔓品种的1.4倍,果实干质量累积值半矮蔓品种是矮蔓品种的1.27倍,半矮蔓品种干物质向果实的分配率约为30.8%,矮蔓品种约为34.7%,单位面积干物质生产量的提高是半矮蔓品种果实干质量高于矮蔓品种的主要原因。     

模型模拟灌水量对日光温室袋培番茄产量、品质及水分利用效率的影响

采用番茄叶面积指数模型结合水分吸收模型计算番茄植株每日需水量的方法,研究不同灌水量(CK,经验型灌水量;W1,模型计算灌水量;W2,低于模型计算15%灌水量;W3,低于模型计算25%灌水量)对日光温室基质袋培番茄生长、产量、品质及水分利用效率的影响。结果表明:番茄植株的株高、茎粗、果实横径、光合速率和地上部干质量等随灌水量的减少呈下降趋势;对照的单株产量最高,为4.66kg,分别比W1、W2和W3处理增产4.3%、23.3%和47.9%,但与W1处理差异不显著;适宜降低灌水量可增加果实可溶性糖含量、糖酸比及VC含量,果实品质提高,其中W3处理最优,W1处理次之;W1处理的水分利用率最高,为51.76kg·m-3,分别比对照、W2和W3处理高出10.3%、0.6%和5.9%。在本试验条件下,W1处理在保证番茄产量和品质的基础上,显著提高了水分利用效率,该复合模型适合日光温室基质袋培番茄水分管理应用。     

栽培槽大小对日光温室架式栽培番茄生长发育、水肥利用和产量品质的影响

利用封闭式循环供液高架栽培系统,研究了栽培槽大小(横切面宽度×深度:20cm×10cm,20cm×15cm,20cm×20cm)和钵栽(直径12cm×高10cm,基质容积1L)对架式栽培番茄(3穗果摘心)生长发育、水肥利用及产量品质的影响。结果表明:与钵栽相比,槽栽促进番茄植株生长,增加产量,但开花和采收时间延迟,果实品质下降,水肥利用效率降低;随着栽培槽体积的增大,植株生长旺盛,干物质积累量增加,但水肥利用效率降低,果实品质下降,不同大小栽培槽处理间水分利用效率和单株产量差异不显著。综合产量、品质及水肥利用效率等指标,番茄架式栽培槽大小以20cm×10cm为宜。     

Effects of deficit irrigation on biomass,yield, water productivity and fruit quality of processing tomato under semi-arid Mediterranean climate conditions

Processing tomato is a high water demanding crop, thus requiring irrigation throughout growing season in arid and semiarid areas. The application of deficit irrigation (DI) strategies to this crop may greatly contribute to save irrigation water. A two-year study was carried out in order to assess the effects of DI upon water productivity, final biomass, fruit yield and some quality traits of open-field processing tomato cv. Brigade in a typical semi-arid Mediterranean environment of South Italy. Four irrigation treatments were studied: no irrigation following plant establishment (V0); 100% (V100) or 50% (V50) evapotranspiration (ETc) restoration up to fruit maturity, 100% ETc restoration up to flowering, then 50% ETc restoration (V100-50). Total dry biomass accumulation was significantly depressed by early soil water deficit in V0; irrigation at a reduced rate (50% ETc) from initial stages (V50) or from flowering onwards (V100-50) did not induce any losses in final dry biomass. The marketable yield did not significantly differ among plots irrigated, but an averaged irrigation water saving of 30.4% in V100-50 and 46.2% in V50 was allowed as compared to V100. Marketable yield was negatively affected by the early water shortage in V0, due to the high fruit losses (>44%). The effects of DI on fruit quality were generally the converse of those on fruit yield. DI improved total soluble solids content, titratable acidity and vitamin C content. Water use efficiency was positively affected by DI, suggesting that the crop does not benefits from the water when this last is supplied to fulfil total crop requirements for the whole season. Yield response factor, which indicates the level of tolerance of a crop to water stress, was 0.49 for total dry biomass (Kss) and 0.76 for marketable yield (Ky), indicating that in both cases the reduction in crop productivity is proportionally less than the relative ET deficit. In conclusion, the adoption of DI strategies where a 50% reduction of ETc restored is applied for the whole growing season or part of it could be suggested in processing tomato, to save water improving its use efficiency, minimizing fruit losses and maintaining high fruit quality levels. This aspect is quite important in semi-arid environments, where water scarcity is an increasing concern and water costs are continuously rising.     

The effects of pre-harvest dehydration on the composition of once-over harvested sweet paprika

When paprika fruits (Capsicum annuum L.) were allowed to dry in the sun, on the plant itself, before harvest, there was a considerable increase in the dry matter content of the subsequently harvested fruit, along with a decrease in the total fresh yield. The dry matter yield did not vary during the drying period, but the colour intensity of the fruit increased continuously. Early cessation of irrigation accelerated the drying rate and intensified fruit colour, but lowered the total dry matter yield.Removal of seeds, placenta parts and stalk after harvest increased fruit colour intensity but lowered yields.Leaving fruit to dry in the sun before harvest resulted in a considerable saving in transport and storage volume, as well in the amount of energy required otherwise to dry the fruit in the dehydration plant. It also opens up possibilities of once-over mechanized harvesting of high quality fruit.     

麦田间作春甘蓝的生长发育特性

麦田间作春甘蓝，小麦对间作甘蓝产生遮荫，使其田间光照显著减弱，地温降低、湿度增大。与单作甘蓝相比，间作甘蓝生长发育特性主要表现为：球叶合抱力下降，球叶数减少，外叶数增多，同时叶片光合速率降低，总干物质积累减少，尤其是向叶球的干物质分配减少，最终经济产量较单作降低２５．７％。提高间作甘蓝产量的关键是采用早熟品种和早熟栽培措施     

影响鸭梨产量品质的外界因素分析

对河北省不同生产基地鸭梨的产量、果实品质因子和外界因素进行了调查,用逐步回归分析法进行统计,以探讨鸭梨产量和果实品质与外界因素之间的关系。结果表明:土壤速效钾含量和灌水量对形成产量有较大的正效应;叶果比对产量有较小的负效应。生长季的降雨量对果实可溶性固形物含量有较大的负效应;叶果比对果实可溶性固形物含量是正效应。土壤有机质含量对果实单果重有较大的正效应。各项因子与鸭梨产量、单果重和可溶性固形物含量的相关系数均未达到差异显著水平。在保证果实可溶性固形物含量11.0%以上,667m2产量在3 500kg左右的水平,壤土类型、有机质含量在4.6g/kg以上的果园,生长季降水量在530.9～554.9mm的情况下,全年灌水量在150mm左右,即可满足梨树对水分的需求。     

河北省苹果园生草现状及土壤-树体-果实的综合效应

为明确河北省苹果园行间生草现状,探究草种适应性,为河北省果园生草栽培技术的推广与应用提供依据。采用调研的方法探究河北省果园行间生草的现状;在邢台市浆水镇富士苹果园,设置清耕、苜蓿、白三叶和自然生草4个处理,测定土壤有机质、无机氮、全氮、有效磷、速效钾、储水量和土壤酶活性等土壤性状,分析叶绿素、叶面积和新梢长等树体生长指标以及产量、果实品质。结果表明,河北省果园以清耕管理为主,生草园占31.96%,其中自然生草园占25.77%,人工生草园占6.19%;自然生草园草种选择更多样化;果农对生草认知缺乏且获知途径单一。自然生草显著提高0～20 cm和20～40 cm土壤有机质的积累,分别为15.46 g/kg和8.85 g/kg;苜蓿与白三叶显著增加了0～20 cm土层土壤无机氮、有效磷、速效钾含量,且对0～40 cm土层储水量有显著影响。白三叶与自然生草显著提高叶片叶绿素SPAD值,苜蓿与自然生草则显著增加了叶面积,苜蓿与白三叶显著增加了新梢长,连续6年生草老园叶绿素SPAD值(58.96)、叶面积(18.57cm²)以及新梢长(28.00 cm)均显著高于其他处理。苜蓿、白三叶与自然生草显著增产7.21%～13.40%。连续6年生草老园果实Vc(182.20 mg/kg)和可溶性糖(16.93%)显著高于各处理,可滴定酸(0.309%)显著低于清耕。河北省生草技术普及度低,行间种植苜蓿与白三叶能改善土壤性状、促进树体生长,改善果品品质、增加果品产出,因此推荐河北省苹果园种植豆科植物苜蓿和白三叶。     

茄子不同群体结构光合特性、干物质分配及其对产量的影响

 以嫁接茄子为试材, 采用4. 1 、4. 8 、5. 5 万株·hm^{- 2} 3 种密度和双杆整枝、自然整枝, 在日光温室吊绳栽培, 研究不同群体结构对光合特性、干物质分配及产量的影响。结果表明: 双杆整枝的功能叶光合速率高于自然整枝, 且各层次光合产物分布均匀, 根系生长较旺盛, 是增产的主要原因。茄子产量与中下部功能叶片光合速率关系密切, 在试验范围内密度越小, 中下部叶片水分利用效率和蒸腾速率越高, 光合速率越高, 呼吸消耗小, 总产量也越高。