Effects of shade regimes and planting geometry on growth,yield and quality of the natural sweetener plant stevia (Stevia rebaudiana Bertoni) in north-western Himalaya

During 2008 and 2009, field experiments were conducted at the research farm of CSIR-Institute of Himalayan Bioresource Technology, Palampur, India to assess the effect of shade levels (no shade, 25% shade, 50% shade, 75% shade) and plant geometry levels [30 × 15 cm (north–south, N–S), 45 × 10 cm (N–S), 30 × 15 cm (east–west, E–W) and 45 × 10 cm (E–W)] on the growth, yield and quality of stevia. Plant development was fastest in controls and slowest in stevia plants growing at minimum light (75% shade). These plants showed delayed bud formation and flowering. Significantly, higher dry leaf yield was recorded when the crop was grown under 25% shading than under 50 and 75% shade. Total steviol glycosides content decreased with increasing shade levels. All shade levels resulted in the same leaf-to-stem ratio, which was significantly higher than that obtained under ambient light. Plant geometry significantly affected the number of leaves and leaf dry weight plant^–1. During both years, dry leaf weight was highest in the wider row spacing (45 × 10 cm) than in the narrow row spacing (30 × 15 cm). Stevia spaced at 30 × 15 cm in an E–W direction recorded significantly higher total steviol glycosides at 2 months after transplanting (MAT).     

Bioorganic Nutrient Source Effect on Growth,Biomass, and Quality of Natural Sweetener Plant Stevia and Soil Fertility in the Western Himalayas

The effects of bioorganic nutrients on stevia were studied during 2011 and 2012 at Institute of Himalayan Bioresource Technology, Palampur, India. Bioorganic nutrient sources were evaluated in fourteen treatment combinations. Results showed that number of leaves plant^?1, leaf area plant^?1, and fresh and dry leaf biomass plant^?1 were significantly greater with the application of farmyard manure (FYM) 15 Mg ha^?1 + vermicompost (VC) 5 Mg ha^?1 + stevia seedlings treated with phosphorus-solubilizing bacteria (PSB) and azotobacter as compared to the control but plant height and the number of branches were not significantly affected by various treatments. This superior combination also resulted in considerably greater amounts of phosphorus (P) in stem (1.18 percent) and potassium (K) in leaf (2.39 percent). Stevia plants supplied with VC 7.5 Mg ha^?1 + stevia seedlings treated with PSB and azotobacter recorded greater stevioside (7.2 percent) and total steviol glycoside (8.4 percent). Application of organic manures in combination with biofertilizers enhanced soil organic carbon and available nutrient status of soil as compared to control.     

株行距配置连作对黄土旱塬覆膜春玉米土壤水分和产量的影响

探讨株行距配置调整后密度对旱地覆膜春玉米连作稳产和水分利用的影响,为旱地雨养区春玉米高产稳产栽培提供依据。试验于2014—2017年在黄土旱塬区甘肃省镇原县(35°30′N,107°39′E)进行,以紧凑型耐密高产春玉米品种"先玉335"为试验材料,设55,75 cm 2种等行距垄沟覆盖种植方式,6.0,7.5,9.0,10.5万株/hm~2 4个种植密度水平,采用裂区设计,连作定位观测。使用烘干法测定不同处理春玉米生育期0—200 cm土层土壤水分,研究黄土旱塬连作春玉米籽粒产量和土壤剖面水分变化。结果表明,在试验设计行距下,在干旱年份55,75 cm行距0—200 cm土层土壤剖面水分均有低湿区形成,2种行距40—200 cm土层最低含水率均出现在160 cm土层剖面,55 cm行距土壤含水量为8.9%,75 cm行距土壤含水量为8.7%,受降水及植株生育耗水的影响,20—120 cm土层土壤水分变化较为剧烈。不论降水年型如何,2种行距下0—200 cm土壤深层水分均未产生土壤干层,75 cm行距低湿区较55 cm行距随年份变化有不同程度扩大,但2种行距下7.5～10.5万株/hm~2相同密度耗水量没有显著差异。4年平均产量75 cm行距相同密度均高于55 cm行距,9.0万株/hm~2及以下种植密度处理稳产性较好,密度由低到高产量分别增加2.2%,5.8%,4.1%和3.0%,平均水分利用效率分别提升1.1%,5.9%,0.3%和-1.5%,不同行距相同密度产量和水分利用效率没有显著差异。研究表明,在黄土旱塬区55,75 cm行距配置7.5万株/hm~2种植密度连作具有稳定产量,并且不会导致土壤深层水分亏缺至产生土壤干层,是较为理想的连作稳产株行距配置种植模式。     

Production potential of Stevia rebaudiana (Bert.) Bertoni. under intercropping systems

Abstract

Stevia (Stevia rebaudiana[Bert.] Bertoni.) is a crop of recent domestication in many countries. The cultivation of this plant in hilly and frost-prone areas provides an opportunity for intercropping of various food crops since the crop undergoes winter dormancy in India. This was studied through intercropping (additive series) at two spacings of the main crop, namely, 45×45 cm and 60×45 cm. Wheat, barley, lentil and gobhi sarson were intercropped. Intercropping reduced the production of S. rebaudiana up to 50% when compared to sole cropping. However, a row spacing of 60×45 cm resulted in less competition than the former, although, single cropping of S. rebaudiana produced the maximum stevioside. Intercropping with wheat increased the stevioside content when compared to other intercrops. The introduction of wheat resulted in higher monetary benefits at 60×45 cm spacing. Results indicated that reduction in S. rebaudiana biomass was mainly due to overlapping of the emergence period of the main crop with rapid growth and development of the intercrops. In conclusion, to lower competitive effects, the intercrop needs to be early maturity. Identifying suitable varieties for intercropping should be the priority research area to increase the productivity of the system.     

种植密度对晋糯20号玉米产量和商品性的影响

为明确不同种植密度对晋糯20号玉米产量和商品性的影响,给该品种的推广提供技术支撑。采用二因素裂区设计,主区为4个密度梯度(4.50 万、5.25 万、 6.00 万、6.75 万株 /hm2),副区为4个行距(40 cm、50 cm、60 cm、40 cm+60 cm),共16个处理进行田间试验。结果表明:密度对晋糯20号鲜穗重、百粒重、穗长、产量影响极显著,行距对鲜穗重、产量影响差异,密度行距互作对产量影响极显著。随种植密度的增加,晋糯20号单株干物质呈下降趋势,鲜穗产量呈先增后降再增的变化趋势;密度为 5.25 万株/hm2 处理下,产量最高,穗长、穗质量和百粒重也表现较好,此密度下配40 cm+60 cm行距,鲜穗产量可达(13 992.90±142.50) kg/hm2,优级穗率最高,为92.5%。此外,密度对优级穗率影响显著,宽窄行可以提高优级穗率。建议在晋糯20号的种植过程中,采用 5.25 万株 /hm2 配40 cm+60 cm行距,可明显提高产量与商品品质。     

种植行距与灌水量对西北日光温室番茄生育和产量的影响

研究膜下滴灌番茄不同种植行距与灌水量对番茄生育及产量的影响,试验在大小行沟垄种植形式的基础上设置3种种植行距分别为L1(60cm)、L2(45cm)和L3(30cm);以蒸发皿累积蒸发量E为标准设置0.6E、0.8E、1.0E、1.2E共4个灌水水平,共12个处理。研究了不同种植行距与灌水量对番茄不同生育期生长生理指标及产量的影响,探讨了不同生长生理指标与产量间的关系。结果表明:低种植行距处理(L3),会造成植株徒长及过高的叶面积指数,抑制作物群体的光合生理活动,导致较低的产量和灌溉水利用效率。过低的灌水量(0.6E)会抑制番茄植株的光合生理活动,且随生育期的进行表现出明显的水分胁迫的累积作用。叶面积指数和净光合速率对产量的影响最为直接,提高作物的净光合速率是实现作物增产的重要途径;株高茎粗与叶面积指数间具有良好的回归关系(P=0.004 6),高茎粗低株高植株具有较为适宜的叶面积指数,有利于产量的形成。相较于产量最高的种植行距与灌水量组合L1-1.2E处理,L1-0.8E和L2-0.8E处理可在产量仅降低4.28%和9.00%的情况下提高灌溉水利用效率36.00%和29.29%。该结果为西北地区日光温室番茄科学种植与灌水提供依据。     

Productivity of two stevia varieties under reduced irrigation and fertilization inputs

A 3-year field study was conducted in central Greece to determine the productivity of two stevia [(Stevia rebaudiana (Bertoni) Bertoni] varieties (‘Morita’ and ‘Candy-stevia’) under normal and reduced irrigation (100% and 75% of the evapotranspiration) and fertilization [1:0.8:1.1 or 1:0.4:0.8 N:P:K ratio in the first year and only N fertilization (100% or 74% of the recommended rate) in the second and third years] inputs. Averaged across years, stevia cv. Morita achieved greater dry leaf yield (3.48 t ha^?1) than the cv. Candy-stevia (2.85 t ha^?1). Irrigation and fertilization inputs did not significantly affect stevia cv. Morita dry leaf and steviol glycosides (stevioside plus rebaudioside-A) yields; however, decreasing irrigation and fertilization caused slight reduction of cv. Candy-stevia yields. In cv. Morita leaves, the concentrations of stevioside and rebaudioside-A ranged from 5.97% to 7.78% and 3.73% to 4.79%, respectively, while the corresponding concentrations in cv. Candy-stevia leaves were 8.21–9.36% and 3.89–6.33%. Conclusively, both stevia varieties could achieve satisfactory dry leaf biomass and steviol glycosides yield, even when grown under reduced irrigation (at 75% of evapotranspiration) and reduced N fertilization (74% of the recommended rate). Thus, stevia could represent an alternative crop to tobacco in the Mediterranean conditions.     

Influence of staggered sown Spring sunflower (Helianthus Annuus L.) at varying intra–row spacing and applied–N on pre– and post–anthesis N dynamics and dry matter partitioning in Indo–Gangetic Plains Region

In current study, dry–matter accumulation (DMA), pre– and post–anthesis nitrogen (N) accumulation, N translocation (NT) and dry–matter partitioning by sunflower seeds was investigated under three sowing dates (January 20, February 10 & March 2), two intra–row spacings (30 & 24 cm) and four nitrogen doses (0, 45, 60 & 75 kg ha^–1) in two alluvial soils. Early sowing resulted in higher DMA and NT; leading to higher nitrogen use efficiency (NUE) that could be associated with higher pre–anthesis N accumulation. The closer intra–row spacing resulted in higher DMA by all plant parts except seed. Each graded N dose improved DMA, but improvement in dry–matter partitioning to seed was significant up to 60 and 75 kg N ha^–1 during 2014 and 2015, respectively owing to higher NT under respective treatments. NUE was highest at 60 kg N ha^–1 during both years.     

Effect of intercrop spacing and nitrogen fertilizer on establishment of Leucaena leucocephala in alley cropping

Abstract

One of the reasons for the low rate of adoption of alley cropping in the humid tropics is the problem of establishing the desired hedgerow trees. A split plot experimental design trial was set up to investigate the effects of 4 levels of nitrogen (N) fertilizer (0, 30, 60, and 120 kg N ha^‐1) on the growth of Leucaena leucocephala (Lam.) de Wit in an intercrop with maize. Maize (Ekona 83TZ SR Y) was planted at 0, 25, 50, and 75 cm from Leucaena hedgerows planted on the same day. Leucaena plants were harvested at 3, 6, and 12 months after planting for biomass yield, N uptake, nodulation and mycorrhization. Results showed that at 0, 25, and 50 cm Leucaena/maize intercrop, there was no effect of N on Leucaena biomass. Leucaena biomass yield at 75‐cm spacing compared favorably with the biomass of Leucaena sole cropped that had received 0, 30, and 60 kg N ha^‐1. Application of 120 kg N ha^‐1 to sole Leucaena increased biomass yield significantly above all the intercrop spacings. Measurement of the solar radiation in the system showed that there was a close relationship between the amount of solar radiation received by Leucaena and its biomass yield. Maize intercropped closer than 75 cm from Leucaena hedges reduced radiation received by Leucaena by 72% at 25 cm compared with 29% at 75 cm. This effect reduced Leucaena biomass yield at 25‐cm spacing by 50%. This study showed that Leucaena can be established in intercrop with maize, but it requires about 75‐cm intercrop spacing with crop and about 120 kg N ha^‐1 for good establishment. Leucaena/maize intercrop at 75‐cm spacing enables Leucaena to receive about 72% solar radiation and larger area to forage for plant nutrients.     

The effect of different nitrogen levels on yield and quality of stevia (Stevia rebaudiana bert.)

In the present work, the efficiency of different nitrogen doses (0, 50, 100, 150, and 200 kg ha^?1) on growth, yield, and quality of stevia (Stevia rebaudiana Bert.) was investigated in 2011–2013. The study was conducted in Antalya located in the Mediterranean Region of Turkey. Terra rossa type soil (LVx, FAO) characteristics of the experimental field were clay loam, with high amounts of lime (33,9%) and slightly alkaline (pH 7.7). The experiment was carried out in randomized block design with four replications. All the results were summarized as mean of three years. The highest fresh and dry biomass yields (26.75 t ha^?1 and 7.5 ha^?1, respectively) were obtained from 150 kg ha^?1 N dose and followed by 100 kg ha^?1 N dose (26.29 t ha^?1 and 7.24 ha^?1, respectively). Whereas the highest fresh and dry leaf yields (13.27 t ha^?1 and 3.82 t ha^?1, respectively) were realized in 100 kg ha^?1 N dose. Actually, all nitrogen doses gave higher biomass and leaf yields compared to the control. On the hand, major steviol glycosides (stevioside and rebaudioside A) in the leaf were not influenced by nitrogen levels. In conclusion, 100 kg ha^?1 N dose was found to be suitable for cultivation of stevia under field conditions.     

Influence of nitrogen levels and plant spacing on growth,productivity and quality of two inbred varieties and a hybrid of aromatic rice

A field investigation was conducted at the Indian Agricultural Research Institute's Research Farm during the kharif (wet) seasons of 2002 and 2003 in a split plot design with three replications, consisting of 27 treatments, namely, main plots: three varieties (PRH-10, Pusa Sugandh-3 and Pusa Basmati-1) and three plant spacings (20 × 10, 20 × 15 and 20 × 20 cm²) and sub-plots: three levels of nitrogen (0, 80 and 160 kg N ha^?1). The research results indicated that aromatic rice hybrid PRH-10 produced 33 and 6%, respectively, more grain yield than that of Pusa Sugandh-3 and Pusa Basmati-1. The appreciable higher grain yield of PRH-10 over Pusa Sugandh-3 and Pusa Basmati-1 was due to considerable improvement in most of the yield attributing characters. Application of 160 kg N ha^?1 recorded 23.7 and 26.1% more grain yield over no nitrogen application whereas it was 6.4 and 6.1% more over 80 kg N ha^?1, respectively, during first and second year of the experimentation. Wider plant spacing of 20 × 20 cm² and application of 160 kg N/ha recorded significantly higher hulling, milling and head rice recovery compared to closer spacing and zero nitrogen application.     

适宜机械收获株行距对黄土旱塬春玉米产量及水分利用效率的影响

通过黄土旱塬适宜机械化收获的不同株行距种植模式,研究不同株行距对春玉米产量和水分利用效率的影响,为该春玉米生产力提升提供理论依据。以紧凑型高产先玉335为供试品种,设置适宜机械化收获的55cm和75cm两种行距,通过株距调整设置6.0万株/hm~2,7.5万株/hm~2,9.0万株/hm~2,10.5万株/hm~2共4种栽培密度,于2014年和2015年连续2年定位试验,研究株行距对春玉米生长发育及水分利用效率的影响。结果表明:与55cm行距相比,75cm行距在干旱条件下能够有效延缓叶片衰老,成熟期依然具有较高的SPAD值、叶面积和叶面积指数,持绿性良好,为光合产物提高给予了支撑。不同株行距种植模式WUE表现不同,吐丝期WUEF基本随密度增加而增大,2种行距下2014年和2015年均是9.0万株/hm~2,10.5万株/hm~2密度处理WUEF较高;收获期2014年55cm行距9.0万株/hm~2,10.5万株/hm~2密度处理WUEH较高,75cm行距7.5万株/hm~2,10.5万株/hm~2密度处理WUEH较高,2015年2种行距下均为6.0万株/hm~2,10.5万株/hm~2密度处理WUEH较高。产量水分利用效率WUEY,55cm行距变化无规律,75cm行距随密度增加而增大。55cm行距和75cm行距均可以作为黄土旱塬区春玉米机械化收获种植行距,综合土壤水分变化、叶面积指数、SPAD值、收获指数、产量及水分利用效率等,75cm行距7.5万株/hm~2种植密度可以作为紧凑型春玉米试验区域内最佳株行距设置。     

Influence of tuber weight and cutting on growth and yield of safed musli (Chlorophytum borivilianum)

The present study was aimed to investigate the effect of different weight of planting material and cutting on safed musli cultivation. Tubers were divided into three weight categories (3, 6 and 9 g bulk^?1) and were either planted as whole or cut tubers. The plant growth and development were recorded at 60, 90 and 120 days after sprouting (DAS). The results showed that both factors had no interaction for all parameters measured. The sprouting percentage was not significantly different in all the treatments. The weight of planting materials used in the treatments had no influence on the overall plant growth and development. However, there was a significant difference observed between whole tuber and cut tuber treatments. At 90 DAS, tubers subjected to cutting encouraged the plants to produce the higher number of leaves (22.7) with improved total leaf area (642 cm²), fibrous root length (2795 cm) and tuber dry weight (7.8 g). The same pattern was observed at 120 DAS where the cut tubers produced the higher number of tubers (20.7) with increased length (8.6 cm) and diameter (6.6 mm). Consequently, these factors resulted in higher yield, 15.7 as compared to 13.6 g bulk^?1 in non-cut treatment.     

Optimizing crop geometry for processing-grade tuber yield,quality and economics of potato in Grey Terrace Soil

Crop geometry has great influence on economically important characteristics such as total yield, processing-grade yield, tuber size distribution and tuber quality in Grey Terrace Soil. An experiment was conducted to develop a suitable crop geometry for the production of higher processing-grade yield and quality of potato tubers. The treatment consisted of three levels of inter-row spacing (60, 67.5 and 75 cm) and four levels of intra-row spacing (20, 25, 30 and 35 cm). Crop geometry significantly influenced growth, yield contributing characters, tuber size distribution and yield of potato. The highest chips, French fry grade tubers and total potato tuber yield were found in 67.5 cm × 25 cm crop geometry without affecting processing quality but all were in the highly acceptable range. Intra-row spacing of 25 cm produced the maximum processing quality tubers, closely followed by 30 cm. The highest gross and net returns with a benefit–cost ratio of 1.75 were recorded in 67.5 cm × 25 cm crop geometry. Therefore, the 67.5 cm × 25 cm crop geometry can be recommended for higher potato tuber yield and processing-grade tubers as well as higher economic return.     

The response of Stevia (Stevia rebaudiana Bertoni) to nitrogen supply under greenhouse condition

Stevia (Stevia rebaudiana Bertoni) is a perennial plant producing some natural sweeteners. Stevia is considered as a new crop in some countries. This study was conducted to find the stevia response to nitrogen fertilizer supply. Different levels of nitrogen (0, 30, 60, 90, 120, and 150 kg/ha from urea source) were used in a greenhouse condition and then the stevia growth and metabolites were assessed under different availability of nitrogen. Results showed that the optimum growth of stevia was obtained by 60 kg/ha nitrogen and more nitrogen supply did not enhance the stevia growth. It was observed that the total steviol glycosides (SVglys) content of Stevia was significantly increased by nitrogen fertilizer application just up to 30 kg/ha, while it decreased by more rates of nitrogen fertilizer. Our result clearly showed that SVglys yield reached to maximum value by application of 60 kg/ha of nitrogen fertilizer. Since the variation of SVglys content and shoot growth of the stevia were compromised by 60 kg/ha nitrogen, it can be concluded that 60 kg/ha of nitrogen fertilizer could be considered as an optimum rate of nitrogen for stevia and could also be recommended for greenhouse conditions.     

Performance of common buckwheat (Fagopyrum esculentum M.) in response to row spacing under ridge and furrow cropping systems in a semiarid region of China

Ridge and furrow systems as well as the wide-narrow row spacing are recognized as good management practices in crop production. To obtain some available information concerning the suitable agricultural practices for buckwheat cultivation in arid and semi-arid area, a two-year field study was conducted to investigate the performance of common buckwheat grown under six cropping patterns: conventional flat single/double row planting (NS/ND); furrow single/double row planting (FS/FD); ridge single/double row planting (RS/RD); single row planting with equal row spacing and double row planting with wide-narrow row spacing practice. Plants grown under the FD system exhibited higher water use efficiency (WUE) and rainfall use efficiency (RUE) than plants cultivated with the NS system, increases with 13.7% and 21.9%, respectively, in 2014, while 9.8% and 14.0%, respectively, in 2015. Plants of the FD system also displayed the greatest leaf area index and canopy openness at growth stage of 40, 60, and 80 days after sowing, maximum biomass production (13.96 t ha^?1) and grain yield (3486.2 kg ha^?1) in 2014, and the least pronounced soil nitrate consumption as compared to plants from other tillage systems. We conclude that FD is the optimum planting pattern for common buckwheat cultivation in semi-arid and arid environments.     

不同株距和缓释氮肥配施量下机插杂交稻的产量及光合特性

【目的】温江地区高产水稻的推荐施氮量为180 kg/hm2,以此为基础,机插稻缓释氮肥与常规尿素适宜配比为7:3基础上,进一步研究密度和缓释氮肥配施量对机插稻分蘖特性、干物质积累量、光合物质生产特性、群体生长率及产量的影响。【方法】采用二因素裂区设计进行了机插杂交稻田间试验。在行距为30 cm下,设3种株距处理为16 cm、18 cm、20 cm;在尿素氮施用量54 kg/hm2下,设4个缓释氮用量为36、66、96和126 kg/hm2,总施氮量相应为90、120、150和180 kg/hm2。在插秧时缓释肥与尿素混合,一次性追施。调查了主要生育期水稻生长和氮素吸收运移量。【结果】缓释氮肥配施量和株距对主要生育期的水稻干物质积累量、光合特性及产量均存在显著或极显著的调控效应,且互作效应显著;缓释氮肥配施量的效应明显高于株距。在机插行距30 cm下,株距为18 cm,总施氮量为150和180 kg/hm2时,可有效提高叶面积指数（LAI）、单茎茎鞘与叶片干物重,叶面积衰减慢,拔节至齐穗期光合势大,群体生长率高,光合特性强,促进干物质累积,在足够穗数的基础上,显著增加了穗粒数,提高了群体颖花量,保持了稳定的结实率和千粒重,从而显著提高机插稻产量。株距为16 cm,施氮量为150 kg/hm2时,水稻群体茎蘖数增长快,拔节后群体茎蘖数缓慢消减,有效穗数足,虽穗粒数显著降低,但有较高的结实率和千粒重,从而协调出较高的产量。而株距为20 cm,配施总氮量为180 kg/hm2处理,在保证有效穗数的基础上,促壮秆和攻大穗,增加了穗粒数,干物质积累量多,灌浆充实量大,千粒重增加。相关性分析表明,株距与缓释氮肥配施量耦合下,尤其以拔节至齐穗期光合势、齐穗期高效LAI与产量相关性较高（r=0.87**~0.91**）,对促进增产更为重要。【结论】在机插行距30 cm下,株距为18 cm,缓释氮肥（96 kg/hm2）与常规尿素（54 kg/hm2）配施总氮量为150 kg/hm2时,能充分发挥本区域机插杂交籼稻高产的优势、提高光合物质生产,产量最高可达11463.8 kg/hm2,为本试验的最佳肥密运筹处理。     

不同密度下增施有机肥对夏玉米物质生产及产量构成的影响

本研究在夏玉米季适当降低种植密度并连续两年施用有机肥,旨在了解黄淮海地区夏玉米群体物质累积和产量构成对有机肥施用量和种植密度的响应,从而降低倒伏风险,确保稳产、高产。试验采用随机区组设计,设高、中、低3个种植密度,分别为90 000株·hm-2、75 000株·hm-2和60 000株·hm-2,3个种植密度下设不同的有机肥施用量处理,其中高密度下设30 m3·hm-2一种施肥量,中密度下设30 m3·hm-2一种施肥量,低密度下设0 m3·hm-2、30 m3·hm-2和45 m3·hm-23种施肥量。研究结果表明:施用有机肥可以有效改善土壤肥力。施用有机肥第1年,在中、低密度下对玉米干物质生产、群体生长速率和产量构成均产生一定的促进作用,但效果不显著。施用有机肥第2年,低密度下玉米群体衰老速率减缓,叶面积指数和棒三叶叶绿素相对含量在生育后期均维持在较高水平,花后群体生长速率维持在较高水平,且与中高密度无显著差异,群体花后生物量增加幅度最大,成熟期地上部总生物量显著提高甚至接近中高密度。低密度下施用有机肥后穗粒数和千粒重均大幅度提高,从而有效补偿了低密度下穗数的不足,最终低密度下施用45 m3·hm-2有机肥处理产量达10 838 kg·hm-2,与中、高密度下施用30 m3·hm-2有机肥处理的产量11 080 kg·hm-2和11 202 kg·hm-2基本持平且差异不显著。由此可见,通过适度降低密度并增施有机肥能够有效合理地调控群体花前花后生长,避免前期旺长和后期早衰,实现保穗保花增重增产的目的。     

移栽秧龄对机插杂交稻产量及群体质量的影响

为探明中、迟熟型杂交稻品种在不同机插秧龄条件下的适应性及品种间生长发育及产量的差异,研究了不同移栽秧龄对机插中、迟熟杂交稻产量及群体质量的影响。结果表明,21 d适龄移栽杂交稻的产量、各生育时期的群体茎蘖数、分蘖成穗率、叶面积指数、抽穗后剑叶光合、群体透光、抽穗期的有效叶面积、高效叶面积、有效叶面积率以及高效叶面积率显著大于迟栽处理。品种选择上,迟熟杂交稻品种无论在产量还是在各群体指标方面均优于中熟品种,尤其是迟熟型中F优498分蘖力中等,株型好,这些特征改善了机插条件下杂交稻群体光合生产和通风透光状况,穗型大且穗粒数较多,茎蘖成穗率较高,秧龄弹性较大,可适当延长秧龄到28 d也能保持较高产量。中熟型中辐优838虽然穗数多,但其穗粒数限制了产量的增加,且其分蘖力过强,导致无效分蘖过多,对机插产量的发挥造成一定影响。研究结果为生产中选择机插适栽秧龄及高产杂交稻品种提供参考。     

New organic substrates and boron fertilizing for production of yellow passion fruit seedlings

The identification of alternative substrates suitable for seedling production is very important, while boron nutrition is also relevant due to plant requirement and its difficult management. Thus, four experiments were carried out from October 2012 to April 2013 to evaluate the effect of substrates using decomposed buriti (Mauritia vinifera Mart.) stem (DBS) and boron fertilizing for seedling production of yellow passion fruit (Passiflora edulis Sims). The experimental design was completely randomized in factorial scheme 6 × 2 + 1, referring to the substrates [S1: DBS, S2: soil and sand 1:1 (20%) + DBS (80%), S3: soil and sand 1:1 (40%) + DBS (60%), S4: soil and sand 1:1 (60%) + DBS (40%), S5: soil and sand 1:1 (80%) + DBS (20%), S6: commercial substrate (additional treatment) and S7: soil, sand and manure 1:1:2] with and without boron. The seedling emergence, emergence rate, plant height, stem diameter, root length, root volume and dry mass of roots and shoots were recorded. The substrates S2 (without B fertilizing) and S4 (B fertilized with 0.5 mg dm^?3) produced seedlings with more than 3.0 g of shoot dry mass and at least 30 cm in height, and can be used for production of high-quality yellow passion fruit seedlings.