The influence of planting date,sucker selection and density on yield and crop-timing of bananas (cultivar ‘Williams’) in the Eastern Transvaal

In the subtropical banana-growing areas of South Africa, there is a pronounced and consistent tendency for fruit to be oversupplied in the spring (September–November) and undersupplied in the autumn (March–May). Under identical soil, planting material and general management conditions, a crop-timing trial with ‘Williams’ banana was established at Burgershall Research Station, Eastern Transvaal, to compare the effects of planting date (September, December, March), time of first sucker selection (5 and 10 months after planting) and density (1666 and 1250 plants ha⁻¹) on yield and harvest season over 3 crop cycles.Cumulating the yield/ha/annum for the plant crop and first ratoon cycles, there was a small but significant decrease (4%) as planting date was delayed from September to December, and a larger significant reduction in yield (18%) with delay from December to March planting. While cumulative yield/ha/annum for plant crop plus first ratoon increased significantly (19%) at the higher density of 1666 plants ha⁻¹, no differences occurred as a result of sucker selection treatment.March-planted bananas were harvested during the undesirable spring period, and this effect was largely carried over into the first ratoon and second ratoon cycles. December planting was optimal and September planting intermediate from a crop-timing viewpoint. Cumulating all 3 crop cycles, 50% of the total bunch harvest could be timed during the autumn from December planting at a density of 1666 plants ha⁻¹. From September planting, the proportion of autumn-harvested fruit could also be increased by delaying the selection of the first ratoon sucker until at least 10 months after planting. Results demonstrated the in-field potential for overcoming the natural banana shortage in South Africa during autumn.     

Screening of genotypes of menthol mint Mentha arvensis for high yields of herbage and essential oil under late cropping conditions of the sub-tropical Indo-Gangetic plains

Summary

The essential oil yields and expression of related characters were compared for seven cultivar genotypes of menthol mint Mentha arvensis using two methods of planting in the winter rabi – summer season (October to July) in a sub-tropical agroclimatic environment. The crops of all the cultivars were planted in the field by (1) sowing of suckers on 2 January and (2) transplanting germinated pieces of sucker at different times between 17 March to 14 April. Staggering of transplanting time up to 7 April did not affect oil yields and the related plant growth properties of mint crops. The oil yields of the crops planted on 14 April were lower by about 30%. In the early sucker planted crops, the oil yields were about 30% higher than those obtained from the transplanted crops of 17 March to 7 April and about double that obtained from crops transplanted on 14 April. The oil yields from the crops of the superior genotype Kosi were equal to or higher than the corresponding means of all genotypes under both planting methods. The oil yield from the crops of Kosi genotype obtained by sucker sowing method was estimated as 333 kg ha^–1. The corresponding average yield from the crops of this genotype obtained by transplanting of germinated suckers between 17 March and 7 April was about 293 kg ha^–1 and that from the crop transplanted on 14 April was 218 kg ha^–1. With the Kosi genotype, the latter two types of transplanted mint crops gave oil yields lower only by about 12% and 33% compared with the long-duration sucker-sown crop. It is concluded that a crop of mustard (brassica), Bengalgram (chickpea) or wheat sown between October and November and harvested between early March to middle of April could be taken before cropping of the Kosi genotype of M. arvensis by plantlet transplanting. These results demonstrate the potential of the following rotation of crops in the sub-tropical environments: from June/July/August to October/November (kharif cropping season), rice, maize, sorghum or pigeonpea; from November/December to February/March, mustard and Bengalgram or from November/December to April (rabi cropping season), wheat; from March/April to June/July (zaid cropping season), transplanted menthol mint.     

Yield formation in Brussels sprouts

Summary

The effects of three planting dates and three plant densities, covering most of the planting dates and densities used in the Netherlands, on yield determining factors of Brussels sprouts (Brassica olerácea var. gemmifera), were studied in field experiments during three seasons. Planting dates were between the end of April and early July. Plant density ranged between 2.7 and 4.4 plants per m². Planting late in the season initially resulted in more leaves being formed, a higher Leaf Area Index and a longer stem. During crop growth this trend was reversed to a lower number of leaves formed, and in two of the three years a lower LAI and stem length when planting was delayed. The effect of plant density on these characteristics was generally either less pronounced than that of planting date or was absent. There was no, or only limited, interaction between the effects of planting date and plant density on these characteristics. The initial rate of dry-matter accumulation after planting was higher after planting late in the season, but the final amount of standing dry matter was reduced by the late planting. Plant density did not influence the final amount of standing dry matter. There was no interaction between the effects of planting date and plant density on dry-matter accumulation. Planting date and plant density hardly influenced the radiation use efficiency. Overall radiation use efficiency was 2.2 g MJ^–1. The time of bud initiation expressed as numbers of days after planting was advanced by delayed planting, but was not influenced by plant density. Planting late in the season decreased the number of buds per plant and in one of the three years also reduced the weight per bud. A decrease in the number of buds per plant due to increased plant density was more than compensated for by the increase in number of plants per hectare. The final number of buds as a percentage of the final number of leaves, was either not, or not consistently, influenced by treatment. Bud dry-matter concentration at final harvest decreased when planting was delayed, but was not influenced by plant density. There was no interaction between the effects of planting date and plant density on bud dry-matter concentration. The dry-matter harvest index of 30–45% was not greatly affected by treatments. To aim for high yields, planting should be as early as field conditions allow.     

短季亏缺灌溉条件下高密栽培对番茄产量和品质的影响

为充分利用北京地区3—5月的优质光热条件、稳定基质栽培番茄品质,通过改变传统栽培方法,采用在同一设施内,人为控制植株高度,只留2穗果和水分亏缺灌溉等栽培措施,研究不同栽培密度(每667 m2分别栽4000、6000、8000株)对番茄产量及品质的影响,结果表明:每667 m2栽6000株处理的果实可溶性固形物含量达到8...     

Effects of density,rectangularity and row orientation on apple trees,measured in a multiv ariated experimental design

A single-plant-plot design was found very suitable for a study of growth and yield effect of tree density, rectangularity and row orientation on a wide range of intra and inter-row planting-distances.Densities from about 250 to 40 000 trees per hectare were studied in 2 apple cultivars on 2 weak-growing rootstocks over a period of 8 years. On unpruned trees a maximum yield of 80 tons per hectare of ‘James Grieve’ and about 95 tons of ‘Spartan’ was recorded. At the highest densities these yields were reached 2–3 years after planting.As early as the second to third year the growth was restricted at densities over about 1000 trees per hectare. A higher yield per tree at medium densities than at lower densities for the first fruiting-years is supposed to be an effect of growth resulting in earlier fruiting.A high rate of rectangularity reduced the yield only on densities of 1200–1550 trees per hectare. The lack of a significant effect on lower and higher densities is discussed.The growth and yield of rows oriented North—South were 17% higher than of those oriented East—West.     

紫豇豆“绵紫豇1号”播种期及密度试验

摘要：为研究紫豇豆品种绵紫豇1号的配套栽培技术,为其栽培及推广提供科学依据,进行了6个播种期及3个种植密度的双因子试验,分析不同播种期与密度对绵紫豇1号的生育期、植物学性状和产量的影响。结果表明：对绵紫豇1号豇豆产量的影响顺序依次为播种期＞播种期与密度互作＞密度;产量随播种期的推迟呈下降的趋势,随密度的增大呈先升后降趋势。综合得出,绵紫豇1号在四川地区的适宜播种期为3月25日前后,播种期不宜太迟,太迟会影响产量;在土壤中上等肥力水平下的适宜种植密度为667 m2栽8 100株。     

Relationships between canopy size,light interception and productivity in conventional avocado planting systems

Avocado (Persea americana Mill.) is a relatively under-developed tree crop, grown commercially in climates ranging from tropical to temperate. Orchard productivity across a broad range of tree crops has been demonstrated to be related to total light interception. However, little information is currently available for avocado. Here we document the relationships between canopy volume per hectare, total orchard light interception and yield per ha for avocados of cultivar ‘Hass’ grown in low density planting systems. Total orchard light interception increased with canopy volume, with increases in light interception per unit canopy volume becoming smaller at the higher levels of canopy volume/ha. Yield/ha increased with light interception and canopy volume up to approximately 80–84% total light interception and 30,000–35,000 m³ canopy volume/ha. It is unclear whether the trend in yield/ ha at the very highest measured levels of orchard light interception and canopy volume should be described as plateauing or declining. Mean fruit weight decreased as light interception increased, although the relationship varied between seasons. For these conventional planting systems there is no yield benefit from increasing canopy light interception above 80–84%, and there may be yield decline at higher levels of orchard light interception.     

Effect of planting density on the number and weight of tulip daughter bulbs

The effects of planting densities on the development and yield of tulip bulbs were studied for the cultivar ‘Lustige Witwe’ (planting size 8–9 cm, type A) in two successive growing seasons. The total number of lifted bulbs decreased with increasing density due to shrivelling of certain buds. The shrivelling started at the time of anthesis, mainly in the buds in the axils of the outermost bulb scales.At densities between 5 × 5 and 12 × 12 cm plant^?1 the relative growth rate (R_w) decreased with increasing density. A difference in the R_w values between the two seasons was probably partly caused by differences in the stocks used for the experiments. The highest weight increase was found at a density of 214 bulbs m^?2 in 1969 and 229 bulbs m^?2 in 1970.     

不同种植密度对套种草莓与樱桃番茄产量及效益的影响

通过草莓套种樱桃番茄密度试验,对草莓和樱桃番茄抗病能力、产值、产量进行研究分析。试验结果显示,667 m2草莓套种1 200株樱桃番茄、在3月中旬套种,樱桃番茄和草莓无明显共生病虫害,产量、效益等最佳。     

瓠瓜杂交一代不同种植密度对制种产量的影响

以越蒲1号瓠瓜亲本为材料,进行了母本不同种植密度制种比较试验。试验结果表明,母本株距30 cm 和40 cm 处理的雌花始花、授粉、种瓜采收等生育期基本一致;30 cm 处理制种量比40 cm 处理的少,平均减产2.4%,差异未达显著水平;单瓜种子质量和数量差异较大,30 cm 处理的单瓜种子质量比40 cm 处理平均减小约27.0%,单瓜种子数量下降26.7%;种子百粒质量、发芽率和水分含量相近。因此,瓠瓜制种母本株距以40 cm 为宜。     

The influence of tree training and plant density on growth,yield components and yield of Arabica coffee cv. Ruiru 11

Assessment of tree growth and yield components of Coffea arabica L. cv. Ruiru 11, as influenced by tree training on single or two-stem systems at densities between 1600-4800 trees per ha during the first production cycle was carried out at Ruiru, Kenya over three years. Trees trained on the two-stem system tended to be taller than those on singlestems. Although the results were not clear, trees at low plant densities had thicker stems irrespective of the training system. The total number of primary branches was significantly higher on trees trained on the two-stem system. However, bearing primaries and productive wood were higher on the single-stem system during the first year of production. The number of bearing primaries and productive wood increased in subsequent production years on the two-stem system. Training trees on the two-stem system significantly depressed yields in the first production year by 245 to 842%, irrespective of plant density. Yields of clean coffee increased significantly with tree density irrespective of the tree training method. Yields over the production period increased by 33, 45,27 and 9% with increases in planting densities from 1600 to 2400, 2400 to 3200, 3200 to 4000 and 4000 to 4800 trees per ha, respectively. However, yields increased at a decreasing rate at densities above 3200 trees per ha. The proportions of the large grade ‘A’ sized coffee beans were not significantly affected by the treatments. It was concluded that it is possible to raise two stems during the first production cycle of ‘Ruiru 11’, although this might not be economical. Single stems would be preferred and a high plant density of between 3200-4000 trees per ha would be optimum during the first coffee production cycle.     

The Effects of Plant Density and The Pattern of Plant Arrangement on The Yield of Parsnips

The results of two spacing experiments, one with var. Offenham only and the other with vars. Offenham and Avonresister, are described and discussed.

The number of plants per sq. ft. affected mean root size; about 2 plants per sq. ft. gave the highest yield of roots >2 in. crown diameter, whereas about 4 to 6 plants per sq. ft. gave the highest yield of prepackingsized roots (1½ in. to 2½ in.). At a given plant density, however, varying the row spacing over a range likely to be used commercially had no significant effect on the total yield of roots or their size grading.

The greatest difference in the yielding ability of the two varieties occurred at low plant densities, where Offenham outyielded Avonresister by up to 88%, whereas at high plant densities the yield difference was only about 10%. A mathematical model relating yield to plant density was used to analyse the results and characterize the difference in the response of the two varieties to plant density.     

马铃薯行株距比对光合特性及产量品质的影响

为了研究马铃薯在相同种植密度下高产优质最佳的行株距,采用37 500和60 000株 ? hm-2两种密度,通过扩大行距缩小株距,分别设置4个和7个行株距比处理,研究其对马铃薯茎叶干物质积累、光分布、光合特性、叶绿素荧光特性、产量及块茎淀粉、蛋白质、维生素C、还原糖含量的影响。结果表明：行株距比在低密度下为1.5、高密度下为2.5时,可提高茎叶干物质量、叶面积指数、叶绿素含量、净光合速率（Pn）、蒸腾速率（Tr）、气孔导度（Gs）、最大光能转化效率（Fv/Fm）、实际光化学量子效率（PSⅡ）、光化学猝灭系数（qP）、鲜薯产量及其淀粉、维生素C、可溶性蛋白含量,而胞间CO2浓度（Ci）、非光化学猝灭系数（NPQ）和还原糖含量的变化规律与之相反。‘青薯9号’高产优质的行距/株距在37 500和60 000株 ? hm-2种植密度下,分别为63.3 cm /42.2 cm和64.6 cm /25.8 cm。     

高山栽培密度对晓丰甘蓝产量及效益的影响

比较了高山栽培5种不同种植密度对晓丰甘蓝的生物学性状、产量及经济效益的影响.试验结果表明,高山栽培晓丰甘蓝株行距为40 cm×45 cm时,其产量、纯收入较其他种植密度分别提高2.3％～14.2％和6.3％～19.3％,是一种较为合适的高山种植密度.     

Morphology,yield and quality of ashwagandha (Withania somnifera L. Dunal) roots and its cultivation economics as influenced by tillage depth and plant population density

Summary

Ashwagandha (Withania somnifera L. Dunal; Solanaceae) is being cultivated around the world mainly for its root which has rejuvenative properties. Field experiments during 1999–2001 under semi-arid tropical conditions of Hyderabad, India studied the effect of tillage depths (15 and 30 cm) and plant population densities (20, 40, 60 and 80 plants m^–2) on root morphology, yield and quality and cultivation economics of ashwagandha. Preparatory tillage to 30 cm depth in combination with a density of 60 plants m^–2 gave the highest root yield of 1.2 t ha^–1 which was 50% higher than that following 15 cm tillage depth and the same density. This is attributed to the favourable effect of the former treatment leading to 33, 37 and 21% increases in plant height, number of branches per plant and shoot biomass yield, respectively. Further, this treatment produced most (68%) best quality root pieces. Main root length, length of lateral roots and diameter of lateral roots were significantly increased, while the diameter of main root and the number of laterals decreased. Furthermore, increase in plant density from 20–80 plants m^–2 increased production of best quality roots from 42% to 59% under shallow tillage and from 53% to 71% of root yield under deep tillage. The implications of change in root morphology are discussed in the light of production of different grades of roots, their market preferences and economics. Deep tillage was equally advantageous for seed production, but plant population density for maximum seed yield (211 kg ha^–1) was lower at 40 than at 60 plants m^–2 for maximum root yield. Maximum gross and net returns and benefit-cost ratio occurred following the highest root yield.     

Ethephon as a fruit thinning agent for ‘Murcott’ mandarins

Ethephon (2-chloroethylphosphonic acid) was tested as a fruit thinning agent in an experiment on the mandarin cultivar ‘Murcott’.Ethephon was effective at 150 and 300 mg l^?1, but 300 mg l^?1 gave the higher yield and larger fruit sizes over a 2-year period, following a single spray application during natural fruit fall in November. The thinning percentage was also higher when ethephon was applied to trees with a heavy crop density than when applied to trees with a light crop density.     

Performance of ‘Discovery’ apple on M.9, M.26 and MM.106 rootstocks at two densities

Summary

The apple rootstocks M.9, M.26, and MM.106 were evaluated for their efficiency in bringing ‘Discovery’ apple trees into production. The experiment, carried out over a ten- year period compared two planting densities at 1666 and 3333 trees per ha. Tree vigour differences between rootstocks were measured in term of trunk growth, tree volume, weight of branches pruned off and final weight of the above-ground parts of the trees. Fruit production is presented both as total yield and as the weight of first class fruit. Fruit colour development is also shown. Cropping efficiency is calculated and presented in relation to the different vigour measurements. The results confirm that ‘Discovery’ is slow to come into production. M.9 was the most productive rootstock, but due to vigour differences MM.106 gave the same yields per tree, although the latter had the lower yield efficiency. M.26 performed poorly; its vigour was similar to M.9 but it produced the lowest yields.     

Effects of biennial cropping and controlled shoot density on yield performance and fruit quality in red raspberry (Rubus idaeus L.)

Effects of annual versus biennial cropping with varying shoot densities on plant structure, berry yield and quality were studied in ‘Glen Ample’ raspberry over a period of four seasons (two cropping years). In the vegetative phase, primocane height and internode length were larger in the annual than in the biennial cropping system. These parameters as well as Botrytis infestation increased with increasing shoot density. In both cropping years, berry yields per unit area were about 20% higher in the biennial cropping system, whereas yields per shoot were not significantly different in the two systems. In both cropping systems, yields per shoot strongly declined with increasing shoot density, while yields per metre row increased slightly. Regardless of cropping system, yields per metre row did not increase with increasing shoot density beyond eight shoots per metre. The concentrations of dry matter, soluble solids, titratable acidity and ascorbic acid as well as the intensity of juice colour all declined with increasing shoot density. We conclude that under controlled shoot density conditions, there is little scope for biennial yield increases that fully compensates for the lost crops every second year. However, the system greatly facilitates berry harvest and eases plant disease pressure.     

种植密度对秋季甜玉米产量及主要农艺性状的影响

为了研究秋季不同种植密度对甜玉米产量及主要农艺性状的影响,以甜玉米"HZ388"为试验材料,设置每667 m~2种植3 200、3 600、4 000、4 400、4 800、5 200株6个密度处理,进行观察比较。试验结果表明:667 m~2种植4 000株时,空秆率为零,商品率、穗粗和穗粒数达到最大,分别为90.0%、4.68 cm和532.7粒;在一定范围内,667 m~2无苞叶商品鲜穗产量较大,为650.2 kg。建议在武汉及周边地区秋季甜玉米"HZ388"的适宜种植密度为667 m~2种植4 000株。     

种植模式及密度对不同籽用西葫芦品种病害及产量的影响

选取3个籽用西葫芦品种,分别采用平作和垄作2种种植模式和3个密度处理,研究了不同密度和种植模式对不同籽用西葫芦品种病害发生和产量的影响。结果表明:不同密度处理和种植模式对籽用西葫芦病害的发生有显著影响,在低密度垄作条件下,白粉病发病较轻,绵腐病不发生,高密度平作条件下,病害相对较重;同一品种不同种植模式下,垄作种植较平作种植产量显著增加;同一品种同一种植模式下不同密度处理中,低密度和对照较高密度处理产量高。目前,平作种植条件下,高密度种植不适宜河套灌区的籽用西葫芦生产,若要提高种植密度需要改变种植模式。