The Effects of Adding Soluble Salts to the Casing Layer on The Yield and Size of Cultivated Mushrooms

The yield results of six field experiments with bulb onions are presented and it is concluded that : (1) The total yield of ripe bulbs increased with increasing number of plants per sq. ft. until an optimum was reached and thereafter the yield declined.

(2) At the optimum plant densities for total yield the bulbs were too small for normal market purposes but were of a suitable size for pickling whole.

(3) Some varieties of onion would not produce large bulbs even when grown at low plant densities; thus the choice of varieties for ware bulb production is of paramount importance.

(4) The fitting of a mathematic model to the density/yield data showed that if varieties were ranked for yield at anyone plant density this ranking would remain the same at all other plant densities. Absolute yield differences between varieties were, however, greatest at low plant densities.

(5) Decreasing the distance between rows at a given plant density increased the total yield of bulbs. At 7 plants per sq. ft., a density suitable for commercial dry bulb production, reducing the row spacing from 18 in. to 9-12 in. increased yield by 10 to 30%.

     

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.     

Chemical Composition of Cortland Apple Leaves in Relation to Nutritional Treatment

Five experiments carried out over three years are described in which the effects of irrigation at various growth stages on the yield of peas from plants grown at different plant densities were determined. Results showed that, irrespective of the density at which the plants were grown, plants irrigated at the start of flowering and again as the pods were swelling produced significantly higher yields than unirrigated plants. Yield of peas per plant was consistently reduced as density increased but yield per unit area did not show a consistent relationship with plant density from year to year. The results indicated that, even when irrigation is available, plant densities of five to six plants per sq. ft. should not be exceeded.     

Influence of planting geometry on growth,yield and quality of rainfed garlic (Allium sativum L.) cultivated under Mediterranean conditions

Summary

The establishment of the optimum plant population has been shown to be one of the most crucial determinants of the marketable yield of bulbous crops. This study was conducted to determine the best plant arrangements for maximum yields and maximum bulb quality in rainfed garlic (Allium sativum L.) grown under Mediterranean conditions. The effects of row width and plant spacing on the yield and quality of the two cvs. Morado de Pedroneras and Germidour, were investigated on Córdoba, Spain, in Vertisol Chromoxerert soil. In 1987–1988, a wet growing season, higher yields and higher bulb quality were obtained than in 1988–1989; cv. Germidour yielded more per unit of land area of higher quality bulbs during both seasons. Narrow row width and/or narrow plant spacing resulted in higher values of dry matter, LAI, LAD, CGR and yield, whereas wide row spacing and/or wide plant spacing resulted in higher ware-sized bulb yield. LAD was closely related to yield (r² = 0.96**) and total dry matter (r² = 0.90**). Mean leaf surface was affected by plant density and climatic conditions and showed a high positive relationship (r² = 0.90**) with the percentage of Extra grade of bulbs (>50 mm). As a result of this study, a row width of 45–60 cm with plant spacing of 12–16 cm is recommended for cv. Germidour and 45 × 16 cm for cv. Morado, to maximize the proportion of high-quality yield under Mediterranean rainfed cropping systems.     

Plant density studies with banana (cv. Williams) in a subtropical climate. III. The influence of spatial arrangement

Summary

At the standard recommended density of 1666 plants ha^?1, the influence of rectangular (3 m rows×2 m in the row), hedgerow (4×1.5 m) and tramline (6 m rows alternating with 2 m rows × 1.5 m) plant spacings was investigated on the growth and productivity of ‘Williams’ banana over five cropping cycles. There were no significant differences in pseudostem or leaf morphology, leaf emergence rate or crop cycle duration between spacings. There were also no bunch mass differences between spacings in the P and R1 cycles, whereas in the R2, R3 and R4 cycles, tramline bunches were respectively 7.6, 7.0 and 9.0% smaller than those from rectangular-spaced plants (P<0.05 in the R4). Overall productivity (yield per annum) was similarly reduced by 7.4% from rectangular to tramline plantings, although this was not significant. Productivity of the hedgerow plantings was intermediate at 4.6% less than the rectangular.     

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.     

The relation between method of propagation,plant density and growth,mineral uptake and yield of dasheen (Colocasia antiquorum, Schott.)

Two field experiments were carried out to investigate the effect of method of propagation (including two proposed new methods) and plant density on the growth, mineral uptake and yield of dasheen (Colocasia antiquorum, Schott.).Planting different pieces of “seed” resulted in a higher percentage germination, higher percentage efficiency of solar energy conversion and better growth characters of the plant, in the order: cormel, apical, half-apical, corm piece and quarter-apical piece, respectively.Increasing the plant density decreased the growth characters of the plant and increased the percentage efficiency of solar energy conversion.The nitrogen, phosphorus and potassium concentrations were not affected by types of dasheen seeds, whereas the absolute amount per plant followed the same pattern of change as the dry matter content.Distance between plants had no statistically significant effect on the concentrations of nitrogen, phosphorus and potassium in the plant tissues. However, the absolute amounts of these minerals per plant decreased as the plant population was increased.Planting with the cormel resulted in the highest total yield. However, the difference in total yield between planting with the apical and half-apical pieces was not statistically significant. A similar situation was found when planting with quarter-apical and corm pieces. Therefore, it is recommended that the apical piece is cut into two equal halves in order to use a given amount of apicals to reduce the corm pieces when planting.Increasing the plant population, by reducing the distance between plants from 45 to 30 cm, resulted in an increased yield per hectare. However, reducing the distance between plants to 15 cm resulted in a decrease in yield.     

Plant density studies with direct seeded tomatoes in Ontario, Canada

In direct seeded tomato density experiments with constant rectangularity of 1.0 carried out at Preston and Simcoe Research Stations, Ontario, Canada in 1971, the effect of increasing plant density from 4.2 to 62.1 plants/m² was to increase total plant weight, total fruit weight and ripe fruit weight per unit area. The proportion of ripe fruit to total fruit increased with increased density, and ripe fruit yields from a single harvest of up to 14 kg/m² were obtained.Using the reciprocal yield-density equation (when W is the mean weight per plant (or plant part) at density , A and B are constants, and density is the only variable) to analyse the experiments, showed that both the A and B constants were influenced by cultivar while the A constant was influenced more by fertilizer application than was the B constant. In general the effect of increased fertilizer was to increase the yield potential ( ) for total plant weight and total fruit weight, but this effect was not so marked for ripe fruit weight.     

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.     

Plant density studies with banana (cv. Williams) in a subtropical climate. I. Vegetative morphology,phenology and plantation microclimate

Summary

The influence of plantation age and plant density on pseudostem size, canopy cover and vegetative growth characteristics of banana cv. Williams was investigated over four cropping cycles at Burgershall Research Station, in the subtropical Eastern Transvaal. Densities were 1000, 1250, 1666 and 2222 plants ha^?1. Over all densities, pseudostem height, lamina area, numbers of functional leaves at flowering and LAI increased with plantation age up to the second ratoon (R2). This increase in canopy cover caused vegetative and total cycle intervals to be extended progressively from plant crop to R3. Within cycles, higher density had little effect on plant height or lamina length, but induced thinner plants with significantly narrower leaves than at low density. Peak ratoon LAI at flowering almost doubled between 1000 and 2222 plants ha^?1. At 1000 plants ha^?1, four cropping cycles were completed in the same period as three cycles at 2222 plants ha^?1. Annual leaf emergence rate was significantly reduced by up to five leaves with an increase in plant density from 1000 to 2222 plants ha^?1, which was also accompanied by a 3–4°C reduction in pseudostem temperature. Up to six more leaves per plant were produced at 2222 plants ha^?1 and only 14% of the available radiation was transmitted through the primary canopy compared with 30% at 1000 plants ha^?1. Crop cycle interval is an important component of annual yield at different densities.     

Strawberry fruit yield and quality responses to flower bud removal: A simulation of damage by strawberry blossom weevil (Anthonomus rubi)

Summary

The effect of flower bud severing (with scissors) on the yield and fruit quality of strawberry (cv. Elsanta) grown on raised, polythene-mulched beds varied with plant size and numbers of flower buds per plant. On very small plants (with an average of seven flower buds and yielding 105 g of fruit per plant) severing reduced yield in direct proportion to the proportion of flower buds severed, irrespective of whether severing included or did not include removal of the primary (first node) flower bud. There was no evidence of crop compensation. On larger plants (with 24, 70 and 117 flower buds and yielding 0.34 kg, 0.73 kg and 1.16 kg of fruit per plant respectively) severing up to 12 buds per plant did not significantly affect yield: mean berry weight increased by up to 11% and the percentage fruit (by number) in quality class I increased from 67% to 72% in response to severing. Two mechanisms of yield compensation were, apparent i) an increase in mean berry weight, and ii) the maturing of alternative replacement flower buds. Severing slightly delayed by 1–2 d the date by when 10% and 25% of fruit was picked. Implications for the economic damage threshold for flower bud severing by the strawberry blossom weevil are discussed.     

陇东旱塬地区不同栽培模式对马铃薯产量和经济效益的影响

为探索陇东旱塬地区马铃薯不同栽培模式的产量和经济效益,采用单因子随机区组试验设计,以马铃薯品种陇薯7号为材料,共设4种栽培模式。处理T1为露地坑栽,处理T2为黑色地膜单行栽培,处理T3为黑色地膜双行栽培,处理T4为黑色地膜双行微沟栽培,通过农艺性状、商品率、产量和经济效益的比较,选择出最佳的栽培模式。结果表明：相较于露地坑栽模式,3种地膜覆盖栽培方式的出苗率略低、生育期晚,而株高、分枝数、地上干质量、穴薯块数、穴薯质量均较高,其中地膜覆盖双行微沟栽培方式（T4）表现最佳, 667 m2产量最高,为3 280.2 kg,较露地坑栽增产19.5%;且667 m2产值最高,达到3 936.28元;667 m2纯收益较露地坑栽增收657.2元,增加率达27.6%;因此,地膜双行微沟栽培不但产量高,而且纯效益也高,可作为陇东旱塬地区马铃薯栽培方式进行推广应用。     

The consequences of cultural practices on growth and cropping of peach trees subjected to localized irrigation: Effects of soil management,nitrogen fertilization and tree density

SUMMARY

Cultural practices were studied in peach tree orchards irrigated with microsprinklers, herbicide strips being maintained along the tree rows. Differences in fruit cropping between treatments varied in the same way as tree vigour, the most vigorous trees having the highest production capacities. Concerning soil management, ground cover vegetation (permanent or temporary) improved fruit production compared with soil cultivation. According to leaf analysis, ground cover vegetation appeared to ameliorate the conditions of trees nutrition. This effect was probably mainly due to increasing soil resistance to compaction; applying organic matter was not effective in improving the performance of trees grown with soil cultivation compared with those grown with ground cover vegetation. Increasing fruit tree density also contributed to increased fruit production. Nevertheless, more than 600 trees per hectare did not allow further increase in fruit yield for the experimental cultivar. Lastly, nitrogen fertilization seemed particularly important for improving the fruiting of peach trees.     

薤(藠头)生长动态与分蘖观察

为探究薤生长发育与分蘖规律,以江西地方品种生米藠头为试材开展了薤生长动态及其分蘖的观察研究。结果表明:薤植株鲜质量、根鲜质量、鳞茎鲜质量和叶鲜质量及株高、叶数、根数、最大叶长等均随生长进程逐步增加,呈单峰曲线的增长动态,且均在鳞茎膨大期增长最快。薤分蘖发生于鳞茎膨大期,一般行3～4级分蘖,分蘖数(X)与分蘖级数(n)的关系为:X=2n。薤鳞茎鲜质量与单株叶数、叶鲜质量和分蘖数呈显著正相关,与单株根数、根鲜质量和植株鲜质量呈极显著正相关。     

Effect of cold temperature durations of onion sets in store on the incidence of bolting,bulbing and seed yield

The experiment was conducted at the experimental area of the School of Plant Sciences, University of Reading during 1996. The planting material comprised of sets (graded to 22.5 mm diameter) of two cultivars, Hygro and Delta. The sets were stored at 5 °C for nine chilling durations, between 10 and 90 days. A control treatment (sets stored at room temperature of 20 °C for days) was also included in the experiment for comparison. Sets of both cultivars treated for 90 days at 5 °C, produced nearly seven times more bolters than those treated for 20 days. Cool temperature treatment for 10 days was too short to induce bolting. Number of florets and percentage of seed bearing florets per umbel increased with lengthening cold durations and this resulted in higher seed yield per umbel. Mean bulb weight per plant was found to increase with shortening the period of low temperature treatment. For bulb crop, storage of sets at 20 °C for 90 days appears to be optimum, as it checked bolting and increased average bulb weight and bulb yields m⁻² in both cultivars.     

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.     

Postharvest sprouting of onion bulbs grown in different temperature and C02 environments in the UK

Summary

The effects of different mean growing season temperatures and C0₂ concentrations during bulb production on postharvest bulb sprouting in a common storage environment at Reading, UK, was examined in two cultivars of the Rijnsburger type of onion (Allium cepa L.). Crops were grown in the field in temperature gradient tunnels maintained at either 374 or 532 ppm C0₂. At crop maturity, cohorts of bulbs were harvested, transferred to a constant temperature room (at an average of 11.6°C) and the subsequent duration to sprouting recorded. The duration to the onset of sprouting (expressed as days in storage until the first bulb sprouted) was not affected by cultivar, mean growing season temperature or CO₂ concentration, and was 165 d. The subsequent rate of sprouting (expressed as bulbs per day) was a positive linear function of mean growing season temperature, but no effects of CO₂ or cultivar were detected. Mean rate of sprouting increased from an average of 0.036 bulbs per day at 12.3°C to 0.093 bulbs per day at 18.6°C. Rapid sprouting in storage was associated with lower levels of total non-structural carbohydrate in the bulbs at the time of harvest. Thus, postharvest susceptibility of onion bulbs to sprouting in storage is expected to increase in warmer crop production temperatures.     

The Minimization of Variability in Experiments on Apples Planted on the Site of A Previous Orchard: I. The Effect of Cultural Treatments Associated with Three Years’ Arable Cropping

Most of the frequency distributions of onion bulb weight throughout the growing period were found to be significantly and positively skewed. The positive skewness was significantly greater at high density than at low and increased significantly with time from sowing. A nomogram relating yield of various onion grade sizes to plant density was derived. For a particular cultivar grown in a known environment such a nomogram enables the plant density for optimum yield of a specified grade to be predicted.     

不同扦插方式及栽培密度对紫薯“内17-71”产量的影响

为探究不同栽培方式对紫薯“内17-71”产量的影响，探索其最佳扦插方式及栽培密度，比较研究了不同扦插方式(正插3、5、7节和倒插3、5、7节)及不同株距(17、20、25、33、50 cm)对“内17-71”藤叶和薯块产量的影响。结果表明：无论正插或倒插处理，藤叶667m²产量均随扦插节位的增多而增加，其中正插5节、正插7节处理较高，分别为1 840.03、2 539.05 kg；且其薯块667 m²产量显著高于其他处理，分别为1 840.92、1 987.66 kg。随着栽培密度的提高，藤叶和薯块667 m²产量均表现出先增加后降低的趋势，而大中薯率则呈现下降趋势，其中株距25、20、17cm处理的薯块667m²产量分别为1 967.65、2 164.97、2 045.47 kg，显著高于其余处理。综合考虑种植成本及市场对大中薯的需求变化等因素，紫薯“内17-71”的栽培方式以株距20～25 cm、行距100 cm，正插5～7节为宜。     

The growth and yield of virus-tested and visually healthy commercial Narcissus stocks from different localities

Summary

Virus-tested stocks of Narcissus pseudonarcissus cv. Carlton were compared in the field with commercial stocks which were at least 97% free from plants with visually obvious virus symptoms. Despite planting bulbs of similar weight and apparently uniform anatomical structure the number of growing points in the comparative stocks sometimes differed depending on the locality in which the bulbs were produced. Consequently, leaf number in year one, which is related to the number of growing points was used to adjust flower and bulb yield. After adjustment where necessary, the mean bulb yield of virus-tested stocks was 9-20% greater than that of commercial stocks. Increased bulb yield of virus-tested compared with visually healthy commercial stocks resulted from greater mean bulb weight. Virus infection apparently had no effect on bulb number. Virus-tested stocks flowered three to four days earlier than the commercial stocks but no clear differences in flower quality or number were detected.