Increase In Marketable Yield Research Articles

Weed Control Efficacy, Growth and Yield of Potato (Solanum tuberosum L.) as Affected by Alternative Weed Control Methods

Two field experiments were conducted to assess the response of growth, yield and quality of potato crop as well as weed control efficacy (WCE) to different colours (blue, white and black) of plastic mulches, biodegradable (plastic and rice straw) mulches, infrared transmitting (IRT) plastic mulch and natural herbicides (acetic acid 20% (AA), citric acid (CA) 10% and AA 10% + CA 5%) in comparison with hoeing, metribuzin herbicide and unweeded check. At 90 days after planting, black and biodegradable plastic mulches recorded WCE significantly higher than hoeing treatment with values of 98.1% and 93.8%, respectively, compared with 83.1% for hoeing. High WCE was recorded by AA 20% (90.7%), rice straw (90.4%), white (89.6%), IRT (88.1%) and blue (83.7%) plastic mulches and AA 10% + CA 5% (80.5%) which were similar to hoeing treatment. The lowest WCE (70.2%) was obtained by CA 10% treatment. The highest plant shoot fresh weight was recorded in biodegradable and black plastic treatments. Weed infestation in the unweeded plots reduced marketable yield of potato by 57.8%. All plastic and rice straw treatments produced total and marketable yields similar to hoeing treatment. The increase of marketable yield under synthetic and biodegradable mulches ranged from 118.6 to 155.1%. Application of AA 20% and the mixture of AA 10% + CA 5% achieved tuber yields similar to metribuzin herbicide. Biodegradable plastic recorded the largest tuber volume and the lowest physiological disorder yield. The highest starch content was recorded in black plastic and rice straw mulch treatments. It was concluded that mulches and natural herbicides may provide alternative safe weed management methods to hoeing and/or synthetic herbicides in potato crop, especially for new reclaimed areas and organic farms.

EFFECT OF PRUNNING PATTERN AND SOIL MULCHING ON YIELD AND QUALITY OF KEITT MANGO IN NEW RECLAIMED LANDS

The present study was carried out during 2014 and 2015 seasons on adult Kitt Mango Trees to evaluate 4 levels of pruning pattern (removing one-third, one-half, all branch or without pruning) and 4 types of soil mulching (white plastic, black plastic, rice straw or without soil mulching) on vegetative growth, leaf mineral content ,flowering and yield. Average shoot length, shoot thickness and average number of shoot / tree of Kitt mangos greatly affected with both pruning pattern and soil mulching, especially with removing of one-third of branch and covering soil with white plastic sheet. However leaf N, P and K contents were improved with both one-third and one-half pruning of branches of Kitt mango trees where both white and black plastic of mulch soil were similar in their effect on leaf NPK content. There were an evident increase in fruit set %, total yield (kg/tree) and marketable yield % with one-third and one-half pruning of branch and also with white and black plastic of soil mulching. The increase of marketable yield% due to these treatments could be attributed to the increase of vegetative canopy of leaves which led to prevent sun burn of fruits and to minimize heat solar effect from the soil and protect the fruits in lower parts of the trees. Fruit chemical constituents including TSS%, acidity and L-ascorbic acid slightly affected with different treatments but one-third and one-half prunning of branch as well as with white and black plastic of soil mulch could be recommended as a good horticulture treatments in Kitt mango orchards

Influence of Interspecific Hybrid Rootstocks on Tomato Growth, Nutrient Accumulation, Yield, and Fruit Composition under Greenhouse Conditions

Grafting is considered to be a unique component in sustainable vegetable production. In addition to its usefulness for managing soil-borne diseases, it has been suggested that grafting with vigorous rootstocks can improve crop growth and yield. The objective of this greenhouse study was to assess the effects of different interspecific hybrid tomato rootstocks (Solanum lycopersicum × Solanum habrochaites) on yield, growth, nutrient accumulation, and fruit composition of tomato (S. lycopersicum). Using the determinate tomato cultivar Florida 47 as the scion, plants were grafted onto four interspecific rootstock cultivars including Beaufort, Maxifort, Multifort, and RST-04-105. Overall, the use of rootstocks resulted in total and marketable fruit increase 53% and 66% higher than non-grafted and self-grafted scion plants, respectively. The increase in marketable yield by ‘Beaufort’, ‘Maxifort’, and ‘Multifort’ was largely attributed to an increased number of fruit per plant, whereas higher average fruit weight contributed to the yield increase in plants grafted onto ‘RST-04-105’. Self-grafting of ‘Florida 47’ resulted in similar yield as the non-grafted scion control. Analyses of plant growth parameters demonstrated significant enhancement of total leaf area at first fruit harvest in plants grafted onto interspecific rootstocks as compared with the non-grafted and self-grafted scion controls. In addition to plant growth and yield improvement, enhanced accumulation of nitrogen, potassium, and calcium was also observed in grafted plants. The enhancement in mineral nutrient accumulation was largely related to increased biomass accumulation rather than higher nutrient concentration (on a dry weight basis). The overall accumulation of phosphorus was not influenced markedly by the rootstocks used. In general, grafting with the interspecific rootstocks maintained fruit soluble solids content (SSC) and total titratable acidity (TTA), concentrations of vitamin C, carotenoids, and total phenolics at levels comparable with non-grafted plants, whereas harvest date showed a more pronounced effect on fruit composition.

INFLUENCE OF POTASSIUM LEVELS AND SOME ANTI-SALINITY MATERIALS ON SWEET PEPPER GROWN IN SANDY SOIL AND IRRIGATION WITH HIGH SALINTY WATER UNDER NORTH SINAI CONDITIONS

The present work was carried out during the two successive seasons of 2013 and 2014 at the Agriculture Research Station of Hortic. Dept., Agric. Res. Center, in El- Arish, North Sinai Governorate, Egypt. Sweet Pepper (Capsicum annum L.) Local hybrid Fares was used in this study . The objective of the experiments was to study the effect of four potassium rates i.e., 200 (K1)/fed., 250 (K2)/fed., 300 (K3)/fed., and 350 (K4)Kg/fed. from potassium sulfate 48%) with four treatments of foliar spray by some anti-salinity using (1g/ l-1 Zinc, 5 cm/ l-1 Humic acid, and 0.5g/ l-1 Salicylic acid, and beside the control) under sandy soil which irrigated with high salinity water and saline water irrigation in North Sinai, on the growth, yield and some chemical contents in leaves and fruits of pepper plants as well as fruit quality. Split plot design was used in the experiment. The results showed that all growth parameters, gave the highest values with application of potassium level at the rate of 350 Kg per fed. with foliar spray by any of Humic acid 5 cm/ l-1, Salicylic acid 0.5g/ l-1, and ZN 1g/ l-1 , respectively as well as all fresh and dry weights of pepper plant organs expressed in roots, leaves, and stems, as well as clusters fresh weight and both total fresh and dry weight of pepper plants in the both seasons compared to application of potassium the other levels at (K1, K2 and K3) with any of foliar spray of (Zn, Humic and Salicylic acids). Application of the high potassium level (350 Kg per fed.) with the foliar spray by Humic acid, Zn, and Salicylic acid, showed a significant increase in marketable yield of fruit weight per plant (g), number of fruits per plant, average fruit weight as well as total yield per fed. in addition high potassium level (K4) with the foliar spray with any of salicylic acid, Humic acid and Zn, respectively gave the low contents of Na+ and proline in the leaves and fruits compared to the low levels of potassium in the both seasons. Application of potassium levels K4 or K3 with spraying by Zn, Humic acidand salicylic acid gave the highest values for V.C content and T.S.S in sweet pepper fruits.

Erratum to: Effect of foliar application of fulvic acid on plant growth and fruit quality of tomato (Lycopersicon esculentum L.)

This study was conducted to investigate the effects of foliar application of fulvic acid on plant growth, fruit quality, and yield of tomato. Fulvic acid (20 mL) was sprayed on the leaves of tomato plants at 10, 20 and 30 days after transplant (DAT) at rates of 0 (control), 0.8, 1.1, or 1.6 g·L-1 in water. The 0.8 g·L-1 treatment led to a significant increase in plant height and fresh and dry weight, while the 1.6 g·L-1 treatment led to a significant reduction. The contents of P and Ca were increased, but those of most of the other elements were unchanged in response to the 0.8 and 1.1 g·L-1 treatments. Fruit number and yield of medium- and large-sized fruits were significantly increased in the 0.8 and 1.1 g·L-1 treatments, which subsequently resulted in an increase of marketable yield. The incidence of cracking was generally high in all treatments, except for the 1.6 g·L-1 treatment, which showed a significant reduction in cracking and much smaller fruit size. Blossom-end rot was greatly reduced in all fulvic acid treated plants, and no incidence was observed in the 1.6 g·L-1 treatment. Our study demonstrated that foliar application of fulvic acid at about 0.8 g·L-1 could be used to promote plant growth and increase marketable yield in tomato production.

Rendimento de tubérculos de um clone de batata em função da época de dessecação

A definição da correta época de dessecação, buscando o equilíbrio entre precocidade e rendimento de tubérculos é importante na produção de batata para comercialização in natura. O objetivo com o presente trabalho foi verificar a precocidade de produção e o potencial produtivo do clone de batata CL02-05. O experimento foi realizado no campo experimental da Embrapa Produtos e Mercado, Canoinhas-SC, no cultivo de primavera ("das águas"). Os tratamentos foram compostos por quatro épocas de dessecação (80, 90, 100 e 110 dias após o plantio) aplicadas no clone CL02-05 e na cultivar Agata (controle). O delineamento experimental foi em blocos casualizados com três repetições. A parcela experimental foi composta por quatro fileiras de 10 plantas. Dez dias após as aplicações do dessecante paraquat (Gramoxone, 2,5 L/ha), as plantas das parcelas foram colhidas e os tubérculos avaliados para caracteres componentes do rendimento. Os dados foram submetidos à análise de variância e de regressão polinomial. Verificou-se que a massa de tubérculos comerciais do clone CL02-05 dessecado aos 90 dias após o plantio (DAP) (20,21 t/ha) foi maior que da 'Agata' dessecada na mesma época (17,84 t/ha) e similar à 'Agata' dessecada aos 100 DAP (20,57 t/ha). Nas dessecações de 100 e 110 DAP a massa comercial do clone CL02-05 (28,32 e 41,25 t/ha) também foi significativamente maior que da 'Agata' (20,57 e 21,61 t/ha). Os resultados sugerem que, comparada à 'Agata' que tem massa de tubérculos comerciais otimizada próximo aos 100 DAP, o clone CL02-05 atinge nível similar já aos 90 DAP, oferecendo maior precocidade de produção. O retardamento da dessecação, no entanto, possibilita incrementos significativos na produção comercial até, pelo menos, os 110 DAP, confirmando o alto potencial produtivo do clone CL02-05.

Impact of Bio- and Organic Fertilizers on Potato Yield, Quality and Tuber Weight Loss After Harvest

This study was conducted to assess whether organic fertilization alone or with bio-fertilization could replace mineral fertilization in potato production with no adverse effect on quantity or quality. Therefore, two field experiments were conducted at Maba Farm, Cairo—Alexandria Desert Road in Egypt to evaluate the impact of mineral, organic, and bio-fertilizers on a sandy soil on yield, quality, and weight loss after harvest of potato tubers. Control plots were treated with recommended rates of mineral fertilizer + 11.9 t ha−1 compost and the other treatments were 23.8 t ha−1 compost, 23.8 t ha−1 compost + bio-fertilizer, 11.9 t ha−1 compost + bio-fertilizer, 50% of mineral fertilizers + 23.8 t ha−1 compost, 50% of mineral fertilizers + 23.8 t ha−1 compost + bio-fertilizer, 50% of mineral fertilizers + 11.9 t ha−1 compost + bio-fertilizer, and 35.7 t ha−1 compost. There were significant increases in the total and marketable yield of potato crops from plots treated with 50% of the recommended mineral fertilizers plus 23.8 t ha−1 compost with or without bio-fertilizer as well as from plots that received compost at the rate of 35.7 t ha−1, compared with plots treated with full dose of mineral fertilizer plus 11.9 t ha−1 compost (control). Compost at 23.8 t ha−1 + bio-fertilizer resulted in a significant increase in marketable yield. Nevertheless, total yield obtained from plots treated with compost at 23.8 t ha−1 alone or plus bio-fertilizer did not differ significantly from the conventional control treatment. Compared with conventional fertilizer treatment, plots receiving compost at 23.8 t ha−1 alone or at 11.9 t ha−1 plus 50% mineral fertilizers and bio-fertilizer showed a lower nitrate content in potato tubers. Bio-fertilizer + organic fertilizer at a rate of 11.9 t ha−1 reduced marketable yield by 11.8% and total yield by 9.2%, compared with using organic fertilizer at a rate of 23.8 t ha−1 compost. So, for export of organic potato, which is characterized by 2–3-fold higher product prices, bio-fertilizer in the present study could not be an alternative to organic fertilizer. The highest nitrate content of tubers was obtained in control plots and plots that received 35.7 t ha−1 compost. Conventional fertilizer showed significantly higher weight loss of potato tubers during cold storage than all other treatments. Tuber K content was low in organic potato, whereas no effect was recorded on tuber N, P, or starch content. Hence, these results suggest that organic production of potato (at the level of 23.8 t ha−1 compost) could be an alternative to conventional production without significant reduction in yield, and with low nitrate content and better storability.

Effect of nitrogen fertilization and microbial preparations on potato yielding

The effect of nitrogen fertilization and microbial preparations on yielding and development of potato tuber yield components were assessed in field experiments conducted under soil conditions of Luvic Chernozem. The factors of the experiment were nitrogen fertilization levels: 0, 60, 120 and 180 kg N/ha and the following preparations: BactoFil B10, effective microorganisms and UG<sub>max</sub> soil fertilizer. Nitrogen fertilization caused a significant increase in marketable yield of potato tubers. Yield increments on individual fertilizer treatments ranged from 66% to 140%. An evident effect of this factor was also visible regarding the yield components values. Increase in the number of main stems per 1 m<sup>2</sup> under the influence of growing nitrogen doses occurred from the fertilization level 120 kg N/ha, whereas the number of tubers per 1 stem increased only to the level of 60 kg N/ha. Each nitrogen dose applied within the range to 180 kg N/ha caused a marked increase in an average tuber weight. Conducted investigations demonstrated an unfavourable effect of microbial preparations on the marketable crop yield of tubers and formation of yield components. On the objects where microbial preparations were applied, the marketable yield was lower by 1.5 to 2.3 t/ha than in the control. Analysis of linear regression revealed occurrence of significant dependencies between the total tuber yield and the values of individual yield components. The relationships were the most visible for an average tuber weight formation as evidenced by the value of coefficient of determination (R<sup>2</sup> = 0.983).

마(산약) 생산을 위한 시비법 개선연구

연구내용은 마 재배에 적합한 유기물 및 화학비료 시용량을 검토하였으며, 생육기간 동안 마 생장량, 무기성분 및 allantoin 함량의 변화 등을 조사한 결과이다. 마 재배시 유기물시용 효과 단마의 괴경 수량은 화학비료를 줄여 시용할 경우 감소하였는데, 질소시비량이 높은 관행재배(43-28-32 kg/10a, 퇴비 3톤)에서 2,058 kg/10a의 수량을 보인데 비해 화학비료를 시용하지 않고 10톤의 유기물만 시용한 시험구와 유기물 없이 관행시비량의 반량(22-14-16 kg/10a)을 시비한 시험구는 각각 1,322 kg, 1,404 kg/10a로 수량이 감소하였다. 비료를 배량 증시할 경우 시비량 증가에 따른 수량증수 효과가 나타나지 않았다. 유기물 시용과 경운방법에 따른 생육과 수량 비교 유기물만을 시용하여 단마를 재배할 경우 일반적인 쟁기 경운에서는 10톤/10a 이상을 사용하여야 기준시비량 처리구의 86%의 수량을 확보할 수 있었으며, 트렌쳐심경 재배에서는 유기물 10톤/10a 처리에서 기준시비량 처리구의 95%의 수량을 확보하는 효과가 있었다. 질소와 칼리비료 시비량 개선 시험 질소 시비량에 따른 마 지하부 특성 및 수량은 단마와 장마 모두 질소 32kg/10a에서 최고를 보였으며, 마 밭의 적정 질소시비 수준은 최대수량을 보이는 시비수준의 85%인 27kg/10a로 판단되었다. 칼리 비료의 시비량은 마의 수량에 유의적인 영향을 미치지 않았다. 마의 생장변화와 식물체내 무기성분 변화 마의 지하부 생육은 정식 후 3개월 정도 경과 후 괴경 비대가 급속히 이루어졌으며, 생육기간 중 식물체내에 흡수되는 영양분의 요소별 흡수는 괴경 비대가 시작되는 7월 중순경부터 생체 및 건물 중의 증가와 동시에 증가하는 경향이었다. 생육 기간중 allantoin 함량변화 생육 기간중 allantoin 함량은 지상부생육이 활발한 7~8월경으로 주로 지상부에 많이 포함되어 있으며, 지하부 괴경의 allantoin 함량축적에 따른 마 수확적기는 10월 이후가 적당하며 질소시비량에 따른 allantoin 함량은 큰 차이가 없었다. Yams (Dioscorea spp), which are edible or medicinal tuber crops, are a important crop in South Korea. Yams require a high level of soil fertility. The various cultural practices such as fertilizing and plowing were tested for marketable tuber production in Chinese yam (Dioscorea opposita). Tuber yield was also affected by organic matters in soil. Application higher level of organic matters result in increased each tuber weight and tuber yield per unit area. The nutrient absorption quantity of the plant such as nitrogen, phosphoric acid, calcium and potassium was increased from 100~120 days after planting, which time to begin tuber enlargement. The tuber yield was increased when the fertilization increased in quantity. Total yield and marketable ratio were the highest in 31~32 kg/10a of nitrogen fertilizer. From above result, income become larger with increase of marketable yield and quality improvement at 63% (27 kg/10a) level of conventional N fertilization (43 kg/10a). The tuber yield was not significantly different between with in various application level of potash fertilizer. Tuber size and weight decreased accordingly to decreased fertilizing level, so the rates of small tubers increased greatly at cultivation without chemical fertilizer. In considering the accumulation rates of allantoin in Chinese yam tubers, the apt harvest season was after October. The allantoin quantity of it was not influenced with nitrogen fertilizing. Moreover it was advantageous with decrease of chemical fertilizer and appropriate fertilizing in soil environment protection. Commercial tuber's number and yield were increased in trenching before planting with trencher compared with rotavating with tractor.

The effects of crimson clover companion planting on eggplant crop growth, yield and insect feeding injury

The effect of using crimson clover (CC) (Trifolium incarnatum L.) as a companion plant on crop growth, marketable yield and insect feeding injury was examined using Eggplant, Solanum melongena L. as the neighbouring cash crop. There were two subplot treatments, which included applications of organic insecticides and no insecticides. Planting eggplant directly into CC did not improve most eggplant growth variables and resulted in a yield reduction during year 1. During year 2, when the CC was strip-tilled prior to transplanting the eggplant, several eggplant growth variables were more strongly enhanced in CC than bare-ground (BG) habitats. Eggplant in CC plots suffered less damage by insect folivores but yields were similar among treatments. There were no benefits of using organic insecticides with respect to increased marketable yields in CC treatment plots, but there was an increase in marketable yield in sprayed compared with unsprayed BG subplots. If properly managed, CC may help protect eggplant from insect feeding injury; however, this may not cause an increase in marketable yield.

EFFECT OF WATER STRESS, CALCIUM ION AND TWO NATURAL EXTRACTS LIQUORICES, SOLUAMINE AND METHODS OF APPLICATION ON SOME VEGETATIVE GROWTH CHARACTERS OF POTATO CV. LATONA

This study was carried out at vegetables field of Horticulture and landscape department. College of Agriculture and Forestry. Mosul University. Iraq.. during spring season of 2011, to investigate the effect of three factors: water stress. calcium ion and two natural extracts Licorice. Soluamine in addition to three methods of application in some yield characters of potato (Solanum tuberosum L . cv .Latona) . The experiment includes 24 treatment ( 2 × 3 × 4 ) conducted in a Factorial Experiment within Split – plot system in a R.C.B.D Design. each treatment was replicated three times. The results could be summarized as follows: 1-Exposuing potato plants to water stress during the period of tubers formation and development caused a significant decrease in all yield characters traits. 2- Application of calcium. Licorice and soluamine extracts. significantly increased all yield characters as compared with control treatment. except the mean of tuber weight. 3- Application of calcium and two natural extracts (Licorice and soluamine) by to the soil caused a significant increase in tubers weight. plant yield and total yield as compared to (foliar application). while the tow others methods of application (adding to soil) and (foliar spray + adding to the soil) resulted in a significant increase in marketable yield as comparing with first method (foliar spray) 4- The interaction treatments among calcium. Licorice. soluamine extracts. and methods of application over drawn on reduction the damage effect of water stress in all study characters of the droughted plants.

Using Cajanus Cajan in Biomass Transfer Technology to Increase Yield of Tomato (<em>Lycopersicon Esculentum Mill.</em>)

The experiment was conducted at the Tono Irrigation Project site in the Upper East Region of Ghana. The objective was to investigate the effect of Cajanus cajan mulch and fertilizer application on the growth and yield of tomato (Lycopersiconesculentum). The split plot design, with treatments randomised within each block was used. Fertilizer was applied at three levels (0 kg N/ha, 75 kg N/ha and 150 kg N/ha) as main plot treatments and Cajanus cajan mulch at two levels (0 tons/ha and 15 tons/ha) as sub plot treatments. Mulch, fertilizer and mulch/fertilizer interaction had a significant effect on the growth (height and leaf area) of tomato. Tomato growth was highest at the highest rate of mulch and fertilizer interaction (15 tons/ha and 150 kg N/ha). Highest yield (9.35 tons/ha) was obtained at the highest rate of mulch/fertilizer interaction (15 tons/ha and 150 kg N/ha) and lowest yield (2.8 tons/ha) at control (No mulch and No fertilizer). However, fruit size was highest at half rate of fertilizer and mulch interaction (75 kg N/ha and 15 tons/ha). This accounted for the increase in marketable yield for the treatment. Half rate of fertilizer and mulch (75 kg N/ha and 15 tons/ha) gave the highest profit. Therefore, the use of Cajanus cajan mulch would reduce the dependence on inorganic fertilizers and ensure a sustained improvement in tomato yield.

Effect of intercropping carrot (Daucus carota L.) with french marigold (Tagetes patula nana L.) and pot marigold (Calendula officinalis L.) on the occurrence of some pests and quality of carrot yield

Intercropping combines different aspects of the interaction between organisms in ecosystems and may be classified as a pro-ecological method of plant cultivation limiting the harmful human interference in the environment, especially the use of chemicals. It also allows high yield, good quality, and economic productivity to be achieved. The aim of the present study, conducted in the years 2003–2004 in Mydlniki near Kraków, was to determine the effect of intercropping carrot Nardin F<sup>1</sup> with French marigold (<em>Tagetes patula nana </em>L.) 'Kolombina' and pot marigold (<em>Calendula officinalis </em>L.) 'Promyk' on carrot yield, its quality, and the occurrence of pests. On average in both years of the study, intercropping did not reduce total or marketable carrot yield. In 2003 intercropping contributed to a significant increase in marketable yield compared with yield from sole cropping. In 2004 the dry matter content was higher in the roots of carrots grown with pot marigold. The treatments intercropped with both French and pot marigold were characterized by an increased content of sugars in carrot roots and in 2004 year – of carotenoids. Intercropping had a significant effect on the number of roots damaged by the carrot rust fly, <em>Psila rosae</em>, (the best in this respect was the combination with <em>Tagetes</em>) and by nematodes (the best in this respect was the combination with <em>Calendula</em>). The number of larvae of carrot psyllid, <em>Trioza viridula</em>, was significantly lower in the plots where carrot was intercropped. The study did not find intercropping to have a positive effect on reducing the occurrence of the root aphid.

Effect of Phosphorus Fertilizer Rate on Irrigated Russet Burbank Potato

Phosphorus (P) fertilizer is routinely applied to potato (Solanum tuberosum L.) in Manitoba, Canada; however, little information is available regarding P responses in this region. Field studies were conducted from 2003 through 2006 to determine the impact of P rate [0, 15, 29, 43 kg P ha−1 as broadcast incorporated monoammonium phosphate (MAP)] on Russet Burbank potato. Increasing P rate resulted in a linear increase in marketable yield in 2005, a quadratic increase in 2006, and no effect in 2003 and 2004. Phosphorus application had no effect on the yield of tubers <85 g, tuber number, or quality, but petiole P concentration and postharvest soil-test P levels increased with increasing P rate. Results of this and other studies show that P fertilization may improve potato yields, although increases are not completely predictable. Additional research is required to refine soil-test guidelines and petiole P sufficiency levels for this region.

Effect of differentiated nitrogen fertilisation on the yield and quality of leaf lettuce

Abstract Two field experiments with leaf lettuce were conducted in 2006-2008. The first factor tested was the diversified contents of mineral nitrogen in the soil, amounting to 50, 100 and 150 mg N dm-3 before lettuce cultivation. The second factor tested four nitrogen fertilisers differing in chemical composition and in nitrogen form introduced into the soil: ammonium nitrate 34% N - (NH4NO3), calcium nitrate 15.5% N - (Ca(NO3)2 × H2O + NH4NO3), ammonium sulfate 20.0% N - ((NH4)2SO4), and ENTEC 26% N - (NH4NO3 + (NH4)2SO4 + 0.8% DNPP). Two cultivars of leaf lettuce were used: green leaf ‘Casabella’ (Lollo Bionda type) and red leaf ‘Klausia’ (Lollo Rosa type). The best source of nitrogen for ‘Casabella’ cultivar lettuce was ENTEC 26 fertiliser and calcium nitrate, which resulted in significantly higher yields as compared to ammonium sulfate, yet did not differ from the yields comprising plants fertilised with ammonium nitrate. In the case of the ‘Klausia’ cultivar, ENTEC 26 fertiliser and ammonium nitrate generated the best production results. Regardless the type of nitrogen fertiliser used, the increase in concentration of this element in soil from 50 mg N dm-3 to 150 mg N dm-3 resulted in a considerable increase in marketable yield of both cultivars with simultaneously higher nitrate accumulation and decreased dry matter in the ‘Klausia’ cultivar. Lettuce fertilised with ammonium sulfate as well as with ENTEC 26 presented significantly lower average nitrate content in leaves before harvesting than after application of ammonium and calcium nitrate as a source of nitrogen for the plants. Introduction of ammonium nitrate and calcium nitrate in the dose of 150 mg N dm-3 contributed to nitrate accumulation in the amounts exceeding permissible by legal regulations regarding the content of this element in lettuce, while application of ENTEC 26 allowed us to obtain a high yield size of both lettuce cultivars without risk of exceeding permissible nitrate content.

PRE-PLANT VERSUS IN-SEASON APPLICATION OF PHOSPHORUS FERTILIZER FOR RUSSET BURBANK POTATO GROWN IN CALCAREOUS SOIL

Potato (Solanum tuberosum L.) has active surface roots that may enable phosphorus (P) fertigation. Fertilizer trials were conducted in 2002–2004 with 0 or 224 kg P2O5 ha−1 applied as incorporated pre-plant broadcast, in-season fertigation, or split application (half pre-plant and half in-season). All of the P fertilization treatments increased petiole P concentration over the untreated control in all three years of the trial, but only the pre-plant application resulted in significant increases in US No. 1 and Total yields. Both the pre-plant and the split application resulted in significant increases in Marketable yield (US No. 1 & 2). These results show that P fertilizer should be applied and incorporated prior to planting. Fertigated P does enter into the plant, but the relative efficiency of this method of application for P is poor with regard to important yield and quality parameters and application as such should be limited to “rescue” situations.

STRAWBERRY PRODUCTION WITH PROTECTED CULTURE IN SOUTHERN CALIFORNIA

Total and marketable yield, fruit size and fruit rot were evaluated for 'Camarosa' and 'Ventana' strawberry cultivars grown with or without protected culture in southern California in 2003 and 2004. In both years, bare-root transplants were established on October 5 using standard production methods. Fifty-five days after transplanting, metal posts and arcs were positioned over portions of the field and covered with 0.0324 m-thick clear polyethylene tarp to create structures 4.9 m wide, 25 m long, and 3.5 m high. Each tunnel covered three contiguous strawberry beds, and experimental design was a randomized complete block with four replications, with individual plots consisting of 20 plants. In 2003, early season (January-April 1) marketable yields in tunnels were 90% and 84% greater than outdoor culture for Ventana and Camarosa, respectively. In 2004, use of tunnels resulted in a 140% marketable yield increase for Ventana and 62% for Camarosa (January-March 31), however unusually high temperatures (38°C) in April resulted in reduced yields in tunnels thereafter. In both years, increased early production coincided with highest fresh market fruit prices, resulting in $ 14,000-18,500 ha -1 greater returns compared to open field production. For both cultivars, tunnel production resulted in 45-76% fewer non-marketable fruit due to less rain damage, better fruit shape, and decreased incidence of Botrytis cinerea. For all treatments, fruit size decreased as season progressed and this effect was more pronounced in tunnels after April. Overall, these studies indicate that tunnels have considerable potential for enhancing early-season production and profitability of strawberries in southern California.

The Influence of Selected Agronomic Practices on the Yield and Chemical Composition of Winter Garlic

The Influence of Selected Agronomic Practices on the Yield and Chemical Composition of Winter Garlic The studies were carried out in 2002-2005 on evaluation of covers application (a perforated film with 100 holes·m-2 and polypropylene non-woven) as well as the influence of different plant density (250, 125, 83 and 63 plants·m-2) on the yield and chemical composition of winter garlic cv. Arkus for bunch-harvest. Covering the plants with perforated film and polypropylene non-woven increased the marketable yield by 30.7% in comparison to open field cultivation. Moreover, the covers had a favourable effect on the weight and leaf length as well as on plant weight and bulb diameter. The plants grown under covers showed significantly higher dry weight content in bulbs, total sugars in leaves, but simultaneously less amount of L-ascorbic acid. The increase of plant density from 63 to 250 per m2 caused a significant increase of marketable yield. However, the plants grown at the highest density had the lowest weight and their edible parts had the least amount of total sugar and L-ascorbic acid.

Management of white rot ( Sclerotium cepivorum) of garlic using fungicides in Ethiopia

Four field experiments were conducted at the Debre Zeit and Bakelo areas of North Shewa, Ethiopia in 2003/2004 and 2004/2005 to determine the effects of five fungicides on epidemics of white rot ( Sclerotium cepivorum), and to identify effective fungicides for its management. Five fungicides: tebuconazole as a clove treatment and supplemented basal spray, benomyl, mancozeb, captan and thiram as a clove treatment were applied to Tseday (G-493) and local garlic cultivars. The treatments were arranged in a randomized complete block design with three replications. There was an untreated control for each cultivar. The trials were conducted in fields naturally infested with S. cepivorum. Treatment of garlic cloves with tebuconazole at the rate of 2.1 ml kg −1and spray at 0.25 l ha −1 at stem bases resulted in a significant reduction in initial and final white rot incidence, progress rate, and severity on bulbs. Captan at the rate of 4.17 g kg −1and benomyl at 5.2 g kg −1gave a significant reduction in final disease incidence and the disease was reduced by 16% and 24%, respectively, over the control at Bakelo. At Debre Zeit these fungicides decreased final disease incidence by 40–44%. The highest increase in marketable yield was obtained from garlic treated with tebuconazole (43–73%), captan (48–77%) and benomyl (42–64%) more than the control. Thiram reduced the disease initially, but subsequently did not prove effective. Garlic yield of both cultivars were improved by fungicide application. On average marketable yield increased 27–44.1% at Debre Zeit and 33–70% at Bakelo over the untreated control plots. Differences existed between seasons and locations and these could be due to differences in environment and inoculum levels.

EFFECTS OF NITROGEN RATES ON SUMMER SQUASH GROWTH AND YIELD

Nitrogen (N) is the most growth-limiting for vegetable production in sandy soils. In Florida, current recommendations for preplanting N applications (100 lb/acre of N) in `Crookneck' summer squash (Cucurbita pepo) differ from those used by the growers (&gt;200 lb/acre). Therefore, two field studies were conducted in Ruskin and Balm, Fla., to examine the effect of 50, 100, 150, 200, 250, and 300 lb/acre of N on summer squash growth and yield. Variables collected during this study were plant vigor (0–10 scale, where 0 = dead plant) at 3 and 7 weeks after planting (WAP), petiole sap nitrate-nitrogen (NO3-N) at 4 and 8 WAS, and marketable yield starting on 4 WAS (13 and 10 harvests in Ruskin and Balm, respectively). In Ruskin, plant vigor increased linearly with N rates, whereas there was no significant N effect in Balm. No differences in petiole sap NO3-N were observed in either location. In Ruskin, there was a rapid marketable yield increase (§25%) between 50 and 100 lb/acre of N, followed by no change afterwards. In contrast, there was no yield response in Balm. In the latter location, no crop had been established in the previous 3 years, enabling the soil to maximize its organic N accumulation (&gt;40 lb/acre organic-N), whereas in Ruskin the experimental location had been continuously planted during the last three seasons (§25 lb/acre organic-N). The data demonstrated that organic N is an important source of the nutrient to complement preplant applications in summer squash.