In-row Plant Spacing Research Articles

Effect of in-row spacing on weed suppression and yield of ‘Covington’ and ‘Monaco’ sweetpotato

Abstract Organic sweetpotato growers have limited effective weed management options, and most rely on in-season between-row cultivation and hand weeding, which are time consuming, are costly, and deteriorate soil quality. Studies were conducted at the Samuel G. Meigs Horticulture Research Farm, Lafayette, IN, and at the Southwest Purdue Agricultural Center, Vincennes, IN, in 2022 and 2023 to determine the effects of in-row plant spacing and cultivar selection on weed suppression and organic sweetpotato yield. The experiment was a split-split plot design, with in-row spacings of 20, 30, and 40 cm as the main plot factor, weeding frequency (critical weed-free period and weed-free) as the subplot factor, and sweetpotato cultivar (‘Covington’ and ‘Monaco’) as the sub-subplot factor. However, in 2022, we evaluated only in-row spacing and weeding frequency because of the poor establishment of ‘Monaco’. In 2023, sweetpotato canopy at 5 wk after transplanting (WAP) decreased as in-row spacing increased from 20 to 40 cm, and sweetpotato canopy cover of ‘Monaco’ (62%) was greater than that of ‘Covington’ (44%). In-row spacing did not affect weed density at 4, 5, and 6 WAP. As in-row spacing increased from 20 to 40 cm, total sweetpotato yield pooled across both locations in 2023 decreased from 30,223 to 21,209 kg ha−1 for ‘Covington’ and from 24,370 to 20,848 kg ha−1 for ‘Monaco’; however, jumbo yield increased for both cultivars. Findings from this study suggest that an in-row spacing of 20 cm may provide greater yield than the standard spacing of 30 cm for both ‘Monaco’ and ‘Covington’.

Spatial–Temporal Analysis to Investigate the Influence of in-Row Plant Spacing on the Sugarcane Yield

Spatial–Temporal Analysis to Investigate the Influence of in-Row Plant Spacing on the Sugarcane Yield

The effects of deficit irrigation on water use efficiency, yield and quality of drip-irrigated tomatoes grown under field conditions in Zimbabwe

Water availability in the root zone directly affects the yield and quality of tomatoes yet in most cases in sub-Saharan Africa water is either expensive or scarce. It is therefore important to establish and utilise suitable irrigation strategies in order to produce the crop in a sustainable way. In this study the effect of conventional and deficit irrigation treatments on yield, fruit quality and water use efficiency (WUE) were determined. Four trials were conducted at the University of Zimbabwe Farm from 2014-2017 with four treatments per trial: T1 = 100%, T2 = 80%, T3 = 60%, and T4 = 50% of crop water requirements (ETc). Treatments had equal number of plants per trial with an in-row plant spacing of 0.3 m and 0.5 m between adjacent rows. ETc was determined daily for each treatment and the corresponding volume applied through one drip emitter per plant. Fruits from each treatment were gathered while ripening and the total yield obtained. WUE was calculated by dividing the total fresh yield by total irrigation water applied. Maximum yield was obtained where 100% ETc was applied, with no significant difference between yield of plants at 80% and 60% ETc, except in 2016. Yield decreased with 50% ETc in 2014, 2015, and 2017 with no significant difference in yield between 60% and 50% ETc treatments in 2016. The 2015 season recorded the highest yield when compared to other trials showing that we can save 40% of water resulting in high WUE with minimum loss in yield. Deficit irrigation reduced fruit water but increased fruit soluble solids (°brix), vitamin C and fruit acid concentrations. Firmness was best when 60% ETc was applied. These results show that deficit irrigation is feasible for crop water management options for the production of high-quality field-grown tomatoes without major yield reductions.

Interaction of genotype-ecological type-plant spacing configuration in sorghum [Sorghum bicolor (L.) Moench] in China.

Grain sorghum has been a significant contributor to global food security since the prehistoric period and may contribute even more to the security of both food and energy in the future. Globally, precise management techniques are crucial for increasing grain sorghum productivity. In China, with diverse ecological types, variety introduction occasionally occurs across ecological zones. However, few information is available on the effect of ecological type on genotype performance and how plant spacing configuration influences grain yield in various ecological zones. Hence, a series of two-year field experiments were conducted in 2020 and 2021 in four ecological zones of China, from the northeast to the southwest. The experiments included six widely adapted sorghum varieties under six plant spacing configurations (two row spacing modes: equidistant row spacing (60cm) mode and wide (80cm)-narrow (40cm) row spacing mode; three in-row plant spacings: 10cm, 15cm, and 20cm). Our results indicated that ecological type, variety, and plant spacing configuration had a significant effect on sorghum yield. Ecological type contributed the highest proportion to the yield variance (49.8%), followed by variety (8.3%), while plant spacing configuration contributed 1.8%. Sorghum growth duration was highly influenced by the ecological type, accounting for 87.2% of its total variance, whereas plant height was mainly affected by genotype, which contributed 81.6% of the total variance. All test varieties, developed in the south or north, can reach maturity within 94-108d, just before fall sowing in central China. Generally, sorghum growth duration becomes longer when a variety is introduced from south to north. A late-maturing variety, developed in the spring sowing and late-maturing regions, possibly could not reach maturity in the early-maturing region. The row spacing modes had no significant affect on sorghum yield, but the equal-row spacing mode consistently caused higher yields with only one exception; this might imply that equal-row spacing mode was more advantageous for boosting sorghum yield potential. In contrast, decreasing in-row plant spacing showed significant positive linear associations with sorghum grain yield in most cases. In addition, these results demonstrated that sorghum is a widely adapted crop and enables success in variety introduction across ecological zones.

GROWTH AND YIELD OF CAULIFLOWER AS AFFECTED BY BORON SPRAY AND IN-ROW PLANT SPACING

A field experiment was tested in the Central Laboratory for Agricultural Climate Experimental Farm, Dokki, Giza Governorate, Egypt, during the two growing seasons of 2019/2020 and 2020/2021 on cauliflower. The aim of this research was to study the effect of plant spacing foliar spraying with different concentrations of application of boron (B) on the vegetative growth, chemical content and curds yield of cauliflower cv. Amshiry under field conditions. Plants were sprayed with 50, 100 and 200 ppm at 20, 40, 60 and 80 days after transplanting, whilst the in-row plant spacing was 0.3 and 0.5 m between plants. Results showed that boron foliar application significantly improved vegetative growth parameters, curds yield and its components and chemical composition of leaves and cauliflower plant. Likewise, using 0.50 m plant spacing significantly enhanced plant fresh weight, plant height, leaves fresh weight and leaves dry weight and chemical composition of leaves and curds. The highest yield per plant was obtained by plant spacing 0.5m combined with 200 ppm boron followed by plant spacing 0.50 m combined with 100 ppm boron. On the other hand, the production from land units increased by using 0.3 m in-row plant spacing while the production of individual plants was less than 0.5m treatment. The 200 ppm boron application gave the highest net profit per feddan followed by 100 ppm. The lowest net profit was obtained by 0.30 m plant spacing combined with control treatment.

Modelling the effect of variation of in-row spacing on kernel m-2 in maize

Maize (Zea mays L.) yield is often reduced when the in-row plant spacing is not uniform. I used a variant of the KNMAIZE model to investigate the mechanisms responsible for the reductions. KNMAIZE determines kernels per plant from the relationship between the proportion of the assimilate supply from photosynthesis that is partitioned to the kernels and the assimilate required to sustain kernel growth. Kernels abort when their assimilate requirement exceeds the supply. Algorithms were developed to create variation of in-row plant spacing (characterized by CV) and emergence percentage. The effect of spatial variation on kernels m−2 depended upon the ability of the dominant plants (higher plant growth rates associated with larger in-row spacing’s) to increase kernels per plant to compensate for the reduction on the dominated plants (lower plant growth rates resulting from smaller in-row spacing’s). When the ability of the dominant plants to respond was zero (kernels ear−1 = florets ear−1, excess capacity = 0), kernels m−2 started decreasing as soon as the CV > 0. When the dominant plants had excess capacity (i.e., kernels per ear < florets per ear), the beginning of the decline occurred at progressively larger CVs depending upon the magnitude of the excess capacity. Populations greater than the minimum needed for maximum yield provide the excess capacity on dominant plants to buffer kernels m−2 and yield against variation of in-row spacing and reductions in emergence.

Planting Geometry Effects on the Growth and Yield of Dryland Cotton

The declining Ogallala Aquifer beneath the Southern High Plains may necessitate dryland crop production and cotton (Gossypium hirsutum L.) is a well-adapted and potentially profitable alternative crop. The limited growing season duration of the Texas Panhandle and southwestern Kansas, however, imposes significant production risk due to incomplete boll maturation. Emphasizing earlier boll production that is usually confined to sites on lower fruiting branches may reduce risk, but offsetting high planting densities are needed to maintain desirable lint yield. Our objectives were to quantify planting: 1) row width and 2) in-row spacing effects on growth, yield, and fiber quality of dryland cotton. Field tests of row widths from 0.25 to 0.76 m and plant densities with in-row spacing ranging from 0.075 to 0.15 m were conducted from 1999 to 2005 on a nearly level Pullman clay loam (fine, mixed, superactive, thermic Torrertic Paleustoll) managed in a wheat (Triticum aestivum L.), cotton, fallow (W-Ctn-F) rotation. To expand the basis of comparison, cotton growth and yields were simulated using GOSSYM and long-term (1958-2000) weather records from Bushland, TX, as input for all combinations of 0.38 or 0.76 m row widths and plant spacing of 0.075, 0.10 and 0.15 m. Experimental and computer simulated plant height and harvested boll number increased significantly with increased row spacing and, occasionally, in-row plant spacing. Modeled lint yield for 0.38 m rows decreased by approximately 50% compared with the 582 kg·ha-1 yield for conventional row spacing, which was practically duplicated by field observations in 2001 and 2004. Measured fiber quality occasionally improved with conventional row spacing over ultra-narrow rows, but was unaffected by plant spacing. Because narrow rows and frequent plant spacing did not improve lint yield or fiber quality of dryland cotton, we do not recommend this strategy to overcome a thermally limited growing season.

Planting date and in-row plant spacing effects on growth and yield of cabbage under plastic mulch

Florida is ranked third in total cabbage production in the U.S. and it is traditionally grown on bare ground with subirrigation. The use of plastic mulch and drip irrigation is widespread for other vegetable crops and can enhance water and fertilizer use efficiency and yield. The objective of the study was to evaluate plant growth, yield and head quality traits of cabbage using three plant populations and four planting dates on a plastic mulch system. Cabbage was transplanted in mid September (SEP), mid October (OCT), early November (NOV), and early December (DEC) in the 2013–14 and 2014–15 growing seasons, spanning the entire planting season for commercial operations in northeast Florida. There was no interaction among planting dates and plant populations for total and marketable yields or biomass. For both seasons, the SEP and OCT plantings showed a faster growth rate than NOV and DEC during the first 70 days after transplanting; however, differences in total biomass accumulation were only seen in 2013–14. Biomass decreased quadratically in 2013–14 with an increase in in-row spacing. Average marketable yield for both years was 62.7, 60.5, 46.2, and 58.6Mgha−1 for SEP, OCT, NOV and DEC, respectively. As plant population decreased, marketable yield increased linearly in 2013–14 while no differences were seen in marketable yield among plant population treatments during 2014–15 season. Plant growth rate and yield were correlated to growing season average air temperature and solar radiation. The SEP, OCT and DEC planting dates benefited from more favorable weather conditions, while low air temperatures and reduced solar radiation had a negative effected on cabbage yield for the NOV planting.

Sweet potato production in a short-season area utilizing black plastic mulch: effects of cultivar, in-row plant spacing, and harvest date on yield parameters

The sweet potato (Ipomoea batatas (L.) Lam.) requires a long, hot growing season to attain good yields. In a cool climate, the use of black plastic mulch to heat the soil can improve growth but cultivars, plant spacing, and harvest date must be carefully selected to optimize yields and to attain market quality standards. In this two-year study in Quebec, Canada, two sweet potato cultivars (‘Georgia Jet’ and ‘Beauregard’) were grown at four in-row spacings (15, 30, 45, and 60 cm) and harvested at three dates (mid September, late September, and early October). Cumulative growing degree-days (GDD) with base temperatures of 10°C and 15.5°C were calculated for each harvest date. ‘Georgia Jet’ had higher total and marketable yields than ‘Beauregard’. In-row spacing had no effect on yields per hectare of ‘Beauregard’ and only affected ‘Georgia Jet’ in one year of the study. Average root weight of sweet potatoes, yields per plant, and number of roots per plant increased with wider spacing. Delaying harvest by one or two weeks had little effect on ‘Beauregard’ but increased yields of ‘Georgia Jet’. GDD may be a useful predictor of optimum harvest date but a lower base temperature used to calculate GDD may be desirable with ‘Georgia Jet’ as its yields continued to increase even when growing under cool conditions of late September and early October.

Optimum Planting Configuration for High Population Plasticulture Grown Cabbage

Florida is a major fresh-market cabbage (Brassica oleracea L. var. capitata) producing state in the United States. The current cabbage production system relies on bare ground and subirrigation that requires a large volume of water to irrigate the crop. The bare ground system facilitates a maximum of 48,438 plant/ha, while there is a potential to increase plant population per area using plasticulture and drip irrigation. The objectives of this study were to determine the optimum cabbage plant population and plant arrangement that maximizes marketable yield per area for a high cabbage population plasticulture system. Cabbage was grown on 1.2-m-wide raised beds with black plastic mulch and drip irrigation. Plants were grown in either three or four rows with in-row plant spacings ranging from 15 to 35 cm and plant populations ranging from 41,518 to 129,167 plants/ha. Cabbage marketable yield increased as in-row spacing increased. Yields ranged from 19.7 to 69.7 Mg·ha−1. Marketable yield was not different between 3 and 4 rows for in-row spacings above 25 cm. The 15 and 20 cm in-row spacing produced significantly lower yields in the 4-row configuration as compared with the 3-row configuration in Fall and Winter 2011. Wider in-row spacings produced a greater percentage of heads of marketable size while reducing the percentage of small heads when compared with narrower in-row spacings. Mean head weight increased as in-row spacing increased and a 3- or 4-row configuration with an in-row spacing between 25 and 30 cm had consistently high yields in all three seasons compared with narrower in-row plant spacings. These results indicated that with a high population plasticulture system variable plant populations could be selected. In-row plant spacings between 30 and 35 cm may be beneficial for early plantings while a 25-cm spacing could be more productive for later plantings, especially when weather conditions are favorable.

MAXIMIZING POTATO PRODUCTION VIA NITROGEN FERTILIZATION AND PLANT SPACING

The potato plants (Solanum tuberosum L.) vs. valor were exposed to different levels of nitrogen fertilizer (60, 100, 140, 180 kg N/feddan (4200 m2)) and in-row plant spacing (12.5, 25 and 50 cm) for maximizing the yield production to match food security needs under climate change impacts on Delta region, Egypt. The experiment was carried out during two growing seasons (2010/2011 and 2011/2012) in split plot design at El-Bossily Farm, Agricultural Research Center, El-Behira Governorate, Egypt. The vegetative growth characteristics and yield parameters were measured. The result of this study verified that increasing nitrogen level up to 180 kg N/feddan significantly increased the vegetative growth, total and marketable yields than the other N treatments. The in-row plant spacing 50 cm was significantly increased vegetative growth and yield (kg/plant), but the total yield (kg/m2) had different trend. The highest total yield /m2 was obtained by 12.5 cm treatment. The interaction effect of 180 kg/feddan of N and 12.5cm in-row plant spacing were increased the total tuber yield (kg/m2) significantly. In contrary, the best marketable yield (tubers > 35 mm) /m2 was obtained by 25 and 50 cm in-row plants. This study was concluded that the best agronomic practices for potato production obtained by application 180 kg N/feddan of with in-row plant spacing 25 cm treatment. The economical consideration of the different treatments showed that the best total net income was obtained by 180 kg/feddan N with 50 cm in-row plant spacing.

Optimizing Sweetpotato Production for Fresh and Processing Markets through Plant Spacing and Planting-harvest Time

Consumption of sweetpotato (Ipomoea batatas) has increased in the past decade in part because of its nutritional and health attributes, and because of the availability and convenience of processed products. The sweetpotato processing industry is expanding and supplying more sweetpotato products than ever before. Unlike the medium-sized roots (U.S. no.1) preferred for fresh market, large (jumbo) roots is accepted and in certain cases desired by the processing industry, and overall yield is preferred over strict sizing requirements and aesthetic appeal. Therefore, this study investigated the yield increase and grade proportions in response to plant spacing and extension of the growing period to improve profitability of the production system. Experiments with ‘Beauregard’ and ‘Evangeline’ sweetpotato were conducted in Mississippi and Louisiana during 2010 and 2011. Treatments consisted of a combination of early and late planting date and delay in harvest, in-row plant spacing, and row width. Yield increase was inconsistent with delaying harvest and appears to depend on environmental conditions at harvest late in the season. Marketable yield was consistently greater in early plantings than late plantings. Yield of U.S. no.1 grade was unaffected by delaying harvest regardless of planting date. Delaying harvest in early plantings contributed to increase jumbo-sized roots and marketable yield. The economic assessment of delaying harvest in early plantings indicated a gain in net benefit either when hand harvested for fresh market or field run bulk harvested for processing. Row width and in-row plant spacing had only a marginal effect on yield of canner grade (small-sized roots). The economic assessment of changing plant density indicated no gain in net benefit, which indicates that choice of plant density can depend on other factors.

Effects of Planting Configuration and In-Row Plant Spacing on Photosynthetically Active Radiation Interception for Three Irrigated Potato Cultivars

Research studies have evaluated the production of potatoes (Solanum tuberosum L.) grown in conventional and bed planting configurations. However, intercepted photosynthetically active radiation (PAR) from these planting configurations has not been quantified. A study conducted in 2008 and 2009 quantified and compared the intercepted PAR from three planting configurations (four row conventional ridged-row [4RC], five row bed [5RB], and seven row bed [7RB]), and from different plant spacings of cvs Russet Burbank, Russet Norkotah, and Ranger Russet potatoes under sprinkler irrigation. A second study was conducted in 2007 to evaluate the relationship between PAR and leaf area of Russet Norkotah and Russet Burbank for the three planting configurations. These studies were conducted at the USDA-ARS Northwest Irrigation & Soils Research Lab in Kimberly, ID, on a Portneuf silt loam (coarse–silty mixed mesic Durixerollic Calciorthid). The canopy of Russet Norkotah and Ranger Russet potatoes grown in 5RB and 7RB planting configurations intercepted more PAR during the early vegetative and tuber initiation growth stages compared to the 4RC planting configuration at equal populations in 2008 and 2009 at all measurement dates. The canopy of Russet Burbank intercepted more PAR during the early growth stage in 2008 when planted in the bed planting configurations compared to the 4RC planting configuration, but not on the July 17, 2008 and July 9, 2009 dates. The canopy cover of Russet Burbank potatoes planted in the 4RC planting configuration tended to catch up with the bed planting configurations quicker than the other two cultivars. In general, the quantity of PAR intercepted as affected by planting configuration did not influence total tuber yield and other measured production variables. Cumulative PAR interception 0–72 days after planting (DAP) was increased 35%, 38%, and 32% for the 5RB and 65%, 69%, 23% for the 7RB relative to the 4RC planting configuration for Ranger Russet, Ranger Norkotah, and Russet Burbank, respectively. Cumulative PAR interception for the season was increased 15%, 16%, and 4% for the 5RB and 23%, 23%, 5% for the 7RB relative to the 4RC planting configuration for Ranger Russet, Ranger Norkotah, and Russet Burbank, respectively. The relationship between intercepted PAR and leaf area for Russet Norkotah during the early vegetative and tuber initiation growth stages was significantly different between the three planting configurations, with intercepted PAR at a given leaf area in the order of 7RB>5RB>4RC. For Russet Burbank, the relationship was significantly different for the 5RB and 7RB compared to 4RC planting configuration only, with intercepted PAR at a given leaf area in the order of 7RB=5RB>4RC.

Growth and Yield Response of Watermelon to in-row Plant Spacings and Mycorrhiza

En los ultimos anos se ha registrado un significativo aumento en las areas cultivadas con sandia (Citrullus lanatus [Thunb.] Matsum. & Nakai) a nivel mundial. La distancia entre plantas en la hilera tiene un efecto significativo en su crecimiento y rendimiento, y puede generar competencia por agua y nutrientes. Se estudiaron los efectos de diferentes distancias en hilera (1,0; 1,5; 2,0 y 2,5 m) y de inoculaciones con micorrizas arbusculares (AM), Glomus mosseae, sobre el crecimiento y el rendimiento de la sandia. El ensayo se llevo a cabo en condiciones de campo durante 2003, 2004, y 2005. En el ano 2003 se observo un aumento cuadratico sobre la longitud del tallo principal, numero de hojas y ramas laterales debido al aumento de la distancia entre plantas de 1,0 a 2,5 m. En 2004, con un aumento de separacion entre plantas se redujo el rendimiento temprano, y el numero de frutos disminuyo en 2003 y 2004. Durante el ensayo, la produccion total y el numero de frutos disminuyeron con el aumento de la separacion entre plantas, mientras en el ano 2003 aumento el peso de los frutos. La inoculacion de micorrizas aumento la longitud del tallo principal y el numero de ramas laterales el 2003. Las plantas micorrizadas presentaron un mayor rendimiento temprano (2005) y numero de frutos (2003 y 2005). La inoculacion aumento la produccion total el 2005, mientras el peso del fruto no fue afectado durante la cosecha temprana o final. En este estudio, el marco de plantacion de 1,0 m mostro la produccion temprana y total mas alta manteniendo un alto peso del fruto. El crecimiento y aumento del rendimiento de la sandia, debido a la micorrizacion no fueron consistentes, por lo tanto, la inoculacion de micorrizas no puede ser recomendada como una practica de produccion estandar.

Evaluation of In-Row Plant Spacing and Planting Configuration for Three Irrigated Potato Cultivars

Research studies have shown that planting potatoes (Solanum tuberosum L.) in a bed configuration can improve water movement into the potato root zone. However, plant spacing recommendations are needed for potatoes planted in a bed configuration. This study was conducted to evaluate the effect of in-row plant spacing and planting configuration on yield of Russet Burbank, Russet Norkotah, and Ranger Russet potatoes under sprinkler irrigation. For the three cultivars, the effect of in-row plant spacing (three spacing treatments) for each planting configuration (4 row conventional ridged-row [4RC], 5 row bed [5RB], and 7 row bed [7RB]), and the effect of planting configuration at a uniform population on total tuber yield, U.S. No. 1 tuber yield, tubers per ha, average size (by weight), and large tuber yield were investigated at the USDA-ARS Northwest Irrigation & Soils Research Lab in Kimberly, ID on a Portneuf silt loam (coarse-silty mixed mesic Durixerollic Calciorthid) in 2008 and 2009. The greatest influence of in-row plant spacing was on average size and tubers per ha. In general, as in-row plant spacing increased (plant population decreased) the average tuber size increased and tubers per ha decreased. There was little influence of in-row spacing on measured production variables under the bed planting configurations except for tubers per ha which generally increased with narrower plant spacing. For Russet Norkotah and Ranger Russet there were few differences in measured production variables between planting configuration treatments. For Russet Burbank, the 4RC planting configuration had 14.6% significantly greater total tuber yield than the 7RB planting configuration, 20.2% greater U.S. No. 1 tuber yield than both bed planting configurations, and 25.2 and 29.9% greater large tuber yield than the 5RB and 7RB planting configurations, in 2009. Optimum production of Russet Norkotah and Ranger Russet potatoes is possible under all the planting configurations and plant spacing range evaluated in this study, granting growers flexibility in their systems, however, evidence from this study suggests that production of Russet Burbank may be less suited to bed planting configurations.

Effects of In-row Spacing on Eggplant Yield

Research was conducted to determine appropriate in-row spacing for eggplant (Solanum melongena) and to determine the best economic returns of this practice. ‘Classic’ eggplant seedlings were transplanted at in-row distances of 1.0, 1.5, 2.0, 2.5, 3.0, and 3.5 ft. Eggplant height decreased linearly as in-row spacing increased. In-row spacing affected total eggplant fruit number, with no fruit number differences among 1.0, 1.5, 2.0, and 2.5 ft, averaging ≈46,800 fruit/acre. Total fruit weight followed a trend similar to that for total fruit number and there were no differences among 1.0, 1.5, 2.0, and 2.5 ft (ranging between 18.2 and 19.9 tons/acre). From an economical standpoint, the comparison between 2.0 and 2.5 ft resulted in the former spacing having a marginal return rate of 8.03% in relation to an in-row spacing of 2.5 ft, which indicated that growers would earn $0.08 extra for each $1.00 of net profit by switching from 2.5 to 2.0 ft in-row plant spacing.

A survey of stand establishment and in-row spacing uniformity in Washington potato fields

Missing plants and non-uniform in-row plant spacing can result in economic loss for potato growers. In-row seedpiece and plant spacing uniformity of 70 Washington potato fields was measured, and factors contributing to missing plants investigated from 2000 through 2002. Ninety-one percent of the fields were planted with cut seedpieces, and the remaining 9% were planted with cut seedpieces, and the remaining 9% were planted with whole, uncut seed tubers. Russet-type cultivars were planted in 79% of the fields, and the remaining 21% were planted with red-skinned and yellow- and white-fleshed cultivars. Seedpiece or plant spacing deviated an average of 25% from the intended spacing mean, with a range of 7% to 43%. Coefficients of variation (CV) for grower in-row plant and seedpiece spacing ranged from 18% to 69% compared with a hand-planted check average of 13%. Based on the growers’ intentions, the average plant population of the 70 fields should have been 44,000 plants ha−1, but averaged only 40,600 plants ha−1. On average, 6% of the grower-intended stand was missing because of planter skips, while less than 1% was missing due to seedpiece failure or decay. There were 1,980 clumped seedpieces ha−1 and each clump typically contained two seedpieces. Twenty-one percent of the fields had at least 700 planter-skips ha−1 where three or more consecutive plants were missing. Despite management efforts, planters were typically unable to place seed uniformly at the intended spacing. Improved planter and seed-cutting-operation management along with new planter technology would likely improve Washington potato stands.

Effect of Multiple Plants per Plug on Processing Tomato Yield in California

In recent years, an estimated 65% of processing tomato acreage has converted from direct seeding to transplanting the crop. Growers have been switching to transplants for a number of reasons, including land use efficiency, water conservation, and weed management. Field studies investigating plant spacing and multiple plants per transplant plug (cell) were initiated when observations by growers indicated that there were seemingly decreased fruit yields from transplanted crops. A transplant density experiment was established in 2004 in a commercial field of processing tomatoes grown on the west side of Fresno County in the San Joaquin Valley, the major tomato production area in California. The field trial investigated in-row spacing (37.5 cm and 75 cm), the number of plants per transplant plug (1, 2, or 3), on a medium vine size variety (Halley 3155) and a large vine size variety (AB2). Individual plots were large enough for mechanical harvest. Yield results indicate that these two varieties responded similarly to increasing plant density. In general, a spacing of 37.5 cm with 2 or 3 plants per plug yielded significantly more than 1 plant per plug, regardless of variety. There was no yield advantage in seeding 3 plants per plug when compared to yields with 2 plants per plug, regardless of variety or in-row plant spacing. A plant spacing of 75 cm with only 1 plant per plug yielded the least.

(370) In-row Plant Spacing Affects Early Season Fruit Yield of Strawberry Grown in a Winter, Annual Hill Production System

On standard two-row black polyethylene covered beds, `Camarosa', `Rosa Linda', and `Sweet Charlie' strawberry plants were grown at 23, 31, 38, or 46 cm within-row spacing during the 1997–98 and 1998–99 seasons at Dover, Fla. Ripe fruit were harvested twice weekly from December through March. The first 8 weeks of harvest was considered the early period; the late period consisted of all harvests after the first 8 weeks. The effect of spacing on early marketable yield was consistent across seasons and cultivars. The 23-cm spacing resulted in the highest marketable yield per unit area, followed by the 31-, 38-, and 46-cm spacing. The percentage of fruit that were small (unmarketable) was higher at the 23-cm spacing than at the wider spacings (40% vs. 35% or 36%), but spacing did not affect the percentage of fruit that were misshapen. For the late harvest period, a spacing effect on marketable yield occurred in 1998–99, but not in 1997–98. The 23-, 31-, and 38-cm spacings in 1998–99 resulted in similar late period yields, which were 15% to 21% higher than the yield resulting from the 46-cm spacing. These results indicate that marketable yields per plant during the late period were higher at the wider spacings.

Growth and Yield of Watermelon on Polyethylene Mulch with Different Spacings and Nitrogen Rates

Suggested watermelon planting densities and N rates vary on a large scale, indicating that there is insufficient knowledge about their effects. Therefore, the objective of this study was to evaluate the effects of N rate and planting density on growth, yield and quality of watermelon [Citrullus lanatus (Thunb.) Matsum &amp; Nakai] grown on black polyethylene mulch. The field experiments with `Crimson Sweet' watermelon were conducted in two climatologically different growing regions. The treatments were factorial combinations of three in-row plant spacings (0.5, 1.0, and 1.5 m) and three N rates (115, 195, and 275 kg·ha-1). Part of the N (35 kg·ha-1) was applied preplant and the remainder was fertigated. Vine length increased linearly up to 7 weeks after planting (WAP) as N rate increased from 115 to 275 kg·ha-1, and up to 9 WAP as plant spacing increased from 0.5 to 1.5 m. Total and marketable yields per ha or per plant did not increase with N rates above 115 kg·ha-1. Average fruit weight and fruit size distribution were generally unaffected by N rate. Leaf N concentration increased as N rate increased, although leaf N concentrations at the lowest N rate (115 kg·ha-1) even at 9 WAP were relatively high (43.3 to 47.3 g·kg-1). Total and marketable yields per ha were linearly decreased with an increase in plant spacing from 0.5 to 1.5 m, and the same was noticed with the total and marketable number of fruit per ha. With increased plant spacing average fruit weight increased and fruit size distribution shifted to larger categories.