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1.
The effect of seedpiece spacing on the efficiency of nitrogen (N) use by the potato crop is generally unknown. The objective of this experiment was to determine the effect of seedpiece spacing on tuber yield, yield components and N use efficiency parameters of two potato cultivars. Potato cultivars Atlantic and Shepody were grown at two rates of N fertilization (0 or 100 kg N ha?1) and three seedpiece spacings (20, 30, or 40 cm) in 2000 to 2002. Wider seedpiece spacing increased mean tuber weight and the number of tubers per stem, but decreased total tuber yield. The higher tuber yield at the narrow seedpiece spacing was attributed to higher biomass production in combination with lower tuber specific gravity. Seedpiece spacing had no consistent effect on plant N accumulation, and therefore no consistent effect on N uptake efficiency (plant N accumulation /N supply from the soil plus fertilizer). However, a small increase in soil NO3-N concentration in the hill at topkill at wider seedpiece spacing suggested plant N accumulation was slightly reduced at wider seedpiece spacing, but at a level that could not be detected from a plant-based measure of N accumulation. The reduced dry matter accumulation, but similar plant N accumulation, resulted in lower N use efficiency (plant dry matter accumulation / N supply) at wider seedpiece spacing. Wider seedpiece spacing also resulted in generally lower values of N utilization efficiency (plant dry matter accumulation / plant N accumulation) for the 40-cm compared with the 20- and 30-cm seedpiece spacings. Effects of seedpiece spacing on N use efficiency parameters were generally consistent across cultivars and fertilizer N rates. Wider seedpiece spacing did reduce the efficiency of N use by the potato crop; however, the magnitude of the effect was small under the conditions of this study.  相似文献   

2.
Plant root architecture offers the potential for increasing soil water accessibility, particularly under water-limited conditions. The objectives of this study were to evaluate the root architecture in two genotypes of sorghum (Sorghum bicolor (L.) Moench) differing in root angles and to assess the influence of different deficit irrigation regimes on root architecture. The response of two sorghum genotypes, ‘Early Hegari-Sart’ (EH; steep root angle) and ‘Bk7’ (shallow root angle) to four irrigation treatments was investigated in two replicated outdoor studies using large pots. The results indicated that EH possessed steeper brace and crown root angles, fewer brace roots, greater root biomass, and root length density than Bk7 at deeper soil depths (i.e., 15–30 and 30–45 cm) compared with a shallower depth (i.e., 0–15 cm). Across the soil profile, EH had greater root length density and length of roots of small diameter (<1 mm) than Bk7. Accordingly, EH showed more rapid soil-water capture than Bk7. Different levels of irrigation input greatly affected root architecture. Severe deficit irrigation (25% of full crop transpiration throughout the season) increased the angle and number of crown roots, root biomass, and root length density compared with 75 and 100% of full crop transpiration treatments. Consequently, root system architecture can be effectively manipulated through both genotypic selection and irrigation management to ensure optimal performance under different levels of soil available water.  相似文献   

3.
Root density of irrigated, field-grown Russet Burbank potatoes grown on Plainfield loamy sand was determined periodically from soil core samples during the 1973 growing season. Total root length and weight also were measured. Under these growing conditions, the roots essentially were restricted to the plow layer in this soil, decreasing rapidly below this depth. The root density in the plow layer generally ranged from 2 to 6 cm of roots per cm3 of soil, with lower values at greater depths. The root density exceeded 6 cm/cm3 in only a few cores, with a maximum of 11 cm/cm3 obtained on one core in the 10 to 20 cm depth adjacent to the plant. Roots with diameter less than 0.2 mm accounted for about two-thirds of the total root length. A decrease in total root length and dry-weight per plant occurred at the end of the growing season, coincident with the usual decrease in foliage dry weight. The root density beneath the furrow was not significantly different from that within the plant row during most of the growing season.  相似文献   

4.
Irrigation and nitrogen management are two of the most important factors affecting production efficiency and environmental quality in potato cropping systems. Field studies were conducted in 1990 and 1991 to determine the interactive effects of irrigation amount and N timing on potato yield, quality and nitrate leaching potential. Sprinkler irrigation was applied at approximately 1.0, 1.2 or 1.4 times estimated evapotranspiration (ET) to Russet Burbank potatoes grown on a silt loam soil. Following tuber initiation, a total of 132 kg N/ha was applied through the irrigation system to N treatment subplots using either six weekly 22 kg N/ha applications or 3 biweekly 44 kg N/ha applications. Excessive irrigation reduced root zone and petiole NO3-N concentrations during substantial portions of the tuber bulking period. Biweekly 44 kg N/ha applications in 1991 produced higher and more consistent earlyseason root zone NO3-N concentrations in the 1.2 and 1.4 ET plots than did the weekly 22 kg N/ha applications. Late-season tuber dry weight, total plant dry weight and plant N uptake were not affected by irrigation rate or N timing. However, excessive irrigation reduced U.S. No. 1 yield and yield of tubers >284 g in both 1990 and 1991 and reduced total yield in 1990. Biweekly N applications produced higher U.S. No. 1 yields than weekly N applications at all irrigation levels. Excessive irrigation also reduced NO3-N remaining in the top 60 cm of soil at the end of the growing season. These results show that irrigating at optimal rates and applying split N at two week intervals on a silt loam soil can maximize Russet Burbank yield and quality while minimizing NO3-N losses.  相似文献   

5.
为明确新疆南部极端干旱区滴灌小麦的灌水量阈值,在常规沟灌(总灌量为3 750 m·hm-2)的基础上,设计了四种减量滴灌模式(灌水量分别为3 376、3 000、2 625和2 250 m·hm-2),分析了滴灌量对冬小麦产量、水氮利用效率及根系分布的影响。结果表明,土壤无机氮残留量因灌水量不同而异,灌水3 376和2 625 m·hm-2时较低;各灌水条件下土壤无机氮残留量均随小麦生育期推进先降后升,在灌浆期达到最高,而后下降。随土层深度的增加,土壤中无机氮含量也逐渐递减。冬小麦水分利用效率随灌水量的增加呈先增后降趋势,灌水量在2 250 ~3 000 m·hm-2范围内,随灌水量的增加,水分利用效率先逐步增加,而后下降。小麦根系长度随灌水量的减少呈递减趋势,当灌水量高于或低于3 000 m·hm-2时,小麦根系出现早衰现象。  相似文献   

6.
不同秸秆还田模式对大豆根系分布的影响   总被引：2，自引：0，他引：2  
对免耕、灭茬还田和传统耕作条件下大豆根系在土壤剖面中的垂直分布的变化规律进行了研究,为改善在保护性耕作条件下大豆根系发育条件提供参考。结果表明,免耕、灭茬还田和传统耕作模式的根长、根表面积、根体积及根干重均主要分布于土壤剖面0～10 cm深度。在0～10 cm深度内,不同耕作模式之间的根体积密度、根干重密度差异显著,其中免耕模式最低。在10～20 cm深度内,免耕模式根长密度、根表面积密度、根体积密度和根干重密度最低,其根长、根表面积、根体积和根干重占土壤剖面比例最低。土壤剖面根长、根表面积、根体积和根干重累加值亦表现为免耕最低,灭茬还田与传统耕作差异不显著。灭茬还田模式的根长密度、根表面积密度、根体积密度及根干重密度与传统耕作差异不显著,同时其根长、根表面积、根体积及根干重的垂直分布与传统耕作间差异亦不显著。土壤机械阻力和根长密度、根表面积密度、根体积密度及根干重密度呈显著负相关,土壤机械阻力是限制免耕模式大豆根系发育的重要因素。  相似文献   

7.
The distribution of length, diameter, surface area and volume of roots was measured in northern New South Wales, Australia, under temperate pasture that had been previously grazed at low and high stocking rates for 30 years; these root characteristics were compared with those of roots under ungrazed pasture. The ungrazed pasture was dominated by Phalaris (Phalaris Aquatica), whereas annual grasses and dicotyledons were a large component of the pasture at low and high stocking rates. A fine-meshed (0.250 mm) sieve was used for separating the roots from the soil, and the root characteristics were measured using image analysis techniques. With this sieve size, root length densities were many times higher than published data for astures where a larger mesh sieve had been used for sample preparation. The lengths of root per unit of soil volume (root length densities) were high for all stocking rates and averaged 91 cm cm?3 near the soil surface (0 – 5 cm) declining to 4.0 cm cm?3 at the deepest depth measured (65–75 cm). There was a greater proportion of roots near the soil surface at the higher stocking rates. A greater proportion of fine roots occurred at the higher stocking rates, which was probably due to the differences in botanical composition. Reciprocal, power and logarithmic functions best described the distribution of root length density, root surface area density and root volume density, root surface area density and root volume desnity with depth.  相似文献   

8.
为总结施氮量与小麦根系生长及产量的关系,通过查询近30年（1993-2019年）中国主要麦区施氮量对小麦根长密度、根干重密度及产量影响的文献资料,对小麦适宜的施氮范围进行分析。结果表明,随着土层的加深,小麦根长密度(RLD) 和根干重密度(RDWD)总体上呈逐渐降低的趋势,且小麦根系主要分布在0～20 cm土层。不同施氮量下0～60 cm土层小麦开花期的RLD 和RDWD均高于成熟期,开花期的RLD 和RDWD分别在施氮220～235和192～209 kg·hm-2时达到最大值,成熟期分别在施氮220～275和 171～212 kg·hm-2达到最大值。经相关性分析,小麦产量与RLD、RDWD均呈显著正相关。通过对施氮量与小麦籽粒产量进行一元二次方程拟合得出,在施氮量为247 kg·hm-2时小麦产量达到峰值。因此,在当前中国主要麦区向农户推荐氮肥用量时,需针对不同区域,结合农田实际,在施氮171～247 kg·hm-2范围选择合理用量,以促进小麦根系的生长发育及籽粒产量的提高。  相似文献   

9.
Water shortage threatens agricultural sustainability in the Huang-Huai-Hai Plain of China. Thus, we investigated the effect of supplemental irrigation (SI) on the root growth, soil water variation, and grain yield of winter wheat in this region by measuring the moisture content in different soil layers. Prior to SI, the soil water content (SWC) at given soil depths was monitored to calculate amount of irritation water that can rehydrate the soil to target SWC. The SWC before SI was monitored to depths of 20, 40, and 60 cm in treatments of W20, W40, and W60, respectively. Rainfed treatment with no irrigation as the control (W0). The mean root weight density (RWD), triphenyl tetrazolium chloride reduction activity (TTC reduction activity), soluble protein (SP) concentrations as well as catalase (CAT), and superoxide dismutase (SOD) activities in W40 and W60 treatments were significantly higher than those in W20. The RWD in 60–100 cm soil layers and the root activity, SP concentrations, CAT and SOD activities in 40–60 cm soil layers in W40 treatment were significantly higher than those in W20 and W60. W40 treatment is characterized by higher SWC in the upper soil layers but lower SWC in the 60–100-cm soil layers during grain filling. The soil water consumption (SWU) in the 60–100 cm soil layers from anthesis after SI to maturity was the highest in W40. The grain yield, water use efficiency (WUE), and irrigation water productivity were the highest in W40, with corresponding mean values of 9169 kg ha?1, 20.8 kg ha?1 mm?1, and 35.5 kg ha?1 mm?1. The RWD, root activities, SP concentrations, CAT and SOD activities, and SWU were strongly positively correlated with grain yield and WUE. Therefore, the optimum soil layer for SI of winter wheat after jointing is 0–40 cm.  相似文献   

10.
K. Iwama 《Potato Research》2008,51(3-4):333-353
Potato roots are concentrated mostly in the plow layer up to 30 cm in soil depth. Some roots extend up to 100 cm depth and the total root length throughout the soil profile reaches about 10–20 km m?2 area. There are large differences in root mass (dry weight and length) in the plow layer between cultivars, breeding lines and wild relatives. The differences are generally stable across different environmental conditions, such as locations with different soil types, fertilizer rates and planting densities. Under favourable environmental conditions without severe shortage of water and nutrients, root mass differences between genotypes are related to maturity class: late genotypes continue root growth longer, and attain larger root mass and deeper rooting than early genotypes. Differences in root mass become clear at the start of flowering, much earlier than differences in shoot mass. Root mass is negatively correlated with early tuber bulking. However, root mass generally shows positive correlations with shoot mass and final tuber yield. Differences in root mass also exist amongst genotypes of the same maturity class. Using root mass in the plow layer and tuber yield as selection criteria, Konyu cultivars were bred in Japan. They showed significantly less reduction of leaf conductance and photosynthesis, leaf area and tuber yield than commercial cultivars under dry soil conditions. To assist breeding for root characters, new methods have been developed to assess the ability of roots to penetrate into hard soil layers using pots with paraffin-vaseline discs and the ability to absorb under low water potential in vitro. Physiological research on root characteristics contributed in the past, and will continue to do so in the future, to the development of new cultivars with high drought tolerance and to the improvement of irrigation practice.  相似文献   

11.
Drip irrigation in dry-seeded rice (DSR) is a new water-saving cultivation technology; however, very little is known of its productivity and water-saving capacities. The study was conducted for 2 years (2013 and 2014) in a split-plot design in three replicates with treatment combinations of four irrigation regimes [drip irrigation at 1.5, 2.25, and 3.0× pan evaporation (Epan) and flood irrigation at 3.0× Epan] and three nitrogen (N) levels (120, 150, and 180 kg ha?1). Drip irrigation in DSR resulted in higher grain yield (7.34–8.01 t ha?1) than flood irrigation (6.63–7.60 t ha?1) , with water savings of more than 40 %. Water-use efficiency with drip irrigation was higher (0.81–0.88 kg m?3) than flood irrigation (0.42–0.52 kg m?3) , being highest with drip irrigation at 1.5× Epan. Root density at soil depths of 15–30 cm was also higher in drip (0.86–1.05 mg cm?3) as compared to the flood (0.76–0.80 kg m?3)-irrigated crop. This study implicated that under water-scarce scenario, drip-irrigated DSR is a profitable, and water- and energy-saving technology. This study also suggested that policy focus in future must be tilted towards the promotion of solar-operated drip irrigation in those regions, where DSR is being promoted in the face of water and energy crisis.  相似文献   

12.
大垄栽培条件下的土壤环境与马铃薯产量   总被引：7，自引：3，他引：7  
试验进行了大垄与小垄两种栽培模式下的一些土壤环境因子及马铃薯产量的差异研究,结果表明:大垄栽培改善了结薯区及根区的土壤生态环境,使该区的土壤容重和出苗后10￣25cm耕层土壤温度显著降低;使20￣30cm土壤含水量显著地增加;促进了养分释放;大垄栽培相对于小垄使马铃薯总产量和商品薯产量明显增加,且均达到极显著水平。大垄栽培使总产增加24.31%,商品薯产量增加得更大,达到61.74%。大垄栽培是可以在黑龙江省大范围推广的栽培方式。  相似文献   

13.
Significant increases in pre-emergence seedpiece decay and preemergence shoot infection were observed asErwinia carotovora var.atroseptica inoculum density increased. As inoculum density increased, a point was reached where virtually 100 per cent of the disease was expressed as preemergence decay and no typical postemergence blackleg occurred. Soil temperature and soil moisture markedly affected blackleg incidence, especially at low inoculum densities. Increasing soil temperature (from O°C to 30°C) and soil moisture (from 65 to 100% of field capacity) usually resulted in an increased total blackleg incidence. The effect of soil temperature and soil moisture appeared to be masked at high inoculum densities. Conditions such as low inoculum density and/or cool soil temperatures and low soil moistures which apparently slowed the rate of seedpiece decay usually increased the amount of postemergence blackleg, but also reduced the total amount of disease which occurred. It is suggested that conditions which are not optimal for the pathogen result in increased amounts of typical easily diagnosed postemergence blackleg expression, whereas conditions which favor the pathogen may reduce this phase of the disease but actually increase the total loss by increasing the amount of seedpiece decay and preemergence death of potato shoots.  相似文献   

14.
不同灌溉方式对春玉米根系分布、养分累积及产量的影响   总被引：2，自引：2，他引：0  
通过田间试验,研究不同灌溉方式下东北中部春玉米区土壤结构、根系形态、地上部养分累积及产量构成。结果表明,灌溉后土壤三相比显著变化,土壤固相下降,液相和气相比例显著增加,0～20 cm土壤容重降低6.7%～17.9%;灌溉后0～60 cm根系干重及根长总量略有增幅,且在深层土壤中的比例增加,有利于植株对养分和水分的吸收;与不灌溉（CK）相比,隔沟交替灌溉（T1）、全垄灌溉（T2）下植株氮、磷、钾含量平均提高14.5%、42.6%、16.1%,生物量和产量平均提高19.8%和14.3%。因此,在春玉米关键生育期合理补水可以改善土壤结构,降低土壤容重,促进根系合理分布,增加植株养分吸收,进一步增加产量。  相似文献   

15.
Drip as Alternative Irrigation Method for Potato in Florida Sandy Soils   总被引：2，自引：0，他引：2  
Seepage irrigation is the most common irrigation system for potato production in Florida, which relies on control of the water table to irrigate the crop. A 2-year trial was established to evaluate the feasibility of drip irrigation as an alternative to seepage for potato production. The performance of ‘Atlantic’, ‘Fabula’, and ‘Red LaSoda’ varieties were evaluated by comparing two drip tape installation depths, surface (SUR) and subsurface (SUB) with seepage (SEP). The overall potato total yield was 25.3; 19.2 and 29.9 Mg ha?1 for SUR, SUB and SEP, respectively. The SUR and SEP treatments yielded similarly for ‘Fabula’ in both years and ‘Atlantic’ in 2011. The ‘Red LaSoda’ consistently obtained lower yields under both drip treatments compared to SEP. Conversely, drip irrigation promoted significant reduction of the incidence of tuber physiological disorders such as brown center, hollow heart, and internal heat necrosis.  相似文献   

16.
Nitrate () leaching is an environmental and health concern. In grazed pasture systems, leaching primarily occurs beneath animal urine patch areas due to high nitrogen (N) loading and the inability of pasture plants to capture all of this N. This study investigated the relative importance of plant growth and root architecture to recover soil N. Herbage N recovery, dry matter (DM) yield and root architecture, following injections of 15N‐enriched urea at different soil depths (5, 25 and 45 cm), were measured for Italian ryegrass (Lolium multiflorum Lam.) and tall fescue (Festuca arundinacea Schreb.) grown in soil monolith lysimeters (18 cm diameter × 70 cm depth) under simulated South Island, New Zealand winter temperature and light levels. Total herbage N uptake and DM yield were on average 24 and 48% greater in L. multiflorum than F. arundinacea respectively. Root length density (cm cm?3 soil) in the 5‐ to 25‐cm‐depth horizon was similar between species. In the 25‐ to 45‐cm‐depth horizon, F. arundinacea roots were found at higher densities than L. multiflorum. In the 45‐ to 65‐cm‐depth horizon, root length density was fourfold to ninefold higher for F. arundinacea than L. multiflorum, but N uptake efficiency was greater in L. multiflorum (0·48 mg 15N m?1 root) than F. arundinacea (0·09 mg 15N m?1 root). The results suggest that deep F. arundinacea roots are relatively inactive during the winter period and confirm that plant growth is more important than root architecture (e.g. deep roots) to recover soil N and ultimately reduce nitrate leaching losses.  相似文献   

17.
Root functional traits (RFTs) are crucial for understanding nutrient cycling processes. However, seasonal variation of RFTs and their potential changes in root foraging pattern have been almost ignored in field studies. In this work, belowground net primary production (BNPP, g m?2), root length density (RLD, km m?2), specific root length (SRL, m g?1), root N concentration and C/N ratio in defoliated grass‐clover swards of different sward ages and receiving different cattle slurry levels were investigated for 2 years. All measured RFTs showed significant seasonal variation: in general, seasonal variation was most marked between primary growth period (until heading stage of perennial ryegrass) and subsequent regrowth periods following defoliation; meanwhile, the rooting pattern also differed. These phenomena were not affected by current management or sward composition, but were correlated with plant C availability. Daily BNPP and RLD rates varied 7‐ to 8‐fold in the growing season. Moreover, BNPP and RLD were asynchronous due to seasonal variation in SRL. Rooting pattern and the relationship with shoot phenology are discussed. We conclude that root functional traits vary with season; thus, roots which develop in different seasons may be involved in belowground nutrient cycling processes with different turnover characteristics; trade‐off among traits may also involve temporal variation. Root‐C related investigations in grass‐clover swards should include root mass sampling rather than use of root length observations alone.  相似文献   

18.
施氮量对新疆滴灌冬小麦根系生长及产量的影响   总被引：1，自引：0，他引：1  
为探明滴灌冬小麦高产需氮肥规律,利用大田试验研究了N_0(0 kg·hm~(-2))、N_1(90kg·h~(-2))、N_2(180kg·h~(-2))、N_3(270kg·h~(-2))、N_4(360kg·h~(-2))施氮量对新冬18号0~60cm土层根系生长的影响及其与产量和氮肥利用率的关系。结果表明,随着施氮量的增加,拔节至成熟期间0~60cm土层根系干重、根长和根系活力均增加,N_3处理孕穗期小麦0~60cm土层根干重、根长分别较N_0处理增加11.93%、29.0%,增幅基本表现为0~20cm20~40cm40~60cm土层;N_3处理较N_0处理小麦产量增加30.35%,氮肥农学利用效率为6.90kg·kg-1。拔节期前后施适量氮肥可促进0~60cm土层根系生长和活力增强,是氮肥增产的重要原因。本试验条件下最适宜施氮量为180~270kg·h~(-2),可获得产量7 591.49~8 004.85kg·h~(-2),氮肥农学利用效率为6.90~8.06。  相似文献   

19.
有序摆抛栽超高产栽培对水稻根系形态生理特征的影响   总被引：2，自引：0，他引：2  
为研究不同抛栽方式对水稻根系形态生理的影响,探索抛秧稻超高产轻简栽培新途径,以粳型超级稻武运粳24和南粳44为试验材料,设置摆栽、点抛和撒抛三种抛栽方式,并以机插为对照,系统研究了有序摆抛稻根系的形态和生理特征。结果显示,水稻有序摆栽和点抛后秧苗根系长度、根数、单株根质量高于撒抛和机插,栽后7 d 3连孔稻苗优势明显,栽后15d2连孔秧苗表现出较强的优势。各生育时期群体根干质量、根冠比、根系活力表现为摆栽点抛撒抛机插,不同连孔稻株间表现为2连孔3连孔单孔,根系吸收总面积、活跃吸收表面积和吸收面积比与穗后根系伤流量亦呈现相同趋势。各生育时期的根系干质量、根冠比、根系活力及抽穗期单茎根系伤流量、根系吸收表面积、活跃吸收表面积、活跃吸收比与产量极显著相关。齐穗后15d,70%以上根系分布在0~5cm,90%以上根系分布在0~10cm,各层根干质量、根体积、根干质量密度抛栽方式间表现为摆栽点抛撒抛,不同连孔处理间为2连孔3连孔单孔,5~10cm、10~15cm、15~20cm的根系比例亦呈现此趋势。0~20cm内,各层根系干质量、根系体积、根干质量密度与产量极显著相关,上层根系对产量贡献较大,0~10cm贡献率达90%以上。总之,水稻有序摆抛栽根系发生快,各生育期活力强,后期分布合理,其良好的根系特性是超高产形成的生理基础。  相似文献   

20.
Information is required on nitrogen (N) fertility and seedpiece management for new cultivars and advanced breeding lines. Interactions amongst N fertilizer rate, genotype, and seedpiece spacing are complex, and can affect tuber yield, quality, and storability as well as N fertilizer efficiency. A field study was carried out in 2001 and 2002 at MSU Montcalm Research Farm in central Michigan. Tuber yields and post-harvest quality characteristics were evaluated for five potato genotypes (MSG227-2, MSE192-8Rus, Jacqueline Lee, Liberator, and Snowden) in response to a factorial combination of three N levels (200 kg N ha-1, 300 kg N ha-1-, and 400 kg N ha-1) and two seedpiece spacings, narrow (0.20 m or 0.25 m) and wide (0.33 m or 0.38 m). Narrow seedpiece spacing consistently produced the highest U.S. No. 1 yields in all genotypes tested (37 and 34 t ha-1, narrow vs wide spacing, respectively). There was a tradeoff between seedpiece spacing and N level in 2001 as tuber yields were enhanced by higher N levels at wide seedpiece spacing, but not at narrow spacing. In 2002, tuber yield was not enhanced, but petiole nitrate-N and tuber-N increased as N fertilization increased. Genotype was the major factor that influenced tuber quality characteristics at harvest and for stored tubers (e.g., specific gravity, internal defects, bruising, chip color rating, sucrose, and glucose). Spacing had minimal effects, whereas higher levels of N slightly reduced specific gravity both years, reduced internal defects in 2001 and enhanced sucrose at harvest in 2002. The cultivars tested demonstrated excellent storage characteristics for different N fertility levels and seedpiece spacing combinations. Overall, the recommended N fertilizer level for moderately long-duration potato cultivars in Michigan (200 kg N ha-1) and a narrow seedpiece spacing optimized yield and tuber quality performance while conserving N fertilizer.  相似文献   

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