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1.
Nitrogen fertilizer practices affect nitrous oxide (N2O) emissions from agricultural soils. The “4R” nutrient stewardship framework of using N fertilizer at the right rate, right source, right placement and right time can reduce N2O emissions while maintaining or improving yield of field crops, but understanding of how the various factors affect N2O emissions from irrigated processing potato is lacking. We examined the effects of selected 4R practices on emissions, using results from two irrigated processing potato studies each conducted in 2011 and 2012 in Manitoba, Canada. Experiment 1 examined combinations of source (urea, ESN), placement (pre-plant incorporation [PPI], banding), and rate (100 and 200 kg N ha-1) on a clay loam soil. Experiment 2 examined timing and source treatment combinations (urea PPI, ESN PPI, urea split, urea split/fertigation) on a loamy fine sandy soil. For Experiment 1, use of ESN at 200 kg ha-1 did not reduce area-, yield- and applied fertilizer N- based N2O emissions compared to urea at 200 kg ha-1, irrespective of placement. Emissions from pre-plant banding ESN at 200 kg ha?1, however, were 32% lower than from PPI ESN. For Experiment 2, compared to single pre-plant urea application, fertigation simulated by in-season application of urea ammonium nitrate (UAN) gave lower area-, yield- and applied fertilizer N- based emissions. Split urea ( \( \raisebox{1ex}{$2$}\!\left/ \!\raisebox{-1ex}{$3$}\right. \) pre-plant, \( \raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$3$}\right. \) hilling) also reduced area- and yield- based N2O emissions compared to single pre-plant urea application. Emissions were generally lower at the site with loamy fine sandy soil than the site with clay loam soil. These results demonstrate that combinations of “4R” practices rather than source alone are best to achieve reductions in N2O emissions from irrigated potato production.  相似文献   

2.
Application time of nitrogen (N) fertilizer can significantly influence the yield and quality of potato tubers. The objective of this experiment was to assess the effects of N application time on dry matter accumulation in foliage and tubers, as well as on marketable tuber ratio, dry matter concentration, and specific gravity of the Chinese cultivar KX 13. The four treatments were as follows: all the 150 kg?N?ha?1 applied at planting (T1); 100 kg N ha?1 applied at planting and 50 kg N ha?1 applied 1 week before tuber initiation (20 days after emergence, DAE) (T2); 100 kg N ha?1 applied at planting and 50 kg N ha?1 applied 1 week before tuber bulking stage (35 DAE) (T3); and 100 kg?N?ha?1 applied at emergence and 50 kg N ha?1 applied 1 week before tuber bulking stage (35 DAE) (T4). For all treatments, 90 kg P2O5 ha?1 ((NH4)2HPO4) and 150 kg K2O ha?1 (K2SO4) were applied at planting. Thirty tons per hectare of marketable tuber yield was achieved with T3, while 23 t ha?1 marketable yield was achieved by applying all 150 kg N ha?1 at planting (T1). Relative to treatment T1, T3 also significantly increased harvest index (HI) from 0.76 to 0.86 and marketable tuber ratio from 64.8% to 79.2%. Applying N at planting in conjunction with dressing at 20 DAE (T2) gave a high marketable tuber ratio (74%) and HI (0.86), but the lower total tuber yield led to a lower marketable tuber yield. Without N application at planting (T4), N dressing did not increase the yield and HI. Treatments with N dressing had no significant effect on specific gravity or dry matter concentration of tubers.  相似文献   

3.
The objective of the research was to determine the economic optimum nitrogen (N) fertilization rates and to determine the effects of N fertilization rates on tuber characteristics and fresh mass loss after storage under cold and ambient conditions of four potato cultivars, Ágata, Asterix, Atlantic, and Monalisa. The experiments were, simultaneously, conducted in the same area and similar experimental conditions during the fall/winter period in Viçosa, Minas Gerais State, Brazil. In each experiment, five N fertilization rates (0, 50, 100, 200, 300 kg ha?1) were evaluated in a randomized complete block design. For all cultivars, increasing N fertilization rate increased total and marketable yields and tuber dry matter yield up to a maximum following a quadratic model. Increasing N fertilization rate linearly increased the tuber protein concentration of Atlantic and Monalisa and had no effect on tuber pH. N fertilization rate effects on tuber mass, tuber titratable acidity, and fresh mass loss during storage were cultivar-dependent. N use efficiency (tuber yield divided by N fertilization rate) decreased with increase in N fertilization rate. The economic optimum N fertilization rates ranged from 147 to 201 kg ha?1 depending upon cultivar and relative prices of N and potato tubers. Depending on the cultivar, under favorable price conditions (low N price and high tuber price), the economic optimum N fertilization rates to be applied by potato growers were 92–95% of the estimated N fertilization rate for obtaining the maximum potato yield, whereas under unfavorable conditions (high N price and low potato tuber price) the economic optimum N fertilization rates to be applied should be decreased to 86–92% of the rates for maximum yield.  相似文献   

4.
Previous research suggests that field greening of potato tubers can be minimized by planting seedpieces at an appropriate depth along with sufficient hilling to minimize exposure to sunlight. The appropriate planting depth and hilling practices to minimize field tuber greening have not been determined for newer cultivars. Two separate studies, each conducted for three years, are reported here. The first measured the effect of seedpiece planting depth on the yield, quality, and field greening tuber yield of ‘Russet Burbank’, ‘Frontier Russet’, and ‘Shepody’ potatoes. Seedpieces were handplanted in pre-formed hills at 8, 15, or 23 cm measured from the top of the seedpiece to the top of the hill. Planting at 23 cm resulted in significantly lower total yield compared with the 8- and 15-cm depths for Russet Burbank and Frontier Russet, but planting depth did not affect total yield of Shepody. U.S. No. 1 yield of Russet Burbank was not affected by planting depth, but U.S. No. 1 yield of Frontier Russet was significantly less at the 23-cm depth. For Shepody, the 8-cm depth caused a significant reduction in U.S. No. 1 yield compared with the 15-cm depth. Field greening tuber yield of Russet Burbank was significantly less at the 23-cm planting depth compared to 8 cm. For Frontier Russet and Shepody, planting at 15 or 23 cm resulted in significantly less field tuber greening compared to the 8-cm depth. The second experiment examined the effects of planting depth and hilling practices on yield, quality, and field tuber greening of Russet Burbank and Gem Russet potatoes. Six planting depth and hilling treatment combinations were used. Seedpieces were planted at a depth of either 8 or 15 cm, then hilled to either 15 or 23 cm at emergence or after plants had formed a rosette of leaves approximately 10 cm in diameter (post-emergence hilling). At-emergence hilling treatments had no effect on total or U.S. No. 1 yields of Russet Burbank compared with the 15-cm planting depth, non-hilled control. However, all post-emergence hilling treatments significantly reduced Russet Burbank total and U.S. No. 1 yields. Planting Russet Burbank at 8 cm and hilling to 23 cm at emergence, or planting at 8 or 15 cm and hilling to 23 cm post-emergence reduced field tuber greening of Russet Burbank. The effects of planting depth and hilling on Gem Russet total and U.S. No. 1 yields were less definitive than for Russet Burbank, and no treatments significantly reduced field tuber greening yield compared with the control.  相似文献   

5.
近年来,滴灌节水农业技术及其与灌溉设施相配套的水肥一体化技术在乌兰察布马铃薯生产中的应用越来越广泛。但实际生产中,种植者常因将杂质含量大、难溶解的常规肥料应用于滴灌系统,而造成滴头堵塞。液体肥料具有溶解性好、杂质少等优点,是利用滴灌设施进行追肥的理想肥料。在田间试验条件下,研究了在适量降低基肥用量的同时,通过每667m2滴灌追施10、20、30kg农季高液体肥对马铃薯生长、产量及商品性状的影响。结果表明,追施农季高液体肥处理比传统追肥处理增产显著,马铃薯块茎产量增幅达13．52％-22．36％,商品率提高4．68％-6．55％,每667m2增收401．85-527．95元,经济效益显著提高。表明农季高液体肥可以在马铃薯作物上推广应用。  相似文献   

6.
密度和钾肥对马铃薯品种东农306产量的影响   总被引：5，自引：5，他引：0  
以特用型马铃薯品种"东农306"为材料,在2003～2004年进行了种植密度与钾肥用量对产量的影响试验。结果表明,该品种在不同种植密度与钾肥用量下单株产量差异显著,在本试验中以行距70 cm和株距30 cm的密度、硫酸钾用量150 kg·hm~(-2)最适合该品种的个体生长,能获得较高的单株产量和商品薯产量;行距70 cm和株距20 cm的密度、硫酸钾用量75 kg·hm~(-2)最适合该品种的群体生长,能获得较高的群体产量和商品薯产量。  相似文献   

7.
Use of nutrient efficient crop species or cultivars within species in combination with improved crop production practices offer the best option for meeting the future food requirements of growing world populations. Efficiency improvement has a key role for nutrient use and it improves both productivity of yield and minimizes risks of losses that potentially harm the environment. To improve nutrient use efficiency (NUE), one strategy is to select cultivars of crops with high NUE. Both nitrogen (N) and phosphorus (P) are among essential macronutrients commonly applied to agricultural crops to optimize yields. Evaluation of potato cultivars with high N and P efficiency is essential for sustainable production of the crop. In Ethiopia, however, little research has been done to elucidate better NUE of potato crop until recently. This study was, thus, designed to evaluate selected potato cultivars (Belete, Gudene, Jalene, Marachere and one local check) for NP use efficiency under low levels of the nutrients in Wolaita Sodo University, Ethiopia during 2014 and 2015. Factorial combination of 3 levels of each N (0, 55.5 and 111 kg N ha?1 ) and P (0, 19.5 and 39 kg P ha?1 ) were assigned to the main plots and the 5 cultivars to subplots of split-plot design in three replications. Efficiency indices such as agronomic efficiency, physiological efficiency and recovery efficiency were computed for combined NP nutrients. Results showed that agronomic nitrogen use efficiency, apparent phosphorus use efficiency and phosphorus use efficiencies were significantly influenced by the interaction effect of rates of NP nutrition and variety. Application of NP more than 55.5:19.5 kg ha?1 will not beneficial due to their less or equal use and recovery efficiencies to 55.5:19.5 kg NP ha?1. Belete was the most NP efficient variety followed by Jalene and Gudene in all efficiency indices. Therefore, Belete, Jalene and Gudene return better for NP at 55.5:19.5 kg ha?1 for economical use of fertilizes while obtaining satisfactory yield. It can be concluded that yield response variation of the varieties was related to their differences in NP uptake and use efficiencies; and the improved potato varieties were superior to local check in using NP nutrients efficiently.  相似文献   

8.
腐殖酸氮磷钾复合肥单一施用或与尿素配合施用，马铃薯的商品率和淀粉含量均比对照显著或极显著提高．综合考虑，单一施用是最佳处理，在马铃薯生产中，可以推广使用这种肥料．  相似文献   

9.
New cultivars ‘Alpine Russet’, ‘Dakota Trailblazer’ and ‘Ivory Crisp’ have lower tuber reducing sugars and acrylamide-forming potential. Adoption of new cultivars by growers requires information about their responses to agronomic factors such as nitrogen (N) fertilizer. The objective of this study was to determine the effect of N rate on yield and quality of new cultivars relative to conventional cultivars ‘Russet Burbank’ and ‘Snowden’. The experiment was conducted over two years as a randomized complete block design replicated four times with five N rates and five cultivars. The new cultivars had comparable or higher marketable yields, and a higher percentage of large tubers (greater than170 g) than the standard cultivars. Total and marketable yields responded quadratically to N and optimized at 231 kg ha?1 in 2011 and 319 kg ha?1 in 2012 for all cultivars. ‘Dakota Trailblazer’ had high hollow heart incidence (greater than 10% at N rates above 125 kg ha?1), and excessively high specific gravity, making it undesirable for processing but with potential to be a parent in a breeding program. ‘Alpine Russet’ and ‘Ivory Crisp’ had specific gravity suitable for commercial processing, and low hollow heart incidence at all N rates. Critical petiole nitrate-N concentrations 50 and 70 days after planting for all cultivars were greater in 2012 than in 2011, suggesting that interpretation of critical values can be affected by growing conditions.  相似文献   

10.
Allagash Russet, BelRus, Frontier Russet, HiLite Russet, Russet Norkotah and Russet Burbank were evaluated with preplant N fertilizer levels of 0, 67, 134, 201, and 201 kg N/ha in a split application on a Knik silt loam in 1990 and 1991 near Palmer, Alaska. BelRus and Russet Norkotah yielded less marketable tubers than the other cultivars and Russet Burbank performed well under warm, dry 1990 conditions and poorly when conditions were cool and wet (1991). Allagash, HiLite and Frontier Russets were consistent producers with marketable tuber yields averaging 35.4, 32.3, and 32.2 t/ha, respectively. Marketable tuber yield was maximized with approximately 175 kg total N/ha (residual soil plus applied) and approached 43 t/ha in 1990. Splitting the N application had no significant effect on tuber yield. Newly released russets appear promising for commercial Alaska producers.  相似文献   

11.
Fertilizer nitrogen (N) may be managed to increase crop production and profitability while reducing nitrate contamination of groundwater. A two-year field investigation was conducted to evaluate the effects of applied N on tuber yield and quality, dry matter production and N uptake of potato (Solanum tuberosum L. var. Russet Burbank) grown on irrigated sandy soils in Michigan. Nitrogen was applied as ammonium sulfate [(NH4)2SO4] at rates of 0, 56 and 112, kg N ha?1 in a single application at planting or 112 and 168 kg N ha?1 in split applications during the growing season. Total tuber yield generally increased with N applications up to 112 kg N ha?1. Only one of the three experimental sites showed an increase in marketable tuber yield when 112 kg N ha?1 was split evenly between planting and tuber initiation. Tuber specific gravity was not affected by N rate. Nitrogen rates of 112–168 kg N ha?1 maximized dry matter production and plant tissue N concentration at onset of maturity and harvest. Tuber N concentration at harvest ranged from 13–17 g kg?1 at two of the three locations. Values for the third experiment were 10–13 g N kg?1. Whole crop N uptake at onset of senescence ranged from 45 to 225 kg N ha?1 across all locations and treatments. An average of 67 percent of this N was found in tubers at harvest. Nitrogen fertilization exceeded N removal in harvested tubers by more than 50 kg N ha?1 only for the 168 kg N ha?1 treatment. These results indicate that acceptable tuber yield can be obtained with lower N rates than those currently used by most producers, with the potential for reducing net loss of N from the soil.  相似文献   

12.
Research has shown that while fumigation and use of ammonium N can both reduce the severity of verticillium wilt (Verticillium dahliae Kleb.) of potatoes (Solanum tuberosum L.), the use of the two practices together raises concerns over feeding the crop only ammonium N under reduced nitrification conditions. To assess the validity of this concern, we conducted two 3-year field split-plot experiments with both using metam sodium fumigant (none, fall or spring applied) as the main plot. For the first experiment, N source (134 kg N ha?1 as ammonium sulfate, urea, or ammonium nitrate) was the split, whereas for the second trial in-season N rate (0, 67, 134, or 202 kg N ha?1 all as ammonium sulfate) was the split. For both trials, in 2 of the 3 years, fumigation significantly increased tuber yield by an average of 9.9 Mg ha?1 and decreased late-season verticillium severity ratings from 77 to 45%. In some years, fumigation also increased the proportion of U.S. No. 1 tubers and tubers >170 g. No differences in crop yield or quality were observed between the various N sources applied. This was true even on spring-fumigated areas with the highest rate of ammonium N applied. These experiments confirm that the choice between in-season potato N fertilizer should be based on factors such as potential for benefits or N losses, cost, and convenience of use rather than concern over an interaction between fumigation and ammonical N. While both fumigation and N rate reduced verticillium severity ratings in some years, the lack of interaction suggests these factors are functioning independently.  相似文献   

13.
追施不同肥料对马铃薯品种抗疫白产量的影响   总被引：1，自引：1，他引：0  
为探究追施对马铃薯品种抗疫白产量的影响,设计4个处理,每667 m2施①基肥:二铵16 kg+尿素15 kg+硫酸钾15 kg(对照);②基肥:二铵16 kg+尿素8.6 kg+硫酸钾15 kg,追肥:尿素6.4 kg(追氮区);③基肥:二铵16kg+尿素15kg+硫酸钾7.5kg,追肥:硫酸钾7.5kg(追钾区);④基肥:二铵16kg+尿素8.6kg+硫酸钾7.5 kg,追肥:尿素6.4 kg+硫酸钾7.5 kg(追氮、钾区)。结果表明,追施钾肥的产量最高,其次是追施氮肥和钾肥,但二者差异不显著,排在第三位的是追施氮肥,不追肥的产量最低,但追施氮肥和钾肥的商品率最高。  相似文献   

14.
The area grown with processing potato crops in the Argentinian Pampas has been increasing steadily since 1995. The aim of this work was to assess the effects of N, P and S upon yield and tuber quality and their impact on CO2 emissions assessed with the Cool Farm Tool-Potato. During the spring-summer growing seasons 2008/2009 and 2009/2010, ten fertilization experiments to individually assess N, P and S effects were carried out in the southeast region of the Argentinian Pampas. Nitrogen (four N rates), phosphorus (four P rates) and sulfur (three S rates) were applied at planting and tuber initiation; at combined rates of 0, 50, 100 and 150 kg N ha?1, and at rates of 0, 25, 50 and 100 kg P ha?1 and 0, 10 and 20 kg S ha?1. N and P had a positive effect on total tuber yield, but tuber dry matter concentration (DMC) decreased at higher N rates. The fraction of marketable tubers suitable for processing into French fries increased with the addition of N, showed no variations with P fertilization, and decreased when S was applied. French fry colour, length/width (L:W) ratio and tuber defects were not affected by N, P and S fertilization. With regard to CO2 emissions assessed with the Cool Farm Tool-Potato, results showed that the higher the N rates the higher the CO2 emissions, but they decreased at higher yields. P and S rates did not have an impact on the CO2 emissions, which also decreased at higher yields. Under the production system of the Pampas, N should be split between planting and tuber initiation, and intermediate P rates should be applied all at planting, in order to improve crop yield and quality and to reduce CO2 emissions.  相似文献   

15.
马铃薯施肥肥效及养分利用率的研究   总被引：32，自引：4，他引：28  
对6年14项次的马铃薯氮磷钾肥肥效试验,研究了施用氮磷钾化肥对马铃薯的增产效果、肥料利用率和施肥对淀粉含量的影响。结果表明,增施氮肥(N)平均增产21.3%,每千克N增产马铃薯37.9kg;增施磷肥(P2O5)增产18.4%,每千克P2O5增产马铃薯51.8kg;增施钾肥(K2O)平均增产15.3%,每千克K2O增产马铃薯35.9kg。总的增产效果:氮肥>磷肥>钾肥。14项次试验中增施氮肥的肥料利用率(N)为24.3%～45.2%,平均32.9%;增施磷肥的肥料利用率(P2O5)为7.5%～20.9%,平均14.8%。增施钾肥的肥料利用率(K2O)为38.3%～92.6%,平均49.8%。平均生产1t马铃薯吸收N为6.15kg,吸收P2O5为1.36kg,吸收K2O为6.17kg。马铃薯淀粉含量旱地明显大于水浇地。减N处理马铃薯淀粉含量最高,其次是NPK配合处理。  相似文献   

16.
Surface water runoff from the hill, where potatoes are planted, to the furrow may exacerbate potato drought sensitivity. Planting into furrows and constructing midrow ridges may improve water use efficiency and relieve water stress on potato by directing water toward, not away from, the plants. A 3-year field study was conducted to compare yields and tuber size distributions of furrow- and hill-planted potato (Solanum tuberosum L., ‘Russet Burbank’) on coarse-textured, well-drained soils under sprinkler irrigation. A split-plot experimental design with main plots of row orientation (N-S vs E-W) and subplots of planting method (hill and furrow) combined with two planting depths was used at two central North Dakota sites. Except for planting method and limiting the post-emergence cultivation in the furrow treatments, all cultural practices (fertilizer, irrigation, etc.) were identical and corresponded with conventional practices for hill planted potato. Row orientation did not affect yield for any tuber size category. Averaged over 3 years, furrow-planted potato produced 24% larger tubers (188 vs 151 g), 31% smaller yield for tubers <113 g (4.99 vs 7.21 Mg ha?1), 28% smaller yield for tubers 113 to 170 g (8.14 vs 11.3 Mg ha?1), 8% larger yields for tubers 170 to 283 g (18.0 vs 16.6 Mg ha?1), 103% larger yields for tubers 283 to 454 g (10.9 vs 5.36 Mg ha?1), 341% larger yields for tubers >454 g (2.65 vs 0.60 Mg ha?1), and 10% larger total yields (46.2 vs 41.9 Mg ha?1) compared with hill-planted potato. There were no differences in tuber specific gravity. Preliminary soil water measurements indicated an inter-row water-harvesting effect for furrow planting compared with hill planting. The furrow-planting method may offer significant potential for ameliorating the drought sensitivity of potato.  相似文献   

17.
Maximising potato nitrogen use efficiency (NUE) is necessary to combine high yields, market requirements, high economic income and low environmental impact. A 5-year study was conducted to assess the cultivar effect on NUE components in France. Seven trials were carried out in the Beauce, Picardie and Nord-Pas de Calais regions. The protocol combined two factors: cultivar (‘Agata’, ‘Bintje’, ‘Innovator’, ‘Lady Claire’ and ‘Spirit’) and nitrogen application along a complete response curve (six to seven rates). Total tuber yield, 50 mm tuber yield and nitrogen uptake at haulm killing were measured. We demonstrate that the potato cultivar has a clear effect on NUE components. This effect is supported both by nitrogen uptake efficiency (NupE) and by nitrogen utilisation efficiency (NutE). It implies that the potato cultivars tested generate different nitrogen requirements per yield unit to reach the optimum yield. The way to characterise these differences for all cultivars available in registration trials must be considered before taking into account a cultivar effect on NUE in nitrogen recommendations for farmers.  相似文献   

18.
Potato tuber tissue is low in calcium as compared to leaves and stems. Several recent studies have provided evidence linking tuber quality with tuber tissue Ca concentration. The purpose of the present study was to determine the influence of supplemental Ca and N fertilization on tuber Ca concentration and internal brown spot of potato. Three soluble products (calcium nitrate, calcium chloride, and N-Plus; 9N:0K:0P:11Ca) were used as Ca sources with and without gypsum. In addition, a combination of calcium chloride, urea, and calcium nitrate (CUC) was also used without gypsum. Each treatment consisted of five replications, which received the same total amount of N (252 kg ha?1) supplied either alone or in various combinations of ammonium nitrate, urea, calcium nitrate, calcium chloride, and N-Plus. The soluble sources of Ca were added at 68.8 to 168.0 kg ha?1 while gypsum supplied Ca at 49 kg ha?1. The application of all N by hilling (non-split) was compared to split application of N and Ca at hilling and 2, 4, and 6 wk after hilling. Tubers were mechanically harvested and graded according to industry standards. About 100 U.S. No. 1 tubers from each replication were cut in half along the longitudinal axis and visually inspected for internal defects. From each replication, non-periderm tissue from 15 tubers was combined for Ca analysis. There was no treatment effect on tuber yield in both years. Application of gypsum, either alone or in combination with the soluble sources, was not effective in reducing incidence of internal brown spot (IBS). Furthermore, with one exception, application of gypsum either alone or in combination with soluble sources of Ca was not effective at increasing tuber tissue Ca concentration. Combined analyses of data from 2 years showed that the application of soluble sources of Ca without gypsum increased tuber Ca concentration and decreased the incidence of IBS. Furthermore, split application of N had similar beneficial effects as compared to non-split N. Data from 1997 (a year with high IBS) gave a significant inverse relationship between tuber Ca and IBS, suggesting that an increase in tuber Ca can reduce IBS incidence.  相似文献   

19.
Growing potatoes from cuttings for seed and table potato production has great potential in Asia. There is limited information available explaining the agronomic methodology of growing cuttings in the field. This research was conducted to assess the importance of 4 management variables on the growth and tuber yield of cuttings. Three planting systems were evaluated with and without hilling. Only hilling significantly improved yields and increased tuber number per plant by 50%. Hilling also reduced tuber greening. Increasing plant population from 40,000 to 100,000 per hectare resulted in a yield increase of at least 50%, however average tuber size decreased. Pruning of the apical shoot at or after transplanting did not improve branching, canopy cover or tuber yield. Yields from cuttings were equal to or greater than the tuber seed grown control treatments. Yields ranged from 15 to 20 t/ha which is acceptable for the warm growing conditions. These results show the potential of using cuttings in commercial growing of potatoes in the warm tropics where tuber seed is difficult to obtain and maintain.  相似文献   

20.
Nitrogen fertilizer efficiencies on potatoes   总被引：1，自引：0，他引：1  
Nitrogen fertilizer efficiencies must be known to successfully apply N fertilizer according to crop growth needs. The objective of this study was to determine the recovery, partitioning, and translocation of N fertilizer applied at different times for potato production. Russet Burbank potatoes were fertilized preplant with15N-depleted ammonium sulfate, and during early and late tuber growth with urea containing K15NO3 in 1978 or (15NH2)2CO in 1980. All N applications increased tuber yields above the control treatments. The N recovery efficiency was 60% for the preplant N application, and over 80% and near 60% for the N applications during tuber growth in 1978 and 1980, respectively. Good agreement was found between the isotope and difference methods of determining N recovery efficiencies. Labeled N was initially concentrated in the stems and leaves, particularly if applied during tuber growth. Over 80% of the assimilated, labeled nitrogen was found in the tubers at the start of plant maturation. These data indicate that a significant improvement in N fertilizer efficiency would result from split N fertilizer applications made according to crop growth needs.  相似文献   

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