Yield, water use efficiency and nitrogen uptake in potato: influence of drought stress

Summary A lysimeter experiment was performed to study the optimal allocation of limited water supply in potatoes. Irrigation regimes equal to 40, 60 and 80% of maximum evapotranspiration (ET) were evenly applied over the crop cycle. Other treatments involved withholding 80 mm of irrigation, based on ET, beginning at each of three designated growth stages (tuber initiation, early and late tuber growth). An irrigated control treatment, restoring the entire ET, was included for comparison. Continuous drought stress reduced photosynthesis as irrigation volumes were reduced. Plant biomass and tuber yield decreased almost proportionally to water consumption, so that WUE was roughly constant. N uptake was highest in the control and in 80% ET treatment. Withholding water during tuberisation severely hindered plant physiological processes and penalized tuber yield. Reductions in photosynthesis, total biomass and yield were the greatest when drought was imposed during tuber initiation. The earliest stress resulted in the lowest WUE and N uptake. A new crop water stress index (SI) was proposed, which combines atmospheric demand for water and canopy temperature.     

Influence of irrigation and nitrogen management on potato yield and quality

The effects of irrigation, water and nitrogen management on yield and quality of the Russet Burbank cultivar are discussed relevant to developmental stages of growth. Recent research on the interactions of irrigation and nitrogen management on total and U.S. No. 1 yields and specific gravity are presented. Total and U.S. No. 1 yields decline with increasing soil moisture stress. Yield of U.S. No. 1 potatoes is particularly sensitive to short periods of irrigation deficit during tuber initiation. Total yield appears most sensitive to short periods of irrigation deficit during tuber bulking. Allocation of longer term irrigation deficits during years of limited water supply should be either a) avoided during mid-season tuber bulking, or b) uniformly distributed over the entire tuber bulking growth period. Yield increases with higher total available soil nitrogen under deficit irrigation, but the yield response diminishes as the amount of total seasonal water decreases. The influence of irrigation and nitrogen availability is also discussed for specific gravity and tuber maturity. Seasonal (split) nitrogen management is proposed as a method to improve yield, quality and nitrogen fertilizer use efficiency of indeterminant cultivars.     

Potato Cultivar Response to Seasonal Drought Patterns

The ability to minimize potato yield and quality losses due to drought can be greatly improved by understanding the relative responses of different cultivars to seasonal variations in water supply. To address this need, we initiated a 2 year field experiment to determine the responses of the six potato cultivars to different seasonal drought patterns, including 1) full season irrigation at 100 % ET, 2) irrigation at 100 % ET terminated during late bulking , 3) full season irrigation at 70 % ET , 4) irrigation at 70 % ET terminated during late bulking , and 5) a gradual reduction in irrigation from 100 % ET during tuber initiation through early bulking, to 70 % ET during mid-bulking, and 50 % ET through late bulking. GemStar Russet and Ranger Russet, two medium-late maturing cultivars, generally produced the highest yields across the range of drought treatments, but both were fairly sensitive to changes in drought severity. Alturas, a late maturing cultivar, produced relatively high yields with full irrigation, but exhibited the greatest sensitivity to increasing drought severity, particularly when severe late-season water deficits were imposed. Yields for the early maturing cultivar Russet Norkotah were relatively low overall, but it was the least sensitive to changes in drought severity, particularly when late season drought was imposed. Russet Burbank produced comparatively high total yields across the range of drought treatments, but U.S. No. 1 yields were substantially reduced by each seasonal drought pattern. However, it was less sensitive to changes in drought severity than GemStar Russet, Ranger Russet and Alturas. Total and U.S. No. 1 yields for Summit Russet were low for each drought treatment and it exhibited intermediate sensitivity to changes in drought severity. GemStar Russet had the highest water use efficiency based on U.S. No. 1 yield.     

Potato response to split nitrogen timing with varying amounts of excessive irrigation

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.     

Yield-evapotranspiration relationships and seasonal crop coefficients for frequently irrigated potatoes

‘Russet Burbank’ potatoes (Solarium tuberosum L.) were subjected to various levels of water application during the growing season. Water applied, rainfall, and soil water changes were measured at weekly intervals. Tuber yield and quality increased as water consumption increased from 300 mm to 650 mm. Evapotranspiration (ET) increased rapidly from plant emergence until early tuber bulking and declined gradually as plants matured. Comparing ET with pan evaporation provided coefficients (K) which changed in response to crop growth stages. K increased from 0.3 at emergence to over 0.8 during maximum leaf area and declined with crop maturity. The relationship between K and crop growth stage can be used with confidence in scheduling irrigation of potatoes in north central Oregon.     

The effect of timed water stress on quality,total solids and reducing sugar content of potatoes

Potato (Solanum tuberosum L.) solids and reducing sugars were examined before, just after, and two weeks after transient water stress to gain an understanding of tuber changes that occur directly associated with water stress. Russet Burbank and A082260-8 potatoes were grown on Owyhee silt loam at the Malheur Experiment Station, Ontario, Oregon. Potatoes were subjected to a single episode of transient water stress by omitting furrow irrigation in either late June, July, or in early August of 1988 and 1989 to examine variety differences in the short term effects of water stress on changes in solids and reducing sugars in tuber stem ends. Irrigation was managed to maintain soil water potential above -65 kPa at 20 cm depth during tuber initiation through bulking except during transient stress when the soil water potential reached -82 to -110 kPa. Tuber samples were taken from plots and minimally stressed check treatments before stress, at the peak of stress, two weeks after the transient stress period, and after harvest. Tubers were sectioned longitudinally and the percent solids and reducing sugars were determined for samples from the tuber stem end, center, and apical end. Longitudinal tuber strips were fried after harvest to determine fry color. Tuber stem-end fry color did not darken in A082260-8 potatoes subjected to water stress. The line A082260-8 had higher stem-end solids and lower stem-end reducing sugars than Russet Burbank. Neither variety responded to transient water stress or recovery from transient stress with an immediate increase in reducing sugars in any tuber part. Reducing sugars were elevated in harvested tubers, particularly in the stem-ends of Russet Burbank potatoes subjected to water stress. Increases in tuber reducing sugars related to transient water stress were not found during the stress period or immediately after stress, but were present in harvested tubers.     

Irrigation and soil temperature effects on Russet Burbank quality

Potato growers in the Pacific Northwest suffer large economic losses in seasons with above normal temperatures, due to excess reducing sugars in tubers, which cause dark-end French fries. Our objective was to study irrigation management effects on potato quality, particularly the factors causing dark-end French fries or sugar-end syndrome. Solid-set sprinkler irrigated plots were established on potatoes at Kimberly, Idaho during the 1987, 1988 and 1989 irrigation seasons, and at Parma, Idaho in 1987 and 1988. Irrigation treatments were high and low frequency (3/week and I/week) and two or three water application amounts referenced to estimated evapotranspiration (ET, ET+20%, and ET-20%). Neither frequency nor amount significantly affected yields. Irrigation frequency had more influence on potato quality than application amount. More frequent irrigation produced slightly higher quality tubers and lower incidence of dark-ends when fried. Soil temperature was inversely related to tuber grade quality and directly related to percentage of sugar-end tubers. Soil temperature was about 0.5 C lower under the high frequency than under the low frequency irrigation regime. On these silt loam soils, allowing available soil water to decline to 50 percent had no adverse affect on yield or quality.     

Tuber growth and biomass partitioning of two potato cultivars grown under different n fertilization rates with and without irrigation

Nitrogen and water deficiencies are known to affect potato yield, but much less is known of their effect on tuber growth and biomass partitioning. The objective of this on-farm study conducted at two sites in each of three years, 1995 to 1997, was to determine the effects of supplemental irrigation and N fertilization rates on tuber growth and biomass partitioning of the cultivars Shepody and Russet Burbank. The N fertilization rates were 0,100, and 250 kg N ha^-1in 1995, and 0, 50,100, and 250 kg N ha_?1 in 1996 and 1997. The highest bulking rate observed in our study (7.3 g fresh tubers m^-2 °C^-1) can be considered near the potential bulking rate in New Brunswick. The water deficit in the absence of supplemental irrigation reduced this potential bulking rate by as much as 40%, but this reduction was much less at five of six sites and negligible at two of six sites. Nitrogen deficiency reduced the bulking rate at two of six sites. This negative effect of N deficiency on bulking rate was greater with irrigation than without irrigation at two of six sites; the tuber bulking rate with irrigation was reduced by as much as 50% with no N applied at one site. Shepody had a greater bulking rate than Russet Burbank. The tuber bulking of Russet Burbank, however, started earlier and lasted longer than that of Shepody. Water and N deficiencies increased biomass partitioning to tubers and large roots. Shepody partitioned a greater proportion of its biomass to large roots and had a greater root biomass than Russet Burbank. Our results demonstrate the ability of potatoes to modify biomass partitioning when grown under water and/or N stresses. As a result of this compensation, the reduction in tuber yield due to limited N and water stresses is minimized.     

Dry matter accumulation in potato clones under seasonal high temperature conditions in Pakistan

The effects of seasonal high temperatures on potatoes were investigated under field conditions near Peshawar, Pakistan. Five potato clones (A79196-1, Desiree, DTO-28, LT-1, Russet Burbank) were grown during the spring season at two locations. Canopy development, vine dry weight and tuber dry weight were determined at 13-day intervals, starting 68 days after planting (DAP). Tuber yield was higher in heat tolerant clones compared to heat susceptible clones. Location significantly affected tuber dry weights. Tuber dry weights of Russet Burbank were consistently lower than those of DTO-28. Ground canopy cover of DTO-28 occurred earlier and reached maximum at 75 DAP, compared to 90 DAP for Desiree. DTO-28, because of its high tuber yield under cool as well as hot temperatures, and its relatively early bulking, should be a promising clone for a short duration crop in hotter regions.     

Cultivar and seedpiece spacing effects on potato competitiveness with weeds

Field studies were conducted in 1991 and 1992 to evaluate the effects of cultivar, row spacing, and within-row spacing on potato yield and quality under weedy and weed-free conditions. Cultivars tested were Russet Burbank, an indeterminate, large-vined cultivar, and Frontier Russet, a determinate, small-vined cultivar. The two cultivars were grown under weedy and weedfree conditions with either 76 or 91 cm row spacings in factorial combination with either 15, 25, or 35 cm within-row spacings. The major competitive weeds were redroot pigweed, common lambsquarter and hairy nightshade. The weedy plots consistently produced less vine and tuber biomass and less total and U.S. No. 1 tuber yield than the weed-free plots. The time of weed emergence strongly affected potato competitiveness with weeds. In 1991, weeds emerged after potatoes, giving the crop some competitive advantage. In 1992, weeds emerged before the potatoes, resulting in heavy competition and large decreases in vine and tuber production for both cultivars. Reductions in U.S. No. 1 tuber yield were proportionally greater than the reductions in total yield. Weedy plots in 1991 and 1992 produced 25% and 68% less total yield and 43% and 92% less U.S. No. 1 yield, respectively, than weed-free plots. Russet Burbank was more competitive with weeds than Frontier Russet. Frontier Russet suffered substantial losses in productivity due to the presence of weeds, even under moderate weed pressure in 1991. Decreasing the row width from 91 to 76 cm did not provide a competitive advantage for potatoes as measured by vine or tuber biomass, or tuber yield. Decreasing within-row spacing under weedy conditions provided some competitive advantage and resulted in higher vine and tuber biomass and greater total tuber yield. The closer within-row spacing resulted in a substantial decrease in U.S. No. 1 yield with Russet Burbank but a slight increase with Frontier Russet. There were several significant interactions involving cultivar, weed level, and within-row spacing. These were due, in part, to each cultivar’s unique response to inter-and intraspecies competition. Cultivar had a greater influence on competitiveness than any plant spatial arrangement.     

Responses of three early potato cultivars to subsoiling and irrigation regime on a sandy soil

A compact subsoil restricts rooting and reduces the volume of soil from which plant roots can obtain water and nutrients. A reduced water supply may result in severe plant water stress between irrigations. A study was conducted on a sandy soil to evaluate the responses of three early potato cultivars (Norgold Russet, HiLite Russet, and Russet Norkotah) to subsoiling to loosen a compact subsoil and to four irrigation regimes. Differences among cultivar responses to irrigation and subsoiling treatments were minor. All performed best with daily irrigation to replace évapotranspiration (ET) and poorest when irrigation was interrupted during tuber bulking. With daily irrigation to replace ET, subsoiling had little benefit, but with inadequate irrigation, subsoiling improved yield and quality of tubers compared to not subsoiling. Averaged over all treatments, HiLite was the lowest yielding cultivar and had the least U.S. No. 1 and the most undersize tubers. Norkotah had the most U.S. No. 1 and the fewest undersize tubers.     

Effects of drip irrigation regimes on potato tuber yield and quality under plastic mulch in arid Northwestern China

Field experiments were conducted to study the effects of drip irrigation regimes on potato (Solanum tuberosum L.) growth, tuber yield and quality, and water use efficiency (WUE) when grown under plastic mulch in an arid area of Northwestern China in 2008, 2009 and 2010. The 2008 experiment consisted of a drip irrigation check without plastic mulch and four different drip irrigation frequency treatments with plastic mulch: once every day, once every 2 days, once every 4 days, and once every 8 days. In 2009 and 2010 the drip check treatment without mulch was irrigated at −25 kPa soil matric potential (SMP) during three potato development stages and four different SMP drip irrigation strategies were compared during the potato development stages (using plastic mulch): S1 (−25 kPa SMP during the three development stages), S2 (−25 kPa SMP during tuber initiation and bulking and −35 kPa SMP during maturation), S3 (−25 kPa SMP during tuber initiation and maturation and −35 kPa SMP during bulking), S4 (−35 kPa SMP during the three development stages). Plastic mulch negatively affected tuber yield, WUE, and tuber quality. In the presence of plastic mulch, tuber yield, specific gravity, starch content, and vitamin C content seemed to be enhanced as the irrigation frequency increased, although the differences were not statistically significant. Irrigation frequency did not affect WUE for potato grown under plastic mulch. Analysis of plant height, tuber yield and WUE showed that a drip irrigation threshold of −35 kPa SMP led to obvious water stress for potato growth in this arid area. Under plastic mulch in 2010, S2 was the optimum drip irrigation regime because of the significantly higher yield than S3 and S4, the highest WUE and significantly firmer tubers than any of the other irrigation regimes tested.     

The effect of short periods of shading at different stages of growth on the development of tuber number and yield

Summary Shading potato plants at the beginning of tuber initiation for a period of 12 days reduced the rate of tuber formation and growth; but after the shades were removed tuber formation continued to give more tubers and the shaded plants eventually produced 30% more tubers than the unshaded, with similar yield. Shading for 12 days during the early stages of rapid tuber bulking had no effect on tuber number or survival, though bulking rate was temporarily reduced, leading to a reduction in final yield. These number results indicate that tuber number can be influenced by the weather during the period of tuber initiation.     

Evaluation of on-farm irrigation scheduling methods for potatoes

The neutron probe, infrared thermometry and crop water stress index (CWSI), and a computer-assisted irrigation scheduling method were evaluated in terms of their effect on tuber yield, tuber quality, and water use. The experiment was conducted during 1990 and 1991 near Othello, central Washington, using Russet Burbank potatoes grown in a silt loam soil. Irrigation treatments did not commence until after tuber initiation. In general, no differences in total number of tubers and total tuber yield resulted from the different scheduling methods. However, the canopy temperature method showed reduction in the yield of number one tubers in 1990. The least total irrigation water was applied during the growing season with the neutron probe method. Using CWSI values above 0.5 to 1.0 (scale 0 to 10) for two consecutive days as a threshold to schedule irrigations appeared to be adequate for potatoes grown in silt loam soils. However, shortcomings of infrared thermometry suggested that this method may not be practical for scheduling irrigation of potatoes.     

Effect of declining or interrupted irrigation on yield and quality of three potato cultivars grown on sandy soil

Many potatoes in the Northwest are grown on sandy soils with sprinkler irrigation. The low water holding capacity and restricted rooting often associated with coarse-textured soils create conditions where water stress injury is likely. Temporary water shortage due to irrigation system failure is a hazard on these soils. The Russet Burbank cultivar is often severely injured by such water stress. It is not known how the cultivars Nooksack and Lemhi respond to these conditions. A study was conducted to compare the responses of Russet Burbank, Nooksack, and Lemhi cultivars to interruptions in irrigation during tuber initiation or during bulking, and to gradually increasing water stress from declining water application rates during the last 8 to 10 weeks of the growing season. In most categories evaluated, Russet Burbank was most injured by water stress, especially in percent U.S. No. 1 tubers. Much of the decrease in U.S. No. 1 tubers was due to small size. Nooksack generally was the least affected by water stress while Lemhi was affected slightly more than Nooksack. Both Nooksack and Lemhi withstood periods of water stress and produced satisfactory yields and grades of tubers while Russet Burbank did not produce profitable levels of marketable tubers.     

Validation of a simple potato growth model in the North Central United States

A simple potato growth model was validated in 1985 and 1986 at two dryland sites, Grand Forks, ND and Rosemount, MN, and one irrigated site, Hancock, WI. At each site, Russet Burbank potatoes were grown to maximize yield. Leaf area index and leaf, stem, root, and tuber biomass data were collected from replicated experiments every two weeks. Soil matric potentials, minimum and maximum temperatures, and solar radiation also were measured. Among sites, crop development rates and solar radiation receipts were similar, but final tuber yields differed by as much as 35 Mg/ha. Model predictions of leaf, stem, and tuber dry weights were similar to observed data both in terms of maximum values attained and seasonal development except for the experiment in Grand Forks in 1986 where the model over-estimated final tuber yield by 23 Mg/ha (115%). Soil aeration or salinity, factors not currently modeled, may account for this discrepancy. Modeled yield responses to defoliation were compared with field data from one of the experimental locations. At levels of defoliation below fifty percent, proportional yield reductions were similar between observed and modeled crops.     

几个马铃薯品种产量及品质形成的差异

以3个马铃薯品种为供试材料,在块茎增长期进行分期取样,对不同品种的产量和品质形成状况进行比较,以摸清不同品种的块茎形成特性,为特定品种配套适宜栽培技术的实施提供参考。结果表明：供试3个品种的单株产量存在显著差异,延薯4号的产量最高,薯块膨大早,商品薯率高;东农309的产量其次,薯块膨大较早,商品薯率较高;克新13号的产量最低,薯块膨大偏晚,商品薯率中等;但3个品种的单株结薯数量和干物质含量相近,均为结薯数量适中、干物质含量中等的中晚熟鲜食型品种。在生产上应根据品种特性配套栽培技术,以保证各品种获得较好的产量和品质。     

Root System Development Including Root Branching in Cuttings of Cassava with Reference to Shoot Growth and Tuber Bulking

Summary

In spite of the important role it plays for water and nutrient acquisition, information on the root system development in cassava (Manihot esculenta Grantz) is limited. To examine the root length and branching pattern with reference to shoot growth and tuber bulking, we grew cassava plants in containers under natural climatic conditions in the southern end of Sumatra Island, Indonesia. One 20-cm length cutting of cassava (cv. Ardira IV) was planted in either a plastic bucket or a wooden box. The containers, which were filled with heavy clay soil, had different sizes depending on the growing period. At 30, 60, 100, 140, 180, and 270 days after planting (DAP), both the shoot and roots were sampled for quantitative analysis. The dry weight of both shoot and roots increased rapidly with the leaf area. The axile root number, however, decreased from 60 to 140 DAP as a result of the abscission of roots emerging from the basal part of the cutting during tuber bulking. The total root length reached its maximum at 60 DAP and significantly decreased thereafter because of decay and decomposition during tuber bulking. On the other hand, the root branching either increased the branching order or retained it, as determined from a topological point of view. The root branching during the later growing period compensated for the decrease in total root length and contributed to maintain a sufficient root surface area. The surviving roots with a well-developed branching pattern could absorb water and nutrients essential for tuber bulking.     

Field performance of potato (Solanum spp.) cuttings in the warm tropics: Influence of planting system,hilling, density and pruning

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.     

Influence of slitted polyethylene mulch,nitrogen rates,and trickle irrigation on potatoes

In 1974, potatoes(Solanum tuberosum L.) were grown on unmulched, clear, and black slitted polyethylene. Production and tuber specific gravity of the potatoes were determined at four nitrogen rates (0, 75, 150 and 225 lb/A) and with two varieties (Superior and Katahdin). In 1975, potatoes were grown on unmulched and clear slitted polyethylene with and without trickle irrigation. Nitrogen increased marketable yields up to 150 lb/A on the unmulched potatoes. Irrigation increased the marketable yields of potatoes on both unmulched and mulched plots. However, no advantage was found in marketable yields, specific gravities or tuber sizes of the potatoes grown on either clear or black slitted polyethylene mulch over conventional unmulched soil for the ‘Superior’ or ‘Katahdin’ varieties.