J. C. Stark

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.

Response of four potato cultivars to rate and timing of nitrogen fertilizer

The release of three new potato (Solarium tuberosum L.) cultivars, Bannock Russet, Gem Russet, and Summit Russet, with unique plant growth characteristics, necessitates the development of appropriate N fertilizer recommendations. These three new cultivars, along with the standard cultivar, Russet Burbank, were treated with four N rates (0, 100, 200, and 300 kg N ha−1) using two different application timing procedures (“early,” with two-thirds N applied preplant, and “late,” with one-third applied preplant). Measurements included total and U.S. No. 1 yields, petiole NO3-N concentrations, and net returns derived from economic analysis using a processing-based contract. Each of the four cultivars showed a unique response to N application treatments. Bannock Russet achieved maximum yield and net returns with relatively small amounts of N fertilizer. It also showed no response to N application timing and had moderate NO3-N sufficiency concentrations early in the season, that decreased markedly late in the season. Gem Russet N requirement for maximum yield was similar to that of Russet Burbank, but required a higher amount of N for maximum net returns. Gem Russet also showed no response to application timing and had NO3-N sufficiency concentrations similar to or slightly higher than those of Russet Burbank. Summit Russet showed a strong trend for improved N use-efficiency when most of the N was applied early. On the other hand, analysis of net returns revealed a trend for greater profitability for Summit Russet when the majority of N was applied during tuber bulking. Petiole NO3-N sufficiency concentrations for Summit Russet were generally higher than those for the other three cultivars. In comparison with some earlier studies with Russet Burbank, this research suggested lower optimal N rates and petiole NO3-N sufficiency concentrations.ResumenLa liberación de tres nuevos cultivares de papa (Solanum tuberosum L.), Bannock Russet, Gem Russet, y Summit Russet que tienen características únicas de crecimiento, requieren del desarrollo de recomendaciones apropiadas de fertilización nitrogenada. Estos tres nuevos cultivares junto con el cultivar estándar Russet Burbank, fueron tratados con tres dosis (0,100,200 y 300 Kg de N/ha−1) utilizando dos procedimientos de aplicación (“temprano,” con las dos terceras partes de nitrógeno aplicadas antes de la siembra y “tardio,” con la tercera parte de N aplicada antes de la siembra). Se tomó en cuenta el rendimiento total y el rendimiento de U.S. No. 1, concentración de NO3-N en los pecíolos y utilidades netas derivadas del análisis económico neto por contrato de procesamiento. Cada uno de los cuatro cultivares mostró una respuesta especial a los tratamientos de aplicación de N. Bannock Russet alcanzó un rendimiento máximo y utilidad neta con cantidades relativamente pequenas de fertilizante nitrogenado. No mostró respuesta a la época de aplicación de N y tuvo una moderada concentración de NO3-N en los inicios, la misma que fue decreciendo marcadamente hacia finales del período de cultivo. Los requerimientos de N de Gem Russet para un rendimiento máximo fueron similares a los de Russet Burbank pero necesitó una mayor cantidad de N para obtener una utilidad neta máxima. Gem Russet tampoco mostró respuesta a la época de aplicación y presentó suficiente concentratión de NO3-N similar o ligeramente superior a la de Russet Burbank. Summit Russet mostró una fuerte tendencia al uso de N cuando se aplicó con la modalidad de “temprano.rd Por otra parte, el análisis de utilidades netas reveló la tendencia de Summit Russet a una mayor utilidad, cuando la mayor cantidad de N se aplicó en la etapa de desarrollo del cultivo. Las concentraciones adecuadas de NO3-N en el pecíolo fueron generalmente mayores para Summit Russet que para los otros tres cultivares. Comparativamente con algunos estudios anteriores de Russet Burbank, esta investigacion sugiere el empleo de dosis mas bajas de N y de concentraciones adecuadas de NO3-N en el peciolo.

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.CompendioEl manejo del riego y del nitrógeno son dos de los factores más importantes que afectan la eficiencia de la productión y la calidad del ambiente en los sistemas de cultivo de papa. Se condujeron estudios de campo en 1990 y 1991 para determinar los efectos de la interacción de la cantidad de agua aplicada y el momento de aplicación del nitrógeno sobre el rendimiento y la calidad de la papa, y el potencial de lixiviación del nitrógeno. Se aplicó riego por aspersión a aproximadamente 1.0, 1.2 o 1.4 veces la evapotranspiración estimada (ET) a papas Russet Burbank sembradas en un suelo franco-limoso. A continuación del inicio de la tuberización, se aplicaron en el sistema de riego 132 kg N/ha a las subparcelas con tratamiento nitrogenado utilizando ya sea seis aplicaciones semanales de 22 kg N/ha o tres bisemanales de 44 kg N/ha.El riego excesivo redujo la zona radicular y las concentraciones de NO3-N de los peciolos durante considerable parte del periodo de crecimiento de los tubérculos. En 1991 las aplicaciones bisemanales de 44 kg N/ha produjeron en la temporada temprana en las parcelas de 1.2 y 1.4 ET una mayor y más consistente zona radicular, y concentraciones de NO3N, en comparación con las parcelas con aplicaciones semanales de 22 kg N/ha. El peso seco de tubérculo, el peso seco total por planta y la absorción de N por la planta al final de la temporada no fueron afectados por la cantidad de agua de riego ni por el momento de aplicación del N. Si embargo, el riego excesivo redujo el rendimiento de tubérculos U.S. No. 1 y de tubérculos > de 284 g tanto en 1990 como en 1991 así como también el rendimiento total en 1990. Las aplicaciones bisemanales de N produjeron rendimientos más altos de tubérculos U.S. No. 1 que las aplicaciones semanales a todos los niveles de riego. El riego excesivo redujo también al final de la temporada de cultivo los NO3-N remanentes en los 60 cm superiores del suelo. Estos resultados muestran que irrigando con volúmenes óptimos de agua y aplicando el N dividido a intervalos de dos semanas se puede maximizar el rendimiento y la calidad de Russet Burbank al mismo tiempo que se minimizan las pérdidas de NO3-N.

Potato nutrient management in sustainable cropping systems

Sustainable nutrient management involves a set of management practices designed to conserve soil resources, to maintain or enhance productivity, and to help reduce growers’ reliance on chemical fertilizers. Sustainable nutrient management systems will most certainly rely heavily on the use of legume rotation crops and/or organic soil amendments. To realize the full benefit to the crop ecosystem, sustainable nutrient management programs will also likely require longer crop rotations with less frequent potato production. There is considerable research evidence indicating that these systems can maintain or increase productivity while having positive impacts on nutrient supply, soil physical properties, and soil conservation. However, their successful adoption and continued use on a large scale will require resolution of uncertainties related to economic risk associated with inconsistent nutrient availability in alternative nutrient management systems, potential environmental risks associated with excessive P applications in animal manures, and the potential for increased potato pest incidence resulting from manure application.ResumenEl manejo sostenible de nutrientes incluye un conjunto de practicas diseñadas para conservar los recursos del suelo, mantener o intensificar la productividad y ayudar a los agricultores a reducir la dependencia que tienen en los fertilizantes químicos. Los sistemas de manejo sostenible de nutrientes confía mayormente en el uso de leguminosas como cultivos de rotación y/o enmiendas orgánicas del suelo. Para darse cuenta del beneficio del ecosistema del cultivo, el programa de manejo sostenible de nutrientes requerirá de períodos más largos de rotación y de cultivos de papa menos frecuentes. Existe una considerable evidencia de investigación que indica que estos sistemas pueden mantener o incrementar la productividad y al mismo tiempo tienen un impacto positivo sobre el suministro de nutrientes, propiedades físicas del suelo y su conservación. Sin embargo, su completa adopción y uso continuado en gran escala requerirá de resolver ciertas dudas relacionadas con el riesgo económico asociado a la disponibilidad irregular de nutrientes en los sistemas de manejo alternativo, riesgos potenciales del medio ambiente asociados con una excesiva aplicación de fósforo contenido en el estiércol y el potencial para implementar la incidencia de enfermedades como resultado de la aplicación de estiércol.

Optimal allocation of limited water supplies for Russet Burbank potatoes

Water shortages in many potato-producing regions have increased the demand for information on irrigating potatoes with limited water supplies. Field studies were conducted at Aberdeen, Idaho in 1988 and 1989 to determine the optimal allocation of limited water supplies for Russet Burbank potatoes. Irrigation amounts equal to 60 or 80% of estimated seasonal evapotranspiration (ET) were applied using various patterns of water allocation. Irrigation deficits were either partitioned evenly over the entire tuber bulking period, or were imposed during two of three designated growth stages (early, mid or late bulking) corresponding to the periods from 0 to 3, 3 to 6, and 6 to 9 weeks after tuber initiation, respectively. A well-watered, 100% ET check was included for comparison. Total yield reductions were greater when irrigation deficits were imposed during the early-mid and midlate bulking sequences than when they were imposed evenly over the entire tuber bulking period or during the early-late bulking sequence. Results relating U.S. No. 1 yields to seasonal water allocation patterns were similar to those for total yield. However, U.S. No. 1 yield reductions were proportionately greater. Irrigation deficits imposed during the early-mid bulking sequence resulted in the lowest specific gravities and the highest percentages of dark ends.CompendioLa escasez de agua en muchas de las regiones donde se produce papa ha originado que se incremente la demanda por información sobre la irrigación del cultivo en condiciones de un bajo abastecimiento de agua. En 1988 y 1989 se condujeron estudios en Aberdeen, Idaho, para determinar la distribución óptima de cantidades limitadas de agua para papas Russet Burbank. Al irrigar se aplicaron cantidades iguales al 60 u 80% de la evapotranspiración (ET) estimada para la temporada utilizando varios esquemas de distribución de agua. Los déficits de irrigación iguales a 20 o 40% de la ET estimada fueron distribuidos ya sea uniformemente durante todo el periodo de formación de tubérculos o fueron impuestos durante dos de tres etapas consideradas de crecimiento (producción temprana, media o tardía) correspondientes a periodos de 0 a 3, 3 a 6 y 6 a 9 semanas después de iniciada la tuberización, respectivamente. Con fines de comparación, se incluyó un testigo irrigado al 100% de la ET. Las reducciones en el rendimiento total fueron mayores cuando los déficits de irrigación fueron impuestos durante las secuencias de crecimiento o durante la secuencia temprano-tardía de crecimiento. Los resultados al relacionar los rendimientos en U.S. No. 1 con los esquemas de distribución fueron similares a aquellos para el rendimiento total. Sin embargo, las reducciones en el rendimiento de U.S. No. 1 fueron proporcionalmente mayores. Los déficits de irrigacion impuestos durante la secuencia temprano-media de crecimiento resultaron en las gravedades específicas más bajas y los porcentajes más altos de extremos oscuros.

Fertility and management practices to control verticillium wilt of the russet burbank potato

Management practices for the suppression of Verticillium wilt of Russet Burbank potato include sanitation, use of optimum sprinkler-irrigation practices, soil solarization, and an adequate soil fertility program. Among all cultural factors considered, nitrogen (N) deficiency in potato tissue was most commonly associated with the severity of Verticiilium wilt in Russet Burbank potato. Field studies have shown that increased N availability suppresses Verticiilium incidence on cv Russet Burbank while having no effect on cv Norgold Russet. Studies from both greenhouse and field show that the colonization ofV dahliae in potato stem tissue is suppressed in cv Russet Burbank when the availability of Phosphorous (P) is increased to the optimum. Following one season of cropping with Russet Burbank potato, the treatment providing the optimal N availability also suppressed the increases ofV dahliae populations in the soil during the following year of consecutive cropping. Similarly, after two seasons of continuous potato cropping, treatments with optimal P had lower soil populations ofV. dahliae in soil. Results show the suppression of Verticiilium wilt with optimal fertility.Verticiilium wilt [caused by eitherVerticiilium dahliae Kleb, (microsclerotial form) orVerticiilium albo- atrum Reinke and Berthold (dark mycelial form)] is one of the most severe diseases of potato in the United States. Potato yields, tuber size, and specific gravity may be substantially reduced by this disease, depending on severity, time of occurrence, and growing season.In Idaho and other arid growing regions of the United States, Verticiilium wilt is caused byVerticillium dahliae Kleb. Idaho field studies involving cropping practices, soil fumigation treatments, solarization, and Verticillium-resistant potato clones all support the importance ofV dahliae upon potato yield. Data from these studies show that yield losses due toV. dahliae commonly approximate 5 to 12 metric T/ha (5, 6). Table 1 illustrates the effect of several cropping practices upon relativeV dahliae populations in soil with the effects upon both disease severity and potato yield. With continuous cropping of Russet Burbank,V dahliae populations in soil increased, and yields were reduced by 18 to 19 metric Tlha when compared to locations that had been allowed to remain either weed-free and fallow or where corn had been previously cropped. It was estimated thatV dahliae was influencing yield by about 10 to 12 metric Tlha based on a regression analysis of yield as a function ofV dahliae populations in soil. Similarly, whenV dahliae was suppressed by fumigation treatments involving mixtures of dichloropropene and picfume, yields more significantly increased by 6.5 to 12 metric T/ha (5). Although many factors may influence yields, clones with higher Verticillium resistance than Russet Burbank generally out-yield Russet Burbank. Figure 1 demonstrates the effect of solarization (a technique involving the laying of clear plastic on soil for the purpose of elevating soil temperatures to killV dahliae). When Verticillium was controlled in this manner (lo), there was no significant yield difference between the Russet Burbank potato and the highly resistant A68113-4 clone. The A68113-4 clone grown in non-solarized soil out-yielded the Russet Burbank in non-solarized soil by 31 percent while the solarization treatment significantly increased yield for the Russet Burbank and A68113-4 clones by 46 and 18 percent, respectively. These yield responses were observed in a field where inoculum levels ofV dahliae were relatively low (2.10 cfulgrn of soil). With these losses, the need to develop control procedures is great and to achieve this control the need also exists to accurately evaluate the effect of treatments uponV dahliae. Our Idaho studies have routinely utilized such a procedure (9) in combination with comparisons of both disease severity and yield.

Biochemical characteristics of potato clones differing in blackspot susceptibility

The relationships between enzymatic discoloration and selected biochemical characteristics of tubers from nine clones were determined in an attempt to explain varietal differences in blackspot susceptibility. These nine clones represent a wide range of blackspot susceptibility as determined by two discoloration indices after abrasive peeling. Enzymatic discoloration for combined data from the 1983 and 1984 growing seasons was highly correlated with total phenol (r=0.89) and tyrosine (r=0.85) concentrations. Conversely, discoloration was negatively correlated with soluble protein in 1983 (r=-0.78) and 1984 (r=-0.77). Polyphenoloxidase (PPO) activities, apparent Michaelis constants and maximum velocity values, from crude and partially purified enzyme preparations, were not significantly correlated with enzymatic discoloration. Varietal susceptibility to enzymatic discoloration appears to be related to concentrations of endogenous phenolic substrates of PPO, rather than to differences in the quantity or properties of the PPO enzyme.ResumenLa relación entre la decoloración enzimática y las características bioquimicas seleccionadas de tubérculos de nueve clones de papa fue determinada en un intento por explicar las diferencias varietales en la susceptibilidad a la mancha negra. Estos nueve clones representan un amplio rango de susceptibilidad a la mancha negra de acuerdo con dos indices de decoloración después de raspar la piel. La decoloración enzimática para información combinada de los cultivos de 1983 y 1984 estuvo altamente correlacionada con las concentraciones finales de phenol total (r=0,89) y de tyrosina (r=0,85). Recíprocamente, la decoloración fue negativamente correlacionada con la proteína soluble en 1983 (r=−0,78), y 1984 (r=−0,77). Las actividades de la polyphenoloxidase (PPO), las constantes aparentes de Michaelis, y los valores máximos de la velocidad, de las preparaciones de enzima cruda y parcialmente purificada, no estuvieron significativamente correlacionadas con la decoloración enzimática. La susceptibilidad varietal a la decoloración enzimática parece estar correlacionada a las concentraciones de los substratos fenólicos endógenos de PPO más que a las diferencias en la cantidad o propiedades de la enzima PPO.

Interactive effects of nitrogen and phosphorus on Verticillium wilt of Russet Burbank potato.

A three-year field study was conducted during 1984–1986 to determine the interactive effects of nitrogen and phosphorus fertilization on Verticillium wilt, and yield and quality of continuously-cropped Russet Burbank potato. The experiment was conducted on a calcareous, silt loam soil with low initial levels of NO3-N (0.9 mg/kg), P (3.5 mg/kg), andVerticillium dahliae (9 cfu/g of soil). The experimental design consisted of a factorial combination of three N treatments (unfertilized check, preplant N or split N) and three P treatments (0,120, or 240 kg P/ha) applied to the same plots during the three-year study. Nitrogen was applied at 0 or 300 kg N/ha in 1984 and 0 or 240 kg N/ha in 1985 and 1986. By the spring of 1986, soil P concentrations for the 0,120, and 240 kg P/ha treatments had increased to 7, 25, and 50 mg/kg and no additional P was applied.In addition to suppressing Verticillium wilt by as much as 95%, N & P treatments also reduced the rate of increase of soilborne inoculum ofV. dahliae. After one season of cropping, the N treatment providing the most efficient N fertilization (300 kg N/ha, split-application) resulted in significantly (p=0.01) lowerV. dahliae counts in soil than the other N treatments. After two seasons of continuous cropping, applying 120 to 240 kg P/ha produced lower populations ofV. dahliae in soil compared to the treatment with no added P. Generally, as N and P treatments approached the highest levels, both wilt incidence andV. dahliae colonization values were reduced.There was a progressive reduction in total yield in nearly all treatments during each year of continuous cropping. Reduction of yield and increased Verticillium wilt incidence was generally greater with N or P deficient plants than with optimally fertilized plants. The highest total and U.S. No. 1 yields and least Verticillium wilt were obtained each year by applying split N and 240 kg P/ha. Results show that optimal N and P can minimize both Verticillium wilt and yield losses that normally occur with intensive potato cropping.

COMPARISON OF SITE-SPECIFIC AND CONVENTIONAL UNIFORM IRRIGATION MANAGEMENT FOR POTATOES

Site-Specific Irrigation Management (SSIM) can be defined as irrigation management (depth, timing) based on crop need to defined sub-areas of a field referred to as management zones. Implementation of SSIM will require additional irrigation system hardware, labor, and information on soil and/or plant water status in each management zone. Costs associated with these additional requirements will need to be offset by increased receipts from improved crop yield and quality in order for the technology to be adopted by producers. The potential for SSIM to increase crop yield, quality, and economic return has not been evaluated in field studies. Crops such as potatoes, for which yield and quality are highly sensitive to soil water availability, are most likely to show an economic benefit from site-specific irrigation management. A two-year field study was conducted to evaluate the potential for SSIM to increase yield and quality of potatoes relative to Conventional Uniform Irrigation Management (CUIM). Near real-time soil water content was used to schedule irrigations under both irrigation management treatments. Field average water application was nearly the same for the irrigation management treatments, 503 mm (19.8 in.) in 2001 and 445 mm (17.5 in.) in 2002. In both study years, tuber yield distributions trended 4% greater under site-specific irrigation management but were not significantly different (p < 0.05). Total tuber yield per unit of water applied from irrigation and precipitation was 4% greater in 2001 and 6% greater in 2002 under SSIM. Based on a local tuber quality adjusted potato processing contract price structure, the trend in gross income averaged across the field site was

Computer control system for spatially varied water and chemical application studies with continuous-move irrigation systems

159/ha (