D. T. Westermann

Nutritional requirements of potatoes

Plant nutrition is the practice of providing to the plant the right nutrient, in the right amount, in the right place, at the right time. This paper gives an overview of the roles that each of the 16 essential nutrients have in plant nutrition, their relative mobility as related to deficiency symptom expression, and what is generally known about nutrient responses to field applications on potatoes (Solanum tuberosum L.) in the USA and Canada. Maintaining high crop yields with minimum nutrient losses to the environment is and will continue to be a significant challenge to the potato producer. Additional nutritional research efforts in genetically modified plants, precision agriculture, food quality and safety, fertilizer impurities, and other management concerns should significantly help the producer in this effort.ResumenLa nutrición vegetal consiste en proporcionar a la planta el nutriente correcto, la cantidad correcta, el lugar correcto y el momento correcto. Este artículo da una visión general de los roles que tiene cada uno de los 16 nutrientes esenciales en la planta, su movilidad en relación con la expresión de los síntomas de deficiencia y lo que generalmente se conoce sobre las respuestas de la aplicación en papa (Solanum tuberosum L.) en el campo, en EUA y Canadá. El hecho de mantener rendimientos altos con pérdida mínima de nutrientes en el suelo es y continuará siendo un desafío significativo para el productor de papa. Cualquier esfuerzo de investigación que se haga sobre nutrición adicional en plantas genéticamente modificadas, agricultura de precisión, calidad alimentaria y seguridad, impurezas de los fertilizantes y otros aspectos de manejo deben ayudar significativamente al productor.

NITROGEN FERTILIZER EFFICIENCIES ON POTATOES

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.CompendioPara una aplicación exitosa del fertilizante nitrogenado se debe conocer la eficacia del mismo, de acuerdo con las necesidades de crecimiento del cultivo. El objectivo de este estudio fue determinar la recuperatión, división, y transporte del fertilizante nitrogenado aplicado en diferentes periodos en la productión de papas. Se fertilizaron papas del cultivar Russet Burbank con sulfato de amonio carente de15N, antes de la siembra, y con úrea conteniendo K15NO3 durante el crecimiento inicial y final de los tuberculos en 1978 o con (15NH2)2CO en 1980. Todas las aplicaciones de N incrementaron los rendimientos en tubérculos por encima de aquellos en los tratamientos testigo. La eficacia en la recuperación del N fue 60% para la aplicación de N anterior a la siembra, y más de 80% y cerca de 60% para las aplicaciones de N durante el crecimiento de los tubérculos, en 1978 y 1980, respectivamente. Se considerró que la eficacia más baja en 1980 fue causada por una deficiencia de P al final de la temporada. Se encontró buena relación entre el método del isótopo y el de las diferencias, para la determinación de la eficacia en la recuperación del N. El N marcado se concentrró inicialmente en los tallos y hojas, principalmente cuando fue aplicado durante el crecimiento del tubérculo. Se econtró en los tubérculos más de 80% del nitrógeno marcado asimilado al inicio de la maduración de las plantas. Estos datos indican que una mejora significativa tendría lugar en la eficacia del fertilizante al dividir las aplicaciones del fertilizante nitrogenado efectuadas de acuerdo con las necesidades de crecimiento del cultivo.

NITROGEN AND POTASSIUM FERTILIZATION OF POTATOES: YIELD AND SPECIFIC GRAVITY'

Potassium and N fertilization is often required for maximum potato (Solanum tuberosum L.) production. Nitrogen, K, and K-sources (KCl, K2SO4 are known to affect yield and quality of potatoes but N and K interactions as affected by K-source have not been defined. This study evaluated the N*K and K-source interactions on Russet Burbank tuber yields and specific gravity (SG) in two irrigated field experiments. Nitrogen rates of 0, 112, 224 or 336 kg ha-1 were combined with selected K rates of 0,112, 224 or 448 kg ha-1 as either KC1 or K2SO4 in an incomplete factorial. A multiple linear regression model was fit to the data and used to predict yield and SG for a complete factorial for each K-source. Both N and K applications increased yields independent of K-source. Nitrogen decreased yields at the 336 kg ha-1 rate. Potassium increased yields up to 448 kg K ha-1. Both K-sources decreased SG a similar amount with N application; without N, KC1 decreased SG but K2SO4 did not. Nitrogen also decreased SG. Petiole NO3-N and K concentrations were positively related to yields and negatively to specific gravities. The petiole K concentration 100 days after planting should be above 4.5 for highest tuber yields. The N*K*K-source interaction was important for yields at low available N and for SG at adequate N availabilities. This study showed that N or K fertilizers can be applied according to their respective soil test concentration and the crop’s requirement, generally without consideration of K-source.CompendioPara una producción máxima de papa (Solarium tuberosum L.) se requiere frecuentemente de la fertilización nitrogenada y potásica. Se sabe que el nitrógeno (N), el potasio (K) y las fuentes de potasio (KCL, K2SO4) afectan el rendimiento y la calidad de la papa, pero las interacciones del N y el K en relation a la fuente de K no han sido definidas. Este estudio evaluó en dos experimentas de campo bajo irrigación las interacciones de N*K con la fuente de K sobre los rendimientos en tubérculos y la gravedad específica (GE) de Russet Burbank. Dosis de nitrógeno de 0,112, 224 o 336 kg ha-1 se combinaron con dosis seleccionadas de Kde 0,112, 224 o 448 kg ha-1 como KCL o como K2S4 en un factorial incompleto. Un modelo de regresión lineal multiple fue adaptado a los datos y utilizado para pronosticar el rendimiento y la GE por un factorial complete para cada fuente de K. Tanto las aplicaciones de N como las de K incrementaron los rendimientos independientemente de la fuente de K. La dosis de 336 kg ha-1 de nitrógeno disminuyó los rendimientos. El potasio, hasta 448 kg ha-1, aumentó los rendimientos. Ambas fuentes de K disminuyeron la GE en cantidades similares con la aplicación de N; sin N, el KCL disminuyó la GE, lo que no hizo el K2PO4. El N también disminuyó la GE. Las concentraciones de NO3-N y de K en el peciolo estuvieron positivamente relacionadas a los rendimientos, y negativamente a las gravedads específicas. Las concentraciones de potasio en el peciolo, 100 días después de la siembra, debieron ser superiores a 4.5 para los más altos rendimientos en tubérculos. La interacción N* K* fuente de K fue importante para rendimientos a bajo contenido disponible de N y para GE a disponibilidades de N adecuadas. Este estudio muestra que los fertilizantes nitrogenados y potásicos pueden ser aplicados de acuerdo a su concentración en el suelo y los requerimientos del cultivo, sin considerar, generalmente, la fuente de potasio.

Nitrogen and potassium fertilization of potatoes: Sugars and starch

Considerable evidence exists that both N and K influence potato (Solanum tuberosum L.) yields and quality. The impact of nutrients on tuber quality parameters under field conditions should be identified so optimum management practices can be utilized. We evaluated the N and K fertilization by K-sources effects on concentrations of nutrients, reducing sugars, sucrose and starch in the stem and apical tuber ends from two irrigated field experiments with the Russet Burbank cultivar. Nitrogen rates of 0,112, 224 or 336 kg ha−1 were combined with selected K rates of 0, 112, 224 or 448 kg ha−1 as either KCl or K2SO4 arranged as an incomplete factorial. A multiple linear regression model was fit to the data and used to predict the response surface for a complete factorial for each K-source. Nitrogen applications increased or decreased reducing sugars in the apical and stem ends, respectively. Potassium decreased reducing sugars in both tuber ends. Sucrose was higher in the apical end than in the stem end but was not appreciably affected by fertilizer treatment. Nitrogen and potassium applications reduced dry matter and starch concentrations in both tuber ends. Potassium had a smaller effect on the apical end when starch was expressed on a dry weight basis, indicating that increased water content was a factor in the K effect. Both N and K concentrations in the tuber ends were negatively related to starch concentrations, but the relationship was different for the apical and stem ends. Tuber Cl concentration indirectly affected starch concentrations in the stem end when KCL was applied. The K fertilization effect on specific gravity depended upon the K concentration in the harvested tuber and was independent of K fertilizer source. These data illustrate the effects of preplant N and K fertilization rates on final tuber quality parameters. Additional studies are needed to further define the effects of nutrient concentrations at different plant growth stages.CompendioExiste considerable evidencia que tanto el N como el K influencian los rendimientos y calidad de la papa (Solanum tuberosum L.). El impacto de los nutrientes sobre los parámetros de calidad de la papa, bajo condiciones de campo, debe ser identificado de modo que pueden utilizarse prácticas óptimas de manejo. Se evaluó la fertilización con N y K por los efectos de las fuentes de K sobre la concentración de nutrientes, los azúcares reductores, sucrosa y almidón en los extremos apical y terminal de tubérculos de dos experimentos de campo bajo irrigación, con el cultivar Russet Burbank. Se combinaron dosis de 0,112, 224, o 336 kg ha−1 de N, con dosis seleccionadas de Kde 0,112,224 o 448 kg ha−1, sea como KC1 o como K2SO4, dispuestas como un factorial incompleto. Se dispuso la información convenientemente en un modelo de regresión linear múltiple y se le utilizó para pronosticar la superficie de respuesta para un factorial completo para cada fuente de K. Las aplicaciones de N incrementaron o disminuyeron los azúcares reductores en los extremos apical y terminal, respectivamente. El K redujo los azúcares reductores en ambos extremos del tubérculo. La sucrosa fue más alta en el extremo apical que en el terminal, pero no fue apreciablemente afectada por el tratamiento con fertilizantes. Las aplicaciones de N y K redujeron las concentraciones de materia seca y almidón en ambos extremos del tubérculo. El K tuvo un efecto menor sobre el extremo apical cuando se expresó el almidón en base al peso seco, indicando que el incremento de contenido de agua era un factor en el efecto del K. Tanto las concentraciones del N como las del K, en los extremos del tubérculo, estuvieron relacionadas negativamente a las concentraciones de almidón, pero la relación fue diferente para los extremos apical y terminal. Cuando se aplicó KCl las concentraciones de Cl en el tubérculo afectaron indirectamente las concentraciones de almidón en el extremo terminal. El efecto de la fertilización con K sobre la gravedad específica dependió de la concentración de K en el tubérculo cosechado y fue independiente de la fuente de fertilizante potásico. Estos datos ilustran los efectos de las dosis de fertilización con N y K, aplicadas previamente al sembrío, sobre los parámetros de calidad final de los tubérculos. Se requieren estudios adicionales para définir aún más los efectos de las concentraciones de nutrients a diferentes estados de crecimiento de las plantas.

Measurement of atmospheric ammonia, methane, and nitrous oxide at a concentrated dairy production facility in Southern Idaho using open-path FTIR spectrometry

The number of dairy cows in Idaho has increased by approximately 80% in the last decade, with the majority of these facilities located in southern Idaho, causing air quality concerns in this region. To determine the potential air quality impacts of these facilities, we measured ammonia (NH3), methane (CH4), and nitrous oxide (N2O) concentrations over the pens, wastewater storage pond, and composting area on a 700-cow open-lot dairy using open-path Fourier transform infrared spectrometry (OP/FTIR). Concentrations were measured for one or two days at each location during January, March, June, and September. Median NH3 concentrations over the pens, storage pond, and composting area ranged from 0.14 to 0.39 ppmv, 0.04 to 0.17 ppmv, and 0.06 to 0.22 ppmv, respectively, with concentrations tending to be lower in January. Average CH4 concentrations over the pens, storage pond, and composting area ranged from 2.07 to 2.80 ppmv, 1.87 to 2.15 ppmv, and 1.71 to 1.76 ppmv, respectively. Average N2O concentrations ranged from 0.31 to 0.33 ppmv for all areas, which was similar to global background N2O concentrations. Combined ammonia emissions for the pen and storage pond areas, calculated with a backward Lagrangian stochastic inverse-dispersion technique, were 0.04, 0.25, 0.19, and 0.15 kg NH3 cow-1 d-1 for January, March, June, and September, respectively, and methane emissions were 0.34, 0.55, 0.21, and 0.20 kg CH4 cow-1 d-1 for the same months. Assuming this limited monitoring was representative of the entire year, annual emissions from the pens and storage pond were 57 kg NH3 cow-1 and 120 kg CH4 cow-1. These emission rates were similar to the limited number of comparable studies that have been published. However, more extensive monitoring is needed to better quantify variations in emissions throughout the year and among locations.

Specific gravity of Russet Burbank potatoes

Variability in specific gravity of Russet Burbank potatoes was documented in a single 32 hectare field. Maximum variation was 40 units among individual tubers within hills (one unit equals one part in 1000th of specific gravity measurement) and 15 units among hills. Field site variability of 10–15 units was common between sampled grid lines in the field; but bulked samples (truckloads) reduced the sampled variability to 8–10 units. When the samples were taken from bulked lots as opposed to single hill samples, the variability decreased. Grower lots, which were pooled samples from several truckloads, showed specific gravity differences of 2–7 units even though all lots were from the same field. These variations among specific gravity samples should be taken into account when considering total solids content in any lot of potatoes.Degree of russetting of the skin and hollow heart also influenced specific gravity measurements. Measured differences between peeled and unpeeled lots of 10 units in specific gravity corresponded to 2% difference in total solids content. Statistically, the variance of the peeled lot was one half that of the unpeeled lot, therefore, to minimize the measured differences due to skin type, peeled potatoes could be used for the specific gravity measurements.CompendioSe probó la variabilidad en la gravedad específica de las papas Russet Burbank en un solo campo de 32 hectáreas. La variación máaxima entre tubérculos individuales dentro de los puntos de siembra fue de 40 unidades (una unidad es igual a una parte por milésimo de la gravedad específica medida) y 15 unidades entre puntos de siembra. Fue común encontrar una variabilidad de 10–15 unidades entre las diferentes muestras tomadas en el terreno convenientemente dividido; pero muestras al granel (camionadas) redujeron la variabilidad de las muestras a 8–10 unidades. Cuando las muestras fueron tomadas de lotes al granel en oposición a muestras de un solo golpe o punto de siembra, la variabilidad disminuyó. Los lotes de los productores, que fueron una mezcla de muestras tomadas de varias camionadas, mostraron diferencias de 2–7 unidades en la gravedad específica aún en el caso que todos los lotes fueran del mismo campo. Estas variaciones en las muestras, en cuanto a gravedad específica, deben tomarse en cuenta cuando se considere el contenido total de sólidos en cualquier lote de papas.El grado de reticulado de la piel y el de corazón vacío influencian también las mediciones de la gravedad específica. Las diferencias en las mediciones de la gravedad específica entre lotes pelados y sin pelar, que fueron de 10 unidades, corresponden a un 2% de diferencia en el contenido de sólidos totales. Estadísticamente, la variancia de los lotes pelados fue la mitad que la de los lotes sin pelar, por lo tanto, para minimizar las diferencias en las mediciones, debidas a las condiciones de la piel, se podrian usar papas peladas para las medición de la gravedad específica.

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.

Controlling sprinkler irrigation runoff, erosion, and phosphorus loss with straw and polyacrylamide.

Controlling runoff and soil erosion are important for maintaining soil productivity and reducing off-site impairment due to sediment and nutrient enrichment. Previous research has shown that crop residue and polyacrylamide (PAM) can reduce runoff and soil erosion. We compared the combined effects of surface residue and PAM on runoff, soil loss, and phosphorus loss from sprinkler irrigated soil in the laboratory. We hypothesized that surface residue would enhance the effectiveness of sprinkler-applied PAM by allowing PAM to stabilize the soil surface with less disturbance by water drops. Steel boxes (1.5 m long, l.2 m wide, and 0.2 m deep) were filled with Roza loam (fine, smectitic, mesic xerertic Haplocambids) and irrigated at 80 mm h –1 for 15 min. Wheat straw was applied for two separate tests (70% and 30% straw cover). The PAM was applied at 0, 2 or 4 kg ha –1 during the first irrigation, followed by two water-only irrigations. Applying PAM to straw-covered soil controlled runoff, erosion, and phosphorus losses equally or better than using either PAM or straw alone. The 70% straw cover reduced cumulative runoff for the three irrigations 75 to 80% compared to 30 to 50% reduction with PAM alone. Polyacrylamide alone or 30% surface cover alone produced similar results, both reducing cumulative runoff 10 to 20% compared to untreated bare soil. Since runoff, erosion and phosphorus loss were reduced when PAM and surface residue were used individually and to a greater extent when used together, management choices should depend on overall costs and control needed to meet water quality and production goals.

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.

POLYACRYLAMIDE FOR SURFACE IRRIGATION TO INCREASE NUTRIENT- USE EFFICIENCY AND PROTECTWATER QUALITY

Furrow irrigation systems have a greater application capacity, are less costly, and use less energy than sprinkler systems but furrow irrigation produces greater runoff, erosion, and deep percolation losses. Phosphorus (P) and nitrogen (N) losses are associated with runoff sediment, and can be minimized by eliminating irrigationinduced erosion. Excessive leaching of inorganic and organic solutes commonly occurs at the inflow region of furrow irrigated fields where infiltration opportunity times are longer. In one conservation practice, a high molecular weight, anionic polyacrylamide (PAM) is applied to advancing furrow stream flows at a concentration of 10 mg L−1. Because PAM stabilizes furrow soil and flocculates suspended sediment, we hypothesized that this treatment would reduce runoff losses of sediment, molybdate reactive P (MRP), total P, NO3-N, and chemical oxygen demand (COD). Polyacrylamide treatment may increase furrow infiltration in some soils. However, we hypothesized that because it permits higher initial inflows, PAM would not increase NO3-N or Cl leaching relative to conventional, constant inflow irrigation. To test the first hypothesis, all treatments had the same inflow regime. For hypothesis two, control inflows were a constant 15 L min−1; PAM treated in- flows were cut back from 45 to 15 L min−1 after furrow advance. Irrigation runoff and percolation waters were sampled and analyzed. Polyacrylamide increased infiltration and decreased runoff, particularly early in the irrigations. Mean cumulative runoff sediment loss over 12 h was 11.86 kg for each control furrow vs 1.15 kg for PAM-treated furrows. The PAM reduced 12-h cumulative sediment losses in runoff by 90%, MRP by 87%, total P by 92%, and COD by 85%, relative to control furrows. Polyacrylamide had no field-wide, season-long effect on cumulative amounts of water, NO3-N or Cl leached. The PAM-technology effectively prevented soil nutrient losses, increased nutrient-use efficiency, and decreased N and P loads in irrigation return flows and receiving surface waters.