Irrigated Sugarbeet Research Articles

Optimizing nitrogen management to enhance irrigated sugar beet yield and quality

AbstractSugar beet (Beta vulgaris L.) accounts for 55% of the total sugar production in the United States. Optimizing fertilizer nitrogen (N) management is pivotal for its economical and sustainable production and is challenging. Three‐year field experiments (2020–2022) were conducted in western Nebraska to evaluate the effects of fertilizer N rates on beet root yield, sugar concentration, sugar loss to molasses (SLM), estimated recoverable sugar (ERS), and nitrogen use efficiency (NUE). Treatments included 0%, 50%, 80%, 100%, and 125% of recommended N based on the current University of Nebraska‐Lincoln recommendation. Fertilizer application increased the root yield, ERS, and SLM but decreased sugar concentration in most cases compared to the control treatment. Beet NUE decreased with increasing total available N. Linear‐plateau regression models fitted to root yield and ERS response curves showed that the agronomic optimum N rates (AONRs) were 179 and 166 kg N ha−1 for root yield of 68.86 Mg ha−1 and ERS of 11.95 Mg ha−1, respectively. The findings showed that the root yield‐based model required 35% less N rate than the current UNL beet N algorithm, and the ERS‐based model required 13 kg N ha−1 less N rate than the root yield‐based model. Because of the trade‐off effect of total available N on root yield and quality, the ERS‐based N recommendation can be a potential strategy to optimize N management for economic and environmentally sustainable sugar beet production.

Nitrogen use efficiency of drip irrigated sugar beet as affected by sub-optimal levels of nitrogen and irrigation

Sugar beet has strong drought resistance and requires a large amount of nitrogen (N) during growth. Can deficit irrigation combined with low N supply of sugar beet improve water productivity (WP) and N use efficiency (NUE)? In this field study in 2020–2021, two irrigation regimes (W1, field capacity (FC) of the 0–60 cm soil layer was not lower than 70% from 45 days after emergence (DAE) to harvest period; W2, FC of the 0–60 cm soil layer was not lower than 50% in 45–90 DAE, but was consistent with that of W1 after 90 DAE) and three N application rates (0 (N0), 150 (N1), and 225 (N2) kg N ha−1) were designed. Then, their impacts on taproot yield (TY), water consumption (WC) and N uptake (NU) were explored. The results showed that there was no significant difference in TY between W2 and W1 treatments under the N1 and N2 levels. Under the N1 and N2 levels, the daily water consumption (DWC, 0.121 and 0.125 mm ℃d−1) and daily N uptake (DNU, 53.6 and 71.6 g N ℃d−1) of W2 treatment were significantly lower than the DWC (0.161 and 0.164 mm ℃d−1) and DNU (60.6 and 86.5 g N ℃d−1) of W1 treatment in 0–90 DAE. The W2N1 treatment had similar WP and higher NUE compared with the W1N2 treatment. In addition, the fertilizer-15N recovery rate in W2N1 treatment was 8.8% higher than that in W1N2 treatment, the fertilizer-15N loss rate was 6.6% lower than that in W1N2 treatment, but there was no difference in the fertilizer-15N residue between the two. This study clarified that implementing W2 deficit irrigation (50% FC at the canopy rapid growth stage (45–90 DAE)) and N1 nitrogen application rate (33% nitrogen reduction based on 225 kg N ha−1) could not reduce TY but improve WP and NUE.

Biochar Amendment Alleviates the Combined Effects of Salinity and Drought Stress on Water Productivity, Yield and Quality Traits of Sugar Beet (Beta vulgaris L.)

Salinity and drought are two commonly occurring major threats to agricultural yields worldwide, including sugar beet production. Therefore, this work aimed to determine the effectiveness of biochar amendment in improving soil health and alleviating the combined effects induced by salinity and drought on morphological, physiological and biochemical responses of sugar beet plants. Two field studies were established at the experimental farm of Fayoum University, Egypt over two successive winter seasons (2019/2020 and 2020/2021). The experiments were carried out in a split-split plot design with triplicate including three factors: 1) soil salinity, with two levels of ECe (< 4 dS m−1 as control and 10 dS m−1) as main-plot factor; 2) deficit irrigation regimes (I100, I80, and I60) representing 100%, 80%, and 60% of crop evapotranspiration (ETc), respectively as sub-plot factor; and 3) biochar amendment with three application levels (B0 as control, B10, and B20) corresponding to 0, 10, and 20 t ha−1, respectively as sub-sub plot factor. Drought and salinity stress induced significant reduction in growth attributes, relative water content, membrane stability, relative chlorophyll content (SPAD), yield and yield components of sugar beet plants. Meanwhile, the contents of sucrose, proline, Na, K, α amino-N were substantially increased with increasing stress severity. The application of biochar amendment improved the soil physical and chemical properties, resulting in better morphological, physiological and biochemical responses of saline-drought stressed sugar beet plants. Biochar at level (B20) produced the highest values of root yield (95.02 t ha−1) and sugar yield (20.24 t ha−1) for full irrigated sugar beet plants in non-saline soil. Moreover, the application of biochar enhanced water productivity for drought and saline stressed sugar beet plants. Biochar amendment could be effectively used as a helpful agro-management strategy in alleviating the detrimental impacts of salinity and water stress on sugar beet plants, improving soil quality and enhancing water productivity to ensure water sustainability and food security, especially in areas of limited water supply.

Potential of UAV-based sun-induced chlorophyll fluorescence to detect water stress in sugar beet

• SIF parameters from a UAV were used to detect crop water stress. • UAV-based hyperspectral and thermal data assisted the interpretation of SIF response. • The selected SIF indicators were able to track drought recovery after irrigation. • The fluorescence emission yield was more sensitive to drought than the apparent SIF yield. Sun-induced chlorophyll fluorescence (SIF) is a direct indicator of plant photosynthetic activities and can potentially indicate plant physiological changes caused by water stress. However, the direct effect of water stress on the physiological SIF responses in crops at the field level still needs further research to clearly understand the involved mechanisms. To study this relationship, we made use of Unmanned Aerial Vehicles (UAVs), which are flexible and cost-effective to acquire SIF data at a high temporal resolution. We acquired near-infrared SIF (760 nm) and red SIF (687 nm) measurements using a UAV platform over irrigated and non-irrigated sugar beet plots. To represent physiological changes in crops, we calculated the apparent SIF yield (SIF normalized by the absorbed photosynthetically active radiation) at 760 and 687 nm (SIF 760yield and SIF 687yield ), the fluorescence emission yield at 760 nm (ΦF 760 ), and the SIF ratio (the ratio between SIF 687 and SIF 760 ). ΦF 760 was estimated using the recently developed NIRvH approach. For an improved interpretation of the response of these SIF indicators, we also acquired additional UAV-based hyperspectral and thermal data. We found that on June 28, when sugar beets were experiencing water stress, SIF 687yield , ΦF 760 , and SIF ratio all showed a significant response to the recovery of the irrigated sugar beets (p-value < 0.05). On the other hand, on July 24 when both water stress and heat stress affected the crop, only ΦF 760 and SIF ratio weakly tracked the changes induced by the irrigation (p-value < 0.1). ΦF 760 had similar changes to SIF 760yield in both June and July, but ΦF 760 was more sensitive to irrigation. This indicates the importance of correcting for the structural effect when interpreting the SIF response. The findings suggest that SIF indicators can indicate water stress at the field level, but its value to detect the changes of photosynthetic activities under severe stress needs more investigation.

Thermal Crop Water Stress Index Base Line Temperatures for Sugarbeet in Arid Western U.S

Sugarbeet is a deep-rooted crop in unrestricted soil profiles that can readily utilize stored soil water to reduce seasonal irrigation requirements. Soil water below 0.6 m is not commonly considered for irrigation scheduling due to the labor and expense of soil water monitoring at deeper depths and uncertainty in effective rooting depth and soil water holding capacity. Thermal-based crop water stress index (CWSI) irrigation scheduling for sugarbeet has the potential to overcome soil water monitoring limitations and facilitate utilization of stored soil water. In this study, canopy temperature of irrigated sugarbeet under full irrigation (FIT) and 25%FIT in 2014, 2015, 2017 and 2018 in southcentral Idaho and FIT and 60%FIT in 2018 in northwestern Wyoming USA was monitored from full cover through harvest along with meteorological conditions and soil water content. A neural network (NN) was used to predict well-watered canopy temperature based on 15-min average values for solar radiation, air temperature, relative humidity, and wind speed collected -1 to +2.5 hours of solar noon (13:00 – 16:00 MDT). A linear regression driven physical model for estimating the difference between a non-transpiring canopy and air temperature resulted in a value of 13.7 °C for the meteorological conditions of the study. A daily CWSI value calculated as the average 15-min CWSI calculated between 13:00 and 16:00 MDT was well correlated with irrigation amounts and timing. The daily CWSI value provided a more responsive indication of crop water stress than soil water monitoring in deficit irrigation treatments. The methodology used to calculate a daily CWSI could be used in irrigation scheduling to utilize soil water storage without knowledge of soil depth, crop rooting depth, or deep (> 0.6 m) soil water monitoring.

Effect of Ploughing Depths, Irrigation Intervals and Plant Densities on Sugar Beet Yields and Quality تأثیر عمق الحرث وفترات الری والکثافة النباتیة على انتاجیة وجودة نبات بنجر السکر

Under field conditions, two trials were performed through two years of 2015/2016 and 2016/2017 at Galia Al-Kobra, Belqas district, Dakahlia Governorate to investigate the effect of four ploughing depths (15, 20, 25 and 30 cm), two irrigation intervals (every 3 and 5 weeks) and three planting hill spacings (15, 20 and 25 cm) resulted in three plants densities (46666, 35000 and 28000 plants/fed) on sugar beet Oscar poly cultivar growth, yields and quality. The factors were set in s strip-split plot design with 4 replicates. Four ploughing depths, 2 irrigation intervals and 3 planting densities were occupied randomly in the vertical, horizontal and sub-plots, correspondingly . The attained outcomes pointed out that all factors under study individually significantly influenced leaf area index, root fresh weight/plant, dimensions of roots and yields/fed as roots and sugar. Contrary of that, % of sucrose and purity were insignificantly affected by ploughing depth treatments in mutually time of years. All the interactions among the three studied factors significantly affected the above mentioned traits in both years. From the achieved results, it could be suggested that ploughing the soil at 30 cm depth and irrigated sugar beet plant every 3 weeks at the medium planting density (35000 plants/fed) resulted from sowing on 20 cm a part between hills to give the utmost yields and quality beneath the ecological circumstances of this study.

In-season Accumulation and Partitioning of Macronutrients and Micronutrients in Irrigated Sugar Beet Production

In-season Accumulation and Partitioning of Macronutrients and Micronutrients in Irrigated Sugar Beet Production

Yield production functions of irrigated sugarbeet in an arid climate

Increased water demands and drought have resulted in the need to provide data to guide deficit water management decisions in irrigated sugarbeet (Beta vulgaris L.) production. The objective of this study was to quantify the yield response of sugarbeet to water input and actual crop evapotranspiration (ETa) on a soil type (silt loam) common to sugarbeet production in the Northwest U.S. These relationships are valuable to understanding sugarbeet response over a range of water availability and in developing tools to assess future production under water shortages. This paper consolidates data from three studies consisting of ten site-years from 2009 to 2016. The studies were at the USDA-Agricultural Research Service facility in Kimberly, ID on a Portneuf silt loam soil. Treatments consisted of varying levels of cumulative seasonal Kimberly-Penman ET model estimated crop evapotranspiration (ETc) rates ranging from rain-fed to 125% of ETc. Irrigation methods consisted of surface drip irrigation (3 site-years), linear/pivot overhead sprinkler (6 site-years), and solid-set sprinkler (1 site-year). Irrigation frequency was consistent for all studies with applications occurring 2–3 times per week depending on ETc demand. Estimated recoverable sucrose (ERS) yield and root yield were measured, and soil water contents were measured. Across all site-years, quantitative relationships between both actual crop ET (ETa) and water input, and sugarbeet yield and quality variables were developed. Significant (0.05 probability level) positive linear relationships were found between ETa and sugarbeet ERS and root yields (r2 = 0.78). Estimated recoverable sucrose and root yields increased at rates of 19.4 kg ha−1 mm−1 ETa and 0.13 Mg ha−1 mm−1 ETa, respectively. When ETa depths of 719 and 729 mm were reached by the crop, root and ERS yields were maximized, respectively. When water input (irrigation + precipitation) depths of 598 and 605 mm were applied root and ERS yields were maximized, respectively. The quantitative relationships between both ETa and water input, and sugarbeet yields can be used to quantify sugarbeet production under deficit irrigation conditions (data derived from pivot/linear, drip, and solid set irrigation types), which may arise due to water shortage scenarios, or when drought occurs in non-irrigated areas.

Effects of Tillage and Irrigation Management on Sugarbeet Production

Core Ideas Strip tillage and conventional tillage had the same sugar yields under all irrigation levels. Relationships between water input/use and sugarbeet yields were established. Sucrose yields were the same under strip tillage and conventional tillage. Strip tillage reduced runoff and increase water inflitration compared to conventional tillage. Increased water demands and drought have resulted in a need to determine the impact of tillage and deficit water management practices in irrigated sugarbeet (Beta vulgaris L.) production. This study was conducted over three growing season (2011–2015) at the USDA‐Agricultural Research Service facility in Kimberly, ID, on a Portneuf silt loam soil. Treatments consisted of two tillage treatments (strip tillage [ST] and conventional tillage [CT]) and four water input treatments ranging from 100 to 25% of model calculated crop evapotranspiration [ETc]). Estimated recoverable sucrose (ERS) yield, root yield, and sucrose and brei nitrate concentrations were similar for ST and CT across all water treatments. Strip tillage reduced runoff compared to CT. Across all years, quantitative relationships between both actual crop evapotranspiration (ETa) and water input, and sugarbeet yield and quality variables were developed. Significant positive linear relationships were found between ETa and sugarbeet ERS and root yields (r2 values of 0.84 and 0.91, respectively). Estimated recoverable sucrose and root yields increased at rates of 28.5 kg ha−1 mm−1 ETa and 0.194 Mg ha−1 mm−1 ETa, respectively. Equal yield potential for ST, tillage cost savings, and agronomic and environmental benefits associated with soil surface residue indicates ST can be implemented successfully in sugarbeet production systems. The developed quantitative relationships between both ETa and water input, and sugarbeet yield and quality variables can be used to help understand sugarbeet production under deficit irrigation conditions, which may arise due to water shortage scenarios.

Effect of Deficit Irrigation Timing on Sugarbeet

Core Ideas Water allocation timing under drip irrigation effected sugarbeet yield. Excessive water stress early in the season reduced yields. Areas with water shortages have options to grow sugarbeet. Increased water demands and drought have resulted in a need to determine the impact of deficit water management in irrigated sugarbeet (Beta vulgaris L.) production. This study was conducted over 3 yr at USDA‐ARS in Kimberly, ID, on a Portneuf silt loam soil. Eight irrigation treatments consisted of crop evapotranspiration (ETc) rates combined with application timing. Treatments were: W1 Even: approximately (≈) 100% ETc evenly throughout the growing season; W2 Even: ≈65% crop evapotranspiration; W2 Early: ≈100% ETc early in season, ≈55% ETc the remainder of the season; W2 Late: rain‐fed from emergence to end of July, ≈100% ETc the remainder of the season; W3 Even: ≈40% ETc; W3 Early: ≈100% ETc early in season, ≈25% the remainder of the season; W3 Late: rain‐fed through mid‐August, ≈100% ETc the remainder of the season, and rain‐fed: no post emergence irrigation. Results showed that within deficit irrigation treatments, higher yields were obtained when water was applied evenly throughout the season (Even) or ≈100% of ETc was applied early with deficit irrigation later in the season (Early). Thus, the W2 Even and W2 Early treatments had 31.6, 32.9, and 28.2% greater estimated recoverable sucrose (ERS) yields compared to the W2 Late treatment in 2011, 2012, and 2016, respectively. Across all years, ERS yields increased at rates ranging from 17.3 to 22.0 kg ha−1 mm−1 actual crop water evapotranspiration (ETa). Generally, sugarbeet with greater water stress early in the season followed by ≈100% ETc later had lower yields and sucrose content (late treatments).

Irrigated Sugarbeet Sucrose Content in Relation to Growing Season Climatic Conditions in the Northwest U.S.

The potential effects of changing climate on world food production have become a political and scientific focus. This study was conducted to investigate linkages between seasonal climatic conditions and sugarbeet sucrose content in southern Idaho and eastern Oregon. Sucrose content of irrigated sugarbeets delivered to 74 receiving stations in southern Idaho and eastern Oregon from 1997 through 2014, and daily climate data (growing degree days [GDD] and accumulated alfalfa reference crop evapotranspiration, maximum air temperature, minimum air temperature and mean air temperature, global solar radiation, accumulated growing degree days, and mean relative humidity) from regional weather stations were collected and analyzed using various regression techniques to investigate linkages between climate variables and sugarbeet sucrose content. Ninety-nine climatic parameters were analyzed with 34 having correlations with sugarbeet sucrose content > |0.3|. The most important climatic parameter related to mean sucrose content was early stage sugarbeet growth (late April to mid-May). In general, as temperature and GDD increased sucrose content decreased. Results indicate increases in both early season and mid-season temperatures will lead to decreases in sugarbeet sucrose concentrations. However, if sugarbeet root yields increase due to increasing temperatures and GDD accumulation, the sucrose yield changes would be buffered.

Soil surface cover on irrigated rotations for potato ( Solanum tuberosum L.), dry bean ( Phaseolus vulgaris L.), sugar beet ( Beta vulgaris L.), and soft white spring wheat ( Triticum aestivum L.) in southern Alberta

Soil surface cover (crop residue and fall-seeded cover crops) during the nongrowing season is an important tenet of sustainable agriculture, reducing wind and water erosion risk and enhancing soil water conservation. Expansion of irrigated row crop production, namely, potato (Solanum tuberosum L.), dry bean (Phaseolus vulgaris L.), and sugar beet (Beta vulgaris L.), in southern Alberta in the late 1990s prompted a 12-year (2000 to 2011) study to evaluate rotations and soil management systems for improved soil quality. The study compared conservation (CONS) and conventional (CONV) management systems in three- to six-year rotations. Conservation management included cover crops; reduced tillage; feedlot manure compost addition; and solid-seeded, narrow-row dry bean production. Beginning in the third year of the study (2002), surface residue cover was estimated each spring prior to tillage or seeding. Averaged over 10 years (2002 to 2011), residue cover was significantly higher on CONS (15.6%) versus CONV (7.1%) management. Cover was significantly higher where wheat (Triticum aestivum L.) was the previous crop (33.7%) compared to narrow-row dry bean (9.7%), which was significantly higher than potato and sugar beet (6.5% to 6.7%), which were in turn significantly higher than wide-row bean (3.6%). Inclusion of a fall rye (Secale cereale L.) cover crop after potato or dry bean increased residue cover close to or more than 30%, the threshold required to reduce wind erosion risk. Long-term replacement of cereals with lower residue-producing crops (e.g., potato, dry bean, and sugar beet) on irrigated rotations in southern Alberta should be considered judiciously in light of potential negative effects on surface residue cover.

Strip Tillage and High‐Efficiency Irrigation Applied to a Sugarbeet–Barley Rotation

Strip tillage (ST) and high‐efficiency overhead irrigation methods reduce fuel and water inputs compared to conventional practices, but have not been extensively evaluated in sugarbeet (Beta vulgaris L.)–malt barley (Hordeum vulgare L.) cropping systems. A field study comparing conventional tillage (CT) and ST systems and two sprinkler irrigation methods (mid‐elevation spray application, MESA; low‐energy precision application, LEPA) was conducted near Sidney, MT, from 2004 to 2008. Strip tillage was performed (for sugarbeet only) using a single operation that left alternating 30‐cm wide strips of tilled and untilled soil while fertilizer was simultaneously banded 10 cm below the seed row. Conventional tillage for sugarbeet consisted of six separate tillage operations following a broadcast application of fertilizer. Tillage preceding malt barley consisted of one pass each with a disk and a field cultivator following a broadcast application of fertilizer. Sugarbeet grown with ST yielded as well as when grown with CT. Irrigation method did not affect sugarbeet yield. Malt barley yield was not affected by irrigation method but was 5.4% lower following ST sugarbeet than when following CT sugarbeet. Tillage and fertilizer application costs for the sugarbeet phase of the 2‐yr rotation were estimated to be approximately $141 ha−1 less with ST than with CT representing reductions of 66% for the sugarbeet phase alone and 47% for the 2‐yr cropping system. It was concluded that both ST and LEPA are applicable to irrigated sugarbeet–malt barley cropping systems and may provide substantial cost savings compared to conventional practices.

Nitrogen effects on yield, quality and K/Na selectivity of sugar beets grown on clays under semi-arid, irrigated conditions

In a four-year experiment, five nitrogen rates (0, 60, 120, 180 and 240 kg N ha -1 ) were tested over irrigated sugar beets grown on clays, under Mediterranean conditions, in central Greece. There, sugar beets are commonly grown under water shortages, high temperatures and high soil Na concentrations. Contrary to previous reports, N rates did not affect significantly population density (as assessed by root number at harvest) and sucrose content in fresh and dry root weight (SC and SCD, respectively). Yield response to N was year dependent and only in one out of four seasons, was there a positive effect of N on sugar yield and white sugar yield. In that case, the estimated optimum N dose was high (220 kg N ha -1 ). Increasing N rates increased significantly N assimilation (as assessed by petiole NO3-N and root α-amino N) and water content in root (WCR) but decreased biomass partitioning to root (lower harvest index). Selective absorption (SA, the preferential uptake of K over Na in roots) decreased with increasing N rates and it was negatively correlated with sugar beet N nutrition indices (petiole NO3-N and root α-amino N). A negative correlation between SA and petiole NO3-N was also evident when data combined over years, indicating that strong Na exclusion was associated with poor N nutrition, a contradiction to previous reports. The higher the SA, the lower the WCR indicating less dilution of sucrose in root and thus, the higher the SC. Moreover, high SA evoked sucrose accumulation in roots as it was shown by its positive correlation with SCD.

Potential of Some Sweet Sorghum (Sorghum bicolor L.) Genotypes Under Two Water Regimes for Sugar and Bio-ethanol Production

During the last years, the total annual production of sugar in Syria has been fluctuating, but the demand of sugar is increasing rapidly. The irrigated sugar beet covers only about 40 % of the total local sugar demand; and large quantities of sugar are imported. Sweet sorghum, also called “sugar cane of desert”, has emerged as a smart dual purpose and alternative crop providing food, feed, sugar and second generation bio-fuel without threatening food security and natural resources. Current study was conducted to estimate the sugar and bio-ethanol production potential of nine introduced varieties of sweet sorghum, along with a local cultivar ‘Razineah’ as control, under two water regimes; well watered (WW) and low moisture stress (LMS), during the summer season of 2010, very high daily maximal temperatures attaining around 45 °C in the field. This factor constituted another selection pressure to the trail. A wide range of variability among the ten genotypes in terms of stalk yield, Brix (%), sugar and bio-ethanol potential yield. In addition the higher Brix readings under LMS for most varieties were compensated by reduction in juice content in sugar stems, as a consequence sugar yield affected with the reduction in juice yield. Significant positive correlation between cane components (height, diameter) with stalk yield and juice yield under both WW and LMS conditions was observed. Highly positive significant correlation was observed between stalk yield, juice yield and days to 50 % flowering under LMS condition, and a significant negative correlation was observed between Brix with stalk yield and juice yield under LMS. One genotype ICSSH 30 was superior among the others in terms of drought-tolerance associated traits and high sugar and bio-ethanol potential yield under both water regimes.

The economic feasibility of sugar beet biofuel production in central North Dakota

Abstract This study examines the financial feasibility of producing ethanol biofuel from sugar beets in central North Dakota. Under the Energy Independence and Security Act (EISA) of 2007, biofuel from sugar beets uniquely qualifies as an “advanced biofuel”. EISA mandates production of 21 billion gallons of advanced biofuels annually by 2022. A stochastic simulation financial model was calibrated with irrigated sugar beet data from central North Dakota to determine economic feasibility and risks of production for 0.038 hm 3 y −1 (or 10 MGY (Million Gallon per Year) and 0.076 hm 3 y −1 (or 20 MGY) ethanol plants. Study results indicate that feedstock costs, which include sugar beets and beet molasses, account for more than 70 percent of total production expenses. The estimated breakeven ethanol price for the 0.076 hm 3 y −1 plant is $400 m −3 ($1.52 per gallon) and $450 m −3 ($1.71 per gallon) for the 0.038 hm 3 y −1 plant. Breakeven prices for feedstocks are also estimated and show that the 0.076 hm 3 y −1 plant can tolerate greater ethanol and feedstock price risks than the 0.038 hm 3 y −1 plant. Our results also show that one of the most important factors that affect investment success is the price of ethanol. At an ethanol price of $484.21 m −3 ($1.84 per gallon), and assuming other factors remain unchanged, the estimated net present value (NPV) for the 0.076 hm 3 y −1 plant is $41.54 million. By comparison, the estimated NPV for the 0.038 hm 3 y −1 plant is only $8.30 million. Other factors such as changes in prices of co-products and utilities have a relatively minor effect on investment viability.

Tillage Depth Effects on Soil Physical Properties, Sugarbeet Yield, and Sugarbeet Quality

Tillage depth influences the soil–water–plant ecosystem, thereby affecting crop yield and quality. The effects of tillage depth on soil physical properties and sugarbeet (Beta vulgaris L.) yield and quality were evaluated. A field study composed of two tillage depths [10 cm, referred to as shallow (ST), and 20 cm, referred to as deep (DT)] was conducted on a Lihen sandy loam soil in spring 2007 at the Agricultural Research Service (ARS) irrigated research farm near Williston, North Dakota. Soil bulk density (ρb), gravimetric water content (θw), and saturated hydraulic conductivity (Ks) were measured three times during the growing season at four depth increments to 40 cm deep. Samples were taken approximately 0.5 m apart within the crop row of irrigated sugarbeet. Soil air-filled pore volume (εa) was calculated from soil bulk density and water content data. Soil penetration resistance (PR) was also measured in 2.5-cm increments to a depth of 35 cm. Roots were hand-harvested from each plot, and each sample consisted of the roots within an area consisting of two adjacent rows 1.5 m long. Soil ρb was greater in ST than in DT, whereas Ks was greater with DT than with ST. Soil PR was significantly greater in ST than in DT at the 0- to 20-cm depth. Soil θw and εa were slightly greater in DT than those under ST. Although tillage depth had no significant effect on sugarbeet population, root yield, or sucrose content, a small difference in sucrose yield between two depths of tillage may be attributed to reduced ρb, increased water intake, improved aeration, and increased response to nitrogen uptake under DT than under ST. It was concluded that tillage depth enhanced soil physical quality and had little effect on sugarbeet yield or quality.

Plasticity of leaf anatomy, chemistry and water economy of irrigated sugar beets grown under Mediterranean conditions

In a three-year (2004-2006), field experiment, we aimed to study changes in leaf physiological traits (leaf water potential-Ψleaf, leaf water content-LWC, carbon isotope discrimination-Δ, specific leaf area-SLA, chlorophyll content as assessed by SPAD and modified SPAD-MSPAD) and elemental composition (K, Na, Ca, Mg, K/Na, Ca/Mg, total leaf salinity-TLS) of sugar beets (cv. Rizor) grown under Mediterranean, irrigated conditions. Each year, soil moisture content (SMC) and leaf parameters were determined 11 times from early June to the end of October. Growing seasons differed as regards water inputs with 2004 being the driest and 2006 being the wettest. Leaf physiology and chemistry showed plasticity to water availability and significant differences were found between years (except for Ca), sampling time and their interaction. Ψleaf, LWC, Δ, SLA, K/Na and Ca/Mg were positively affected by SMC while the adverse was evident for chlorophyll content (SPAD and MSPAD), Na, Ca, Mg and TLS. As a Chenopodiaceae, sugar beet used leaf succulence, lowering SLA, to cope with water shortage and maintain LWC ca 90%. Low SLA was related with low Ψleaf and Δ values. Succulent leaves were characterized by increased leaf salinity and chlorophyll accumulation, which was ascribed to increased Mg concentrations. Leaf salinity and mainly Na had a negative impact on Δ. Antagonistic effects of K on Na or Mg and synergistic effects of Na on Ca and Mg were recorded.

Tillage Effects on Physical Properties in Two Soils of the Northern Great Plains

Tillage practices profoundly affect soil physical and hydraulic properties. It is essential to select a tillage practice that sustains the soil physical properties required for successful growth of agricultural crops. We evaluated the effects of conventional (CT) and strip (ST) tillage practices on bulk density (rho(b)), gravimetric water content (theta(w)), and saturated hydraulic conductivity (K(s)) at the soil surface and at 10- to 15-cm depth in two soils of the Northern Great Plains (NGP). Soil cores were collected from each plot at 0- to 10- and 10- to 20-cm depths under each tillage practice at both sites to measure rho(b) and theta(w). In-situ K(s) measurements at the soil surface and at 10- to 15-cm depth were determined using a pressure head infiltrometer (PHI) and a constant head well permeameter (CHWP), respectively, at two sites, one in North Dakota (Nesson, mapped as Lihen sandy loam) and one in Montana (EARC, mapped as Savage clay loam). The K(s) measurements were made approximately 1 m apart in the center of crop rows within CT and ST plots of irrigated sugarbeet ( Beta vulgaris L.). Tillage treatments significantly affected soil rho(b) and theta(w) in clay loam soil at the EARC site, while rho(b) and theta(w) did not differ between CT and ST in sandy loam at the Nesson site. The log-transformed K(s) at the soil surface did not differ significantly between CT and ST practices at either site. The effect of tillage on log-transformed K(s) at the 10- to 15-cm depth was significant in both sandy loam and clay loam soils at P < 0.10 and 0.05 levels, respectively. The K(s) values at 10- to 15-cm depth were 23% and 138% greater for ST than for CT at Nesson and EARC sites, respectively. Differences in soil compaction as evaluated through rho(b) data at 10- to 20-cm depth explain K(s) variations between the CT and ST systems at both sites. It was concluded that the CT operations increased soil compaction, which consequently altered rho(b), thereby reducing K(s) in the soil.

Development of Strip Tillage on Sprinkler Irrigated Sugarbeet

A project to evaluate new technologies for strip tillage of small seeded crops was initiated in fall 2003 near Sidney, Montana, for sprinkler irrigated sugarbeet (Beta vulgaris L.) to be grown in 2004. Strip till treatments were compared to conventional grower tillage practices in fifty-six 15- 25-m (48- 80-ft) side-by-side plots. Both treatments were flat planted with no ridges or beds. All strip tillage and fertilization was done in the fall after removal of a malt barley crop. Conventional tillage was done in the fall at the Sidney site and in the spring at the Nesson site. Thirty-centimeter (12-in.) wide strips were tilled directly into the straw residues about 20 cm (8 in.) deep using straight and paired fluted coulters and a modified parabolic ripping shank followed by a crows-foot packer wheel. Toothed-wheel row cleaners were installed in front of the straight coulter to move loose residue to the side to avoid plugging. At the same time, dry fertilizer was shanked (banded) about 8 to 13 cm (3 to 5 in.) below the anticipated seed placement location. Sugarbeet were planted about 2.5 cm (1 in.) deep with 60-cm (24-in.) spacing between rows in the spring. Toothed-wheel row cleaners were also placed in front of each row on the planter to move any residue displaced by winter storms. Operation of the strip tillage machine required about 25 tractor horsepower per row, but substantial fuel savings were realized with this system by reducing the number of tractor equipment field passes by up to 75%. In 2004, 2006, 2007, and 2008 there were no significant differences in yields or sugar production between the two tillage treatments; however, in 2005 the strip tilled plots produced about 17% greater yields (tonnage and gross sugar). This benefit in 2005 was primarily due to the standing straw stubble in the strip tilled plots that protected sugarbeet seedlings from blowing soil during a spring wind storm that severely damaged seedlings in the conventionally tilled plots where there was no surface crop residue. It was concluded that strip tillage must be considered as part of a larger cropping system that affects timing and equipment choices for planting, cultivation, spraying, and harvesting as well as tillage and other cultural practices. Based on these results, it is generally recommended that strip tillage should be performed in the fall on clay soils in eastern Montana where it has been shown to result in better seedbed conditions than spring strip tillage. Whereas lighter, sandy soils would probably produce equally well when strip tilled in the spring, which could then be combined with planting into a single pass tillage, fertilizing, and planting operation. Banding fertilizer is highly recommended under strip till to increase fertilizer use efficiencies and reduce input costs. RTK-GPS guided steering in combination with some type of mechanical steering assistance on the implements are also recommended for both strip tilling, planting, and cultivation (if needed).