bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance of Two Nitrification Inhibitors Over a Winter with Exceptionally Heavy Snowfall
Authors: Goos R. Jay , Johnson Brian E.
Published: July 2010

Fall application of NH3for spring wheat (Triticum aestivumL.) is common in the northern Great Plains. Two field sites were established in eastern North Dakota, with the objective of measuring the relative rate of fall and overwinter nitrification as influenced by two nitrification inhibitors, nitrapyrin and ammonium thiosulfate (ATS). Aqua ammonia was injected into the soil in early October 1996, alone, with nitrapyrin (0.56 and 1.68 kg ha−1), or with ATS (17 kg S ha−1). The N rate was 84 kg ha−1. The winter of 1996–1997 was very unusual, with about 3 m of snowfall—three times the average snowfall in southeastern North Dakota. Nitrapyrin and ATS were effective in slowing nitrification in the fall and both inhibitors increased the amount of mineral N found in the fertilizer bands in the spring at both sites. One site was planted to ‘Pioneer 2375’ spring wheat. Overwinter N loss, presumably by denitrification, was severe. Amending the ammonia with nitrapyrin or ATS greatly increased wheat growth, N uptake, and grain yield. The apparent N uptake efficiency into the grain + straw was 24% for the unamended aqua ammonia, but was 50 to 56% when nitrapyrin or ATS was used. These results probably define a worst‐case scenario regarding the performance of fall‐applied ammonia in this area, and suggest that both nitrapyrin and ATS have value as nitrification inhibitors with fall‐banded N.
Response of Overseeded Alfalfa and Bermudagrass to Alfalfa Row Spacing and Nitrogen Rate
Authors: Haby Vincent A. , Davis J. V. , Leonard A. T.
Published: July 2010

Alfalfa (Medicago sativaL.) is a rare forage crop on Coastal Plain soils. Acid soils, wet conditions, and the prevalence of perennial, warm‐season grasses limit alfalfa production. Development of grazing‐tolerant varieties raised interest in growing alfalfa on the Coastal Plain. This three‐year dryland field study was conducted to evaluate coincident production of ‘Alfagraze’ alfalfa and ‘Coastal’ bermudagrass [Cynodon dactylon(L.) Pers.] as a sustainable forage system. Limestone (effective calcium carbonate equivalence ECCE 72%) at a rate of 6.1 t ha−1was incorporated by roto‐tilling 15 cm deep in an established sod of Coastal bermudagrass on a Darco loamy fine sand (loamy, siliceous, thermic Grossarenic Paleudults) in late winter 1990, with an additional 3 t ha−1surface‐applied in June 1991. Alfalfa was seeded in October 1990 at 23, 46, 69, and 92 cm between rows in main plots of a split‐plot design. Nitrogen rates from 0 to 112 kg ha−1in increments of 28 kg ha−1were applied to subplots for every bermudagrass regrowth cycle. Other plant nutrients (including P, K, Mg, S, B, Zn, and Cu) were applied at rates considered adequate for alfalfa on a low‐fertility soil. Yield of alfalfa at the 23‐cm row spacing in 1991 was 8.8 t ha−1and declined to 6.7 t ha−1at, while yield of bermudagrass increased from 3.2 to 5.7 t ha−1, respectively, at these row spacings. In 1992, alfalfa yield increased an additional 2.2 t ha−1at each row spacing, with a compensating decline in bermudagrass production. Alfalfa yielded 11 t ha−1at all row spacings in 1993, despite a midseason drought, while bermudagrass yield was <450 kg ha−1. Row spacing had no effect on total forage production in any year. Higher N rates increased bermudagrass yield the first two years. Applied N increased alfalfa yield at certain harvests, but had no effect on total annual production. Crude protein in alfalfa declined or remained similar as row spacing was widened. Soil pH was lowered by increasing N rates and by narrower alfalfa row spacings. Results indicate that alfalfa competes well with Coastal bermudagrass, even in drought conditions.
Establishment of Temperate Pasture Species into Alfalfa by Frost‐Seeding
Authors: Casler Michael D. , West David C. , Undersander Daniel J.
Published: July 2010

Mature alfalfa (Medicago sativa L.) stands are generally unsuitable as pastures because of their low plant density and the relative inability of alfalfa plants to tolerate grazing pressure. The objective of this research was to determine the potential for introducing new species into mature or declining alfalfa stands by frost‐seeding. Experiments were conducted in 1995 and 1996 at the University of Wisconsin Agricultural Research Stations near Arlington, WI (four sites), and Lancaster, WI (three sites). Smooth bromegrass (Bromus inermis Leyss.), orchardgrass (Dactylis glomerata L.), perennial ryegrass (Lolium perenne L.), reed canarygrass (Phalaris arundinacea L.), timothy (Phleum pratense L.), and red clover (Trifolium pratense L.) were frost‐seeded into mature alfalfa stands at seeding rates of 0, 55, 110, 220, 440, and 880 seeds m−2. Competition from existing vegetation was reduced by clipping the fields in the autumn prior to seeding and harvesting (by either grazing or clipping) during the seeding year. Seedling counts were taken approximately 60 and 90 d after seeding. Seedling densities were similar at 60 and 90 d after seeding in both years. There was variability in the magnitude of species establishment and density among sites, but species ranking order was fairly consistent across sites. Species ranking for seedling density was perennial ryegrass > orchardgrass, smooth bromegrass, and red clover > timothy and reed canarygrass (59, 28, 20, 22, 13, and 5 seedlings m−2, respectively). All species showed a linear or quadratic response to increasing seeding rate, but the response varied with species. Results of this research indicate that establishment of these species by frost‐seeding is possible and that this technique can increase plant diversity within pastures.
Potassium Deficiency Increases Specific Leaf Weights and Leaf Glucose Levels in Field‐Grown Cotton
Authors: Pettigrew William T.
Published: July 2010

Potassium deficiency reduces lint yield and causes fiber quality problems for cotton (Gossypium hirsutum L.) producers throughout the U.S. production regions. This deficiency produces plants exhibiting reduced leaf area but increased specific leaf weights (SLW). The objectives of this research were (i) to determine whether the alterations in leaf growth produced by a K deficiency are associated with changes in leaf carbohydrate levels or leaf water status and (ii) to determine if a K deficiency alters the carbohydrate concentration in root tissue. Field studies were conducted in 1993 and 1994 using four genotypes (‘DES 119’, ‘MD 51 ne’, ‘Prema’, and ‘STV 825’) and two levels of K fertilization (0 and 112 kg K ha−1). Glucose, fructose, sucrose, and starch concentrations were quantified for leaves collected at three different dates in both years. Root carbohydrate concentrations were determined once in each growing season. Leaf water potential and its components were determined once each growing season using thermocouple psychrometers. Glucose was the only carbohydrate whose leaf concentration was consistently altered by the K deficiency; it was increased an average of 84% across all leaf harvest dates. Leaf concentrations of starch, sucrose, and fructose were inconsistent in their response to variation in K levels. The K deficiency increased root tissue concentrations of starch by 82%, glucose by 14%, and fructose by 27%, averaged across years. Although leaf water potential (ψl) and leaf osmotic potential (ψπ) were unaffected by varying the level of K fertilization, leaf turgor (ψt) averaged across both years was increased 17% in leaves from the K‐deficient plants. The elevated carbohydrate concentrations remaining in source tissue, such as leaves, appear to be part of the overall effect of K deficiency in reducing the amount of photosynthate available for reproductive sinks and thereby producing reductions in lint yield and fiber quality seen in cotton.
Errors Associated with the Use of Soil Survey Data for Estimating Plant‐Available Water at a Regional Scale
Authors: Fortin Marie‐Claude , Moon David E.
Published: July 2010

Agricultural models generally provide estimation procedures for soil properties that regularly are missing in data sets. In regional model applications, the inputs to these procedures are often derived from soil survey information. This study was conducted to determine two types of errors associated with the use of soil survey data for estimating plant‐available water (PAW) for the Peace River region of British Columbia: the error associated with the use of an estimation procedure and the error associated with the use of soil survey data rather than measured data as inputs for the procedure. Two PAW estimation procedures (one used in CERES–Maize and in EPIC, and a recent update) were evaluated against laboratory‐measured water‐holding capacity. The original procedure did not perform adequately, with a prediction error of 0.10 compared with 0.04 for the updated procedure. Prediction error for procedure inputs derived from soil survey data were 8 to 18% of the value of the measured mean for particle size and as much as 51% for organic C. The updated procedure was relatively insensitive to input prediction errors. Prediction errors for horizon thickness were 38 mm for the Ap and 95 mm for the main B horizons, the single largest source of error in this study. Prediction errors for total PAW were 25 and 33% of the mean for the Ap and main B horizons, respectively. Tests for unbiasedness for total PAW failed. Field measurements are needed to validate the best of the two estimation procedures and to supplement the present horizon thickness values found in soil survey. These field measurements represent a significant investment of time and money, but are essential to optimize the allocation of resources for a modeling project at the regional scale.
Stover and Potassium Management in an Upland Rice–Soybean Rotation on an Indonesian Ultisol
Authors: S. Dierolf Thomas , Yost Russ S.
Published: July 2010

Fertilizer and stover management greatly determine the extent of K deficiency on weathered, low‐K soils in the humid tropics. This study quantified the effects of K fertilization and stover management on soil properties and crop yields on a Typic Kanhapludult in Indonesia. Cowpea [Vigna unguiculata (L.) Walp. subsp. unguiculata]–cowpea–rice (Oryza sativa L.)–soybean [Glycine max (L.) Merr.]–rice–soybean were grown during a 2‐yr period. Fertilizer KCl was applied as 70 and 250 kg K ha−1 to the first crop only, and as a total of 250 and 600 kg K ha−1 applied to several crops. The effect of stover removal or return was examined for each K rate. Critical soil K levels were 0.14 cmolc kg−1 for the final rice crop and 0.14 and 0.16 cmolc kg−1 for the two soybean crops. By returning stover, a single application of 70 kg K ha−1 to the first crop was adequate to maintain soil K above the critical level for all six crops. When stover was removed, a total of 250 kg K ha−1 applied during several crops maintained soil K above critical levels. A one‐time 250 kg K ha−1 application to the first crop, however, resulted in yield declines by the fifth crop. A maintenance rate of about 45 kg K ha−1 per crop was required when stover was removed. Stover removal also hastened soil Mg depletion, and thus a maintenance rate of about 6 kg Mg ha−1 crop−1 is recommended.
Cover Crops for Sweet Corn Production in a Short‐Season Environment
Authors: Griffin Tim , Liebman Matt , Jemison John
Published: July 2010

Legume cover crops can supply all or most of the N required by a subsequent crop if legume biomass is of sufficient quantity and N mineralization is approximately synchronous with crop demand. Three 2‐yr crop rotation cycles were conducted on a Lamoine silt loam (fine, illitic, nonacid, frigid Aeric Epiaquept) soil in Maine to (i) evaluate biomass and N accumulation of alfalfa (Medicago sativaL.), winter rye (Secale cerealeL.), and hairy vetch (Vicia villosaRoth subsp.villosa) plus winter rye cover crops; (ii) determine sweet corn (Zea maysL.) response to legume and fertilizer N sources in a barley (Hordeum vulgareL.)–sweet corn rotation; and (iii) assess the accuracy of the presidedress soil nitrate test (PSNT) and leaf chlorophyll N test (LCNT) for distinguishing N‐responsive and nonresponsive sweet corn. Both legumes accumulated more N than rye grown alone, although total biomass was similar. Sweet corn following rye always exhibited a linear response to N fertilizer (up to 156 kg N ha−1), but generally exhibited no response to added N following either alfalfa or hairy vetch plus winter rye (VR). Both PSNT and LCNT were 75% accurate in identifying plots responsive to additional fertilizer N. The legume cover crops grown were able to replace all or nearly all of the N fertilizer required by a subsequent sweet corn crop, with fertilizer replacement values (FRVs) of 58 to 156 kg N ha−1in a short‐season environment. These cover crops are a viable alternative source of N, greatly reducing or eliminating the need for N fertilizer.
Contour Grass Strips and Tillage Affect Corn Production on Philippine Steepland Oxisols
Authors: Thapa B. B. , Garrity D. P. , Cassel D. K. , Mercado A. R.
Published: July 2010

Cultivated steeplands in the humid tropics require better soil management systems to meet increasing food demands. The objective of this 4‐yr study was to evaluate the following four contour soil management systems for corn (Zea maysL.) production: (i) contour moldboard plowing (CP); (ii) ridge tillage (RT); (iii) natural grass barrier strips plus moldboard plowing (GCP); and (iv) grass strips plus ridge tillage (GRT). Eight successive corn crops were grown in limed and fertilized soil from 1992 through 1995. On a total land area basis (cropped area plus the area occupied by the grass strips), the 1995 mean grain yields for RT (10.8 Mg ha−1) and GRT (10.3 Mg ha−1) were significantly greater than yields for CP (10.0 Mg ha−1) and GCP (9.6 Mg ha−1). The corn grain yields for the CP and RT systems before 1995 ranged from 1.3 Mg ha−1in 1992 to 8.4 Mg ha−1in 1993, while comparable GCP and GRT yields ranged from 1.4 to 7.6 Mg ha−1. Excluding the area occupied by the grass strips, the GRT system had the highest 4‐yr average corn yield (7.3 Mg ha−1) followed by the GCP (7.2 Mg ha−1), RT (6.9 Mg ha−1) and CP (6.7 Mg ha−1) systems. Yields improved during the 1994 and 1995 growing seasons when the grass was not permitted to grow as tall. The combination of contour ridge tillage and contour grass strips has potential for sustaining crop productivity on highly erodible steepland soils in the humid tropics.
Summer Accumulation of Tall Fescue at Low Elevations in the Piedmont: I. Fall Yield and Nutritive Value
Authors: Burns Joseph C. , Chamblee Douglas S.
Published: July 2010

Summer accumulation of tall fescue (Festuca arundinacea Schreb.) for fall and winter use in the Piedmont, a region of the USA of moderate fall and winter temperatures and open winters of frequent rainfall, has not been well documented. We determined in this 5‐yr study the yield and nutritive value in mid‐November of tall fescue accumulated monthly from 1 June to 1 September. A fifth treatment included an additional 67 kg N ha−1 applied at the 1 July accumulation date. The site was a Cecil clay loam (fine, kaolinitic, thermic Typic Kanhapludults) soil and the treatments were arranged in a randomized complete block design with four replicates. Summer accumulations yielded from 3280 to 4130 kg ha−1 with a mean linear (P ≤ 0.05) reduction in dry matter of 195 kg ha−1 for each week's delay in accumulation from 1 June until 1 September. In two of the three years, highest (P ≤ 0.05) dry matter yields (DMY) resulted from the 1 June date (4070 to 5440 kg ha−1) and lowest (P ≤ 0.05) from the 1 September date (1010 and 860 g kg−1). Repeated summer accumulations did not alter DMY (P < 0.01) in subsequent falls or in the following spring. At mid‐November in vitro dry matter disappearance (IVDMD) had increased 30 g kg−1 for each 30‐d delay in accumulation from 1 June to 1 September, but no change occurred in crude protein (CP) (mean = 120 g kg−1). Summer accumulation of tall fescue for fall grazing can be practiced in the lower Piedmont with accumulation beginning as early as 1 June.
Toward the Discrimination of Manganese, Zinc, Copper, and Iron Deficiency in ‘Bragg’ Soybean Using Spectral Detection Methods
Authors: Adams Matthew L. , Norvell Wendell A. , Philpot William D. , Peverly John H.
Published: July 2010

Early visual symptoms of Mn, Zn, Cu, and Fe deficiency are often difficult to interpret and incorrect diagnoses are common. Reflectance and fluorescence measures may be useful for early and more reliable detection of Mn, Zn, Cu, and Fe deficiencies, but only if one or more spectral measures change uniquely with each deficiency. A discriminant analysis was performed to determine whether selected fluorescence and reflectance measures could be used to discriminate effectively marginal Mn, Zn, Cu, Fe deficiencies, and nutrient‐adequate soybean [Glycine max (L.) Merr. cv. Bragg] leaves from plants grown in solution culture. Predictors were yellowness index (YI), a new measure sensitive to chlorosis; normalized difference vegetation index (NDVI); the ratio of minimal fluorescence (Fo) to variable fluorescence (Fv), Fo/Fv; and the ratio of minimal fluorescence to the fluorescence yield after 5 min of illumination (F5min), Fo/F5min. Manganese, Zn, Cu, and Fe deficiencies were correctly identified 62, 40, 92, and 30% of the time, respectively, as estimated by cross‐validation. Controls were identified correctly 77% of the time. One‐third to one‐half of the leaves identified as nutrient deficient by tissue analysis did not exhibit visual symptoms. Lack of a spectral measure sensitive specifically to Zn and Fe deficiency contributed to the low identification rates for Zn and Fe deficiencies. While the development of spectral measures sensitive to Zn and Fe deficiencies is required for further development of this rule, discriminant analysis is a suitable method for the development of classification rules for identifying marginal stresses.
Nitrogen Management in No‐Tillage Grain Sorghum Production: I. Rate and Time of Application
Authors: Khosla Raj , Alley Mark M. , Davis Paul H.
Published: July 2010

Grain sorghum [Sorghum bicolor(L.) Moench] is grown in rotation with wheat (Triticum aestivumL.) and soybean [Glycine max(L.) Merr.] in the mid‐Atlantic. Sufficient data on N fertilization of sorghum are not available for this region. Our objective was to evaluate the influence of multi‐rate N fertilization on dryland sorghum. Treatments consisted of factorial combinations of four starter‐band N rates (11, 34, 56, and 78 kg N ha−1) and four sidedress N rates (0, 45, 90, and 134 kg N ha−1). A broadcast treatment of 67 kg N ha−1at planting was also included. Starter‐band was applied 5 cm to the side and below the seed. Sidedress was applied 35 days after emergence at the eight‐leaf growth stage. Grain yield ranged from 1.7 to 11.9 Mg ha−1over eight site‐years and was responsive and nonresponsive to N applications on four sites each. Nonresponsiveness was either due to high levels (>85 kg N ha−1) of residual soil mineral N, or severe water stress conditions. Our results indicate that production of sorghum on soils testing high in mineral N (50 kg N ha−1in the surface 0.3 m) at planting should not receive any starter‐band N in conjunction with sidedress N application of 130 kg N ha−1for optimum economic return to N fertilization. For soils testing low in mineral N, 40 kg N ha−1starter‐band in conjunction with 130 kg N ha−1sidedress N should optimize the sorghum yields in most situations.
An Integrated Approach of Breeding and Maintaining an Elite Cultivar of Snap Bean
Authors: Traka‐Mavrona Ekaterini , Georgakis Dimitrios , Koutsika‐Sotiriou Metaxia , Pritsa Theodora
Published: July 2010

This study is an attempt to describe a functional breeding and maintaining program of intraselection in a traditional snap bean (Phaseolus vulgarisL.) cultivar. The program was applied in three stages. The first thing examined was the existing genetic variability of source material for earliness and pod yield potential. Single‐plant frequency distributions with positive skewness for earliness showed that the frequency of unfavorable alleles was high. For total pod yield, distribution was found normal. Thus, the end‐target should be selection for early maturity, keeping, and stabilizing high yield. The seed shape uniformity was added as third criterion of selection. Secondly, combined pedigree intraselection, based on widely spaced single‐plant performance, for the prementioned traits was applied for three successive generations. The evaluation of the third‐generation families revealed progenies with high yield, earliness, and stability of performance. Thirdly, the end‐product of the program applied was to restore or even improve the cultivar. The evaluation of improved selections of fourth‐generation families and of the source material, at dense stand, showed that all families were the only ones producing high and stable early fresh pod harvest, even 53 d after planting (53.25–80 g/plant, compared with 0 g/plant of the control). The total pod yield of all the families was 219 to 276% superior compared with source material. Conclusively, the widely spaced single‐plant combined pedigree intraselection was proved reliable and effective in restoring or even improving the local cultivar of snap bean according to update demands.
Codified Morphological Stage for Predicting Digestibility of Italian Ryegrass during the Spring Cycle
Authors: Valente Maria Eugenia , Borreani Giorgio , Peiretti Pier Giorgio , Tabacco Ernesto
Published: July 2010

A precise prediction of changes in digestibility of grasses during the growth cycle would allow targeting of harvests to desired levels of nutritive composition to meet specific animal requirements. In this study, regression analysis was used to formulate and test prediction equations for organic matter digestibility (OMD) of standing crops of Italian ryegrass (Lolium multiflorum Lam.) with codified morphological stage, canopy age, growing degree days (GDD), and N fertilization as independent variables. The field study was conducted for 7 yr with six Italian ryegrass cultivars, diversified for ploidy and earliness, grown in the western Po Valley (Italy). Nitrogen fertilizer was applied at various rates as top dressing. Sequential harvesting from early vegetative to full flowering provided herbage samples varying in age and stage of development. The 0–400 classification system that was used to evaluate the morphological stage included four primary stages: vegetative, elongation, inflorescence emergence, and flowering. The OMD decreased from 928 to 576 g kg−1 OM, as the herbage aged. All cultivars responded in the same way during the whole growth cycle. Morphological stage was a better predictor of OMD than GDD or age in days, with a higher r2 (0.88) and a lower root mean square error (28.0 g kg−1 OM). Nitrogen fertilization slightly decreased digestibility. The developed equation tested on an independent set of farm scale data showed that this codified morphological stage system can provide a rapid and easy estimate of Italian ryegrass digestibility in the field.
A Comparison of Three Methods for Reducing Iron‐Deficiency Chlorosis in Soybean
Authors: Goos R. Jay , Johnson Brian E.
Published: July 2010

Iron‐deficiency chlorosis is common when soybean [Glycine max(L.) Merr.] is grown on calcareous soils. The objective of this study was to compare the relative effectiveness of cultivar selection, foliar sprays, and FeEDDHA seed treatment for reducing chlorosis and increasing the yield of soybean planted in 15‐cm rows. Three cultivars (‘Glacier’, ‘Council’, and ‘Traill’) were grown in a factorial combination with two levels of foliar spray (control vs. two FeEDTA sprays) and two levels of seed treatment (control vs. FeEDDHA seed treatment). The cultivars gave an expected chlorosis response, with Glacier being the most susceptible, and Traill being the most resistant. Foliar sprays significantly (P≤ 0.05) reduced chlorosis at two sites. Seed treatment with FeEDDHA did not reduce chlorosis although this treatment was effective in prior studies with soybean planted in 76‐cm rows. Iron treatments did not reduce the chlorosis scores of Glacier to the level of Council or Traill without Fe treatments. Seed yields were significantly different for cultivars at all sites. Averaged across sites and Fe treatments, the yields were 1361, 1913, and 2203 kg ha−1, for Glacier, Council, and Traill, respectively. Foliar sprays tended to increase the yield of Glacier at two sites and significantly increased the yield of all three cultivars at another site. The yield responses to foliar sprays, when obtained, were about 300 kg ha−1. FeEDDHA seed treatment did not increase seed yield. Cultivar selection remains the most practical control measure for Fe‐deficiency chlorosis of soybean grown in narrow rows.
Evaluation of the Presidedress Soil Nitrogen Test for No‐Tillage Maize Fertilized at Planting
Authors: Rozas Hernán Sainz , Echeverría Hernán E. , Studdert Guillermo A. , Domínguez Germán
Published: July 2010

Soil N transformations under no‐tillage (NT) could affect the utility of the presidedress soil nitrate test (PSNT), particularly where early season growing conditions are cool as in Balcarce, Argentina. The PSNT was evaluated for irrigated NT maize (Zea mays L.) with different N rates (Exp. 1) and for rainfed maize under NT and conventional tillage (CT) with different preceding crops and N rates (Exp. 2). In both experiments, N was surface broadcast as (NH2)2CO at planting. The reliability of the PSNT was evaluated when NH+4–N was determined and when samples were taken up to a 60‐cm depth in the first experiment. In this experiment, the relative yield (RY) was highly correlated (R2 = 0.61−0.86) with soil NO−3–N concentration (0–30 cm) at the six‐leaf stage (V6). The reliability (R2) did not improve when NH+4–N was determined or when sampling was done up to a 60‐cm depth. In the second experiment, there was a good relationship between the RY and NO−3–N concentration (0–30 cm) at V6 (R2 = 0.47), and the R2 value increased (R2 = 0.61) when the preceding crop was wheat (Triticum aestivum L.). Soil NO−3–N critical concentrations ranged between 17 and 27 mg kg−1 and were associated with a RY of 0.92 or higher in both experiments. The results of this study show that the PSNT can be used to evaluate preplant N applications as a complementary method to N budget in maize under different management practices.
Effects of Broiler Litter in an Irrigated, Double‐Cropped, Conservation‐Tilled Rotation
Authors: Gascho Gary J. , Hubbard Robert K. , Brenneman Timothy B. , Johnson Alva W. , Sumner Donald R. , Harris Glendon H.
Published: July 2010

Broiler production is increasing rapidly in the Southern Coastal Plain, and little research has been conducted to evaluate broiler litter applications on the sandy soils of the region. We conducted a 4‐yr field study to determine optimum rates of broiler litter, its economic value, changes in soil tests to a depth of 90 cm, and effects on pathogens and nematodes. Summer crops were cotton (Gossypium hirsutumL.), pearl millet [Pennisetum glaucum(L.) R. Br.] for grain, and peanut (Arachis hypogaeaL.). Winter crops were wheat (Triticum aesitivumL.) and oilseed canola (Brassica napusL.). Litter rates were 0, 4.5, 9.0, and 13.5 Mg ha−1for each crop. Litter application increased yields of cotton, pearl millet, wheat, and canola and decreased yield of peanut. Average crop value increase from application of a megagram of broiler litter was estimated to be $42 ha−1yr−1when the application was made to all crops and $68 ha−1yr−1when none was applied to peanut. The mean cost of applied litter was approximately $12 Mg−1. Surface soil P, K, Cu, Zn, and Mn were increased in direct relation to litter rate. Data indicate that it would be prudent to limit applications to about 4.5 Mg ha−1. Litter applications had little effect on soil nematodes, butRhizoctonialimb rot (Rhizoctonia solaniAG‐4) of peanut increased. Lodging of canola, due toSclerotiniaspp., was doubled by any application of broiler litter.
Upland Rice Response to Phosphorus Fertilization in Asia
Authors: George Thomas , Magbanua Roger , Roder Walter , Van Keer Koen , Trébuil Guy , Reoma Veronica
Published: July 2010

Upland rice (Oryza sativaL.) yields on infertile, acid soils in the Asian uplands average only 1 Mg ha−1Phosphorus deficiency is considered a major soil constraint to increased yield, but little quantitative information is available. We analyzed P responses of traditional rice on farm in Laos, Thailand, and the Philippines and improved varieties in researcher‐managed trials in the Philippines. Treatments in on‐farm trials were a control and 50 kg P ha−1± 100 and 50 kg ha−1N and K, respectively. Treatments in researcher‐managed trials were P rates on an unlimed and limed Ultisol. Mehlich‐1 extractable P correlated with on‐farm grain yield (r= 0.47). Phosphorus fertilization increased average grain yield (1 Mg ha−1) by 20%, total biomass (4 Mg ha−1) by 27%, and P uptake (4.1 kg ha−1) by 53%. Yield increased 37% with P + N + K, but only 16% of the 2.4 Mg ha−1biomass increase was grain. Improved rice in researcher‐managed trials responded to P, with a larger proportion of biomass partitioned to grain [i.e., higher harvest index (HI)]. Grain yield of ‘UPLRi‐5’ increased from 3.2 to 4.6 Mg ha−1in limed soil while that of ‘IR55423–01’ increased from 3.4 to 4.0 Mg ha−1in unlimed soil. Phosphorus fertilization always increased the frequency of higher yields averaged across trials, soils, varieties, and growing conditions. Yield gain from on‐farm P fertilization of traditional rice was small because of low HI, unlike in improved varieties, which had a HI. We infer that increasing upland rice yield in Asia would require genotypes with higher HI in addition to P fertilization.
Yield and Growth Components of Potato and Wheat under Organic Nitrogen Management
Authors: van Delden Arnout
Published: July 2010

In order to optimize N management in organic farming systems, knowledge of crop growth processes in relation to N limitation is necessary. The present paper examines the response of potato (Solanum tuberosum L.) and wheat (Triticum aestivum L.) to N with respect to intercepted photosynthetically active radiation (PAR), light use efficiency (LUE), and leaf N concentration ([N]). Potato and wheat cultivars were grown in field experiments (1997 and 1998) at three N levels: no N (N1), cattle (Bos taurus) slurry (N2), and cattle slurry supplemented by mineral N fertilizers (N3). Estimated available N from the soil (0–0.9 m) plus added fertilizer was 80 (N1), 150 (N2), and 320 (N3) kg ha−1 for potato and 115 (N1), 160 (N2), and 230 (N3) kg ha−1 for wheat. Nitrogen deficiency was quantified by an N nutrition index (NNI; 1 = hardly limited, 0 = severely limited). Nitrogen deficiency increased in the N1 and N2 treatments up to 20 (potato) and 50 (wheat) d after emergence, with small changes thereafter. An increasing N limitation in potato (NNI = 1–0.55) resulted in a linear decrease in crop dry weight and cumulative intercepted PAR and in a linear increase of the harvest index, whereas the LUE decreased only at NNI values below 0.65. Crop dry weight and cumulative intercepted PAR for wheat decreased linearly with N limitation (NNI = 0.9–0.6), but the harvest index and LUE were unaffected. For both crops, N limitation to 0.55 caused a linear decrease in maximum leaf area index, the rate of foliar expansion, leaf area duration, and to a lesser extent, leaf [N]. In conclusion, both crops respond to N limitation by reducing light interception while maximizing the LUE and leaf [N].
Potassium Fertilization Effects on Alfalfa in a Mediterranean Climate
Authors: Lloveras Jaime , Ferran Javier , Boixadera Jaime , Bonet Jordi
Published: July 2010

Potassium fertilization rates for alfalfa (Medicago sativa L.) have been increasing with intensive cropping systems or decreasing with policies that generally lead to reduced fertilizer inputs. In this case, nutrient buildup or maintenance of high soil test levels may not be desirable and drawdown of K reserves may be beneficial in the short term. The objective of this research was to evaluate the effects of potassium fertilization of alfalfa in areas of high soil exchangeable K levels and long growing seasons. A field experiment was established under irrigation from 1993 to 1997 in the Mediterranean environment of the Ebro Valley (Spain) on a silty clay loam soil. The treatments were five annual rates of K (0, 41.5, 83, 166, and 332 kg K ha−1) and two rates of K (166 and 332 kg K ha−1) applied prior to seeding on two alfalfa cultivars. The average annual dry matter (DM) yield was 21.5 Mg ha−1 and showed a small linear response to K fertilization (Pr > F = 0.0589). Total K removal in the herbage increased linearly with each rate of K and reached 1728 kg K ha−1 with the application of 332 kg K ha−1 yr−1, compared with 1546 kg K ha−1 without K fertilization. At the end of the experiment, soil ammonium acetate extractable K (Ke) increased little with K rates, and the differences were observed only in the first 30 cm of depth. Despite the uptake of 1546 kg K ha−1, soil Ke values did not change appreciably, suggesting that much of the K uptake was derived from the fertilizer and from nonexchangeable soil K fractions. Although K fertilization slightly increased alfalfa DM yields in this high testing Mediterranean soil, the economic benefit of this limited response does not justify the expense.
Mineral Composition of Swards Containing Forage Chicory
Authors: Belesky David P. , Turner Kenneth E. , Fedders J. M. , Ruckle Joyce M.
Published: July 2010

Chicory (Cichorium intybusL.), a highly productive forage under midsummer conditions in the eastern USA, often has higher concentrations of minerals relative to grasses and legumes. Low concentrations of minerals in herbage could reduce production efficiency or create metabolic disorders in livestock. Information on the mineral composition of chicory is limited, but it is needed to improve our understanding of nutritive value and inputs required to sustain chicory production, especially where high rates of N are applied. We conducted field experiments for 3 yr on a Ramsey soil (Loamy, siliceous, subactive, mesic Lithic Dystrudept) in southern West Virginia to determine (i) response to increasing fertilizer N and (ii) production of chicory as a component of swards, including grass and legume as a function of clipping frequency. Mineral concentrations and uptake in available herbage generally increased as N rate increased and were influenced by the botanical composition of the sward. As chicory content decreased in the sward, so did mineral concentrations and uptake. Changes in sward composition associated with chicory influenced important mineral ratios such as N/S, Ca/P, and K/(Ca + Mg) cation equivalent ratio that have significant bearing on livestock health and production efficiency. Clipping frequency and N inputs influenced chicory persistence and ultimately the mineral composition of the sward. Active accumulation of minerals indicates the need for high nutrient input to sustain production, especially on soils with marginal fertility. Health problems associated with mineral nutrient concentrations probably would be minimal in livestock grazing swards that include chicory.
Subsurface Drain Losses of Water and Nitrate following Conversion of Perennials to Row Crops
Authors: Huggins David R. , Randall Gyles W. , Russelle Michael P.
Published: July 2010

Nitrate losses through subsurface drains in agricultural fields pose a serious threat to surface water quality. Substantial reductions in drainage losses of NO3–N can occur with alfalfa (Medicago sativa L.) or perennial grasses as used in Conservation Reserve Program (CRP) plantings. Conversion of perennials to annual row crops, however, could have rapid, adverse affects on water quality. We evaluated water and N use efficiency of row crops following perennials, and losses of water and NO3–N to subsurface drains. Four cropping systems: continuous corn (Zea mays L.), a corn–soybean [Glycine max (L.) Merr.] rotation, alfalfa (ALF), and CRP, were established in 1988. The ALF and CRP were converted to a corn–corn–soybean sequence from 1994 through 1996 while continuous corn (C‐C) and corn–soybean (C‐S) rotations were maintained. Following CRP, corn yield was 14% and water use efficiency (WUE) 20% greater as compared with C‐C. Yield was 19% and WUE 21% greater for soybean following corn in CRP and ALF as compared with C‐S. Residual soil NO3–N (RSN) increased 125% in first year corn following CRP and was 32% greater than C‐C by 1996. High N uptake efficiencies of corn following alfalfa slowed the buildup of RSN, but levels were equal to row crop systems after 2 yr. Nitrate losses in drainage water remained low during the initial year of conversion, but were similar to row crop systems during the subsequent 2 yr. Beneficial effects of perennials on subsurface drainage characteristics were largely negated following 1 to 2 yr of corn.
Irrigated Wheat Grazing and Tillage Effects on Subsequent Dryland Grain Sorghum Production
Authors: Winter Steven R. , Unger Paul W.
Published: July 2010

Use of conservation tillage has improved sorghum [Sorghum bicolor (L.) Moench] grain yield 10 to 20% in ungrazed wheat (Triticum aestivum L.)–fallow–sorghum production systems. Our objective in this 2‐yr field study was to develop tillage guidelines for systems where the wheat was grazed. Grazing duration on winter wheat and tillage during the fallow period preceding dryland grain sorghum were treatments on Pullman clay loam (Torrertic Paleustoll). Grazing increased surface soil compaction and reduced wheat residues. Surface soil (0–5 cm) penetration resistance was 0.36, 0.52, 0.75, and 0.92 Mpa, and wheat residue in 1996 was 6.0, 4.8, 3.5, and 1.2 Mg ha for ungrazed and early, normal, and late cattle removal dates, respectively. As a result, sorghum grain yield in 1996, an exceptionally wet season, was 7.9, 7.5, 7.0, and 3.8 Mg ha−1, respectively, with no tillage (NT). In 1997, a dry season with low runoff, only the late cattle removal with NT had reduced yield (3.4 Mg ha−1 compared with 3.9 Mg ha−1 for ungrazed NT). Use of one‐time sweep tillage early in fallow resulted in an increase in sorghum grain yield of 1.9 Mg ha−1 in 1996 for the late cattle removal treatment compared with NT, but it had no effect on yield with the normal cattle removal treatment. In 1997, one‐time sweep tillage increased yield by 0.3 Mg ha−1 with late removal. When wheat residue was ≤2.4 Mg ha−1 following grazing, sweep tillage reduced surface compaction, increased soil water at planting an average of 26 mm over 2 yr, and improved grain yield of sorghum compared with NT. If wheat residues were ≥3.5 Mg ha−1 after grazing, NT was as effective as any tillage treatment. Results agree with conservation tillage guidelines developed on ungrazed wheat.
Tillage and Pest Management Considerations in a Peanut–Cotton Rotation in the Southeastern Coastal Plain
Authors: Johnson W. Carroll , Brenneman Timothy B. , Baker Shelby H. , Johnson Alva W. , Sumner Donald R. , Mullinix Benjamin G.
Published: July 2010

Radical changes in crop production have occurred in the southeastern USA in recent years. Peanut (Arachis hypogaea L.) and cotton (Gossypium hirsutum L.) are now planted in direct rotation, and conservation tillage is commonly used for both crops. Comprehensive data is lacking on crop and pest management recommendations in those systems, so a long‐term study was conducted in Tifton, GA on the effects of tillage systems on crop and pest management in a peanut–cotton rotation. Systems evaluated were conventional, reduced, and minimum tillage. Plots in conventional tillage systems were harrowed, deep‐turned, and planted each year. In reduced tillage systems, plots were harrowed in the fall and planted to rye (Secale cereale L.), and crops were planted into killed rye. In minimum tillage systems, plots were neither tilled nor planted to rye and remained nontilled during the winter, and crops were planted directly into the previous crop stubble. Weed control was based on species present and tillage system. Peanut was either treated with flutolanil [3′‐isopropoxy‐2‐(trifluoromethyl) benzanilide] for soil‐borne disease control or not treated (control). Yields were sustained for 5 yr with no difference in peanut or cotton yields among tillage systems. Flutolanil controlled soil‐borne diseases and increased peanut yields, working equally well in all three tillage systems. Weed densities and species composition changed, causing more intensive and costly weed control in reduced and minimum tillage systems than in conventional tillage systems. Spotted wilt (tomato spotted wilt tospovirus) incidence was 42% lower in reduced and minimum tillage systems than in conventional tillage systems and is now part of the recommended strategy to manage the disease.
Characterization and Utilization of Nitrogen Contained in Sweet Corn Silage Waste
Authors: Fritz Vincent A. , Randall Gyles W. , Rosen Carl J.
Published: July 2010

Sweet corn (Zea maysL. var.rugosaBonaf.) silage waste (SCSW), a byproduct of the vegetable processing industry, accounts for 61 to 73% of the initial harvest yield. Concern relating to land application of SCSW has focused on the potential environmental impact of large quantities of mineralized N from the waste. This study was conducted to quantify the rate and amount of N mineralization from varying rates of SCSW applied to a fine‐textured glacial till soil and to determine if nutrient contributions from SCSW can be integrated into a nutrient management system for subsequent crop production while enhancing environmental stewardship. Sweet corn silage waste was land‐applied to main plots at rates of 0, 112, 224, 336, and 448 t ha−1(fresh wt.) to a harvested sweet corn field and moldboard‐plowed in early fall. Urea [(NH2)2CO] was preplant broadcast‐applied and incorporated to subplots at rates of 0, 67, and 134 kg N ha−1in 1993; and 0, 83, and 166 kg N ha−1in 1994 and 1995. Mineralization of N in the SCSW was assessed by NO3–N analysis of in‐season and postharvest soil samples and by yield and N uptake of field corn. Spring temperature and precipitation greatly influenced mineralization of SCSW. In the wet, cold year, in‐season NO3–N concentrations were lower and postharvest NO3–N was not affected by SCSW rate. Grain yield and N uptake were increased with increasing SCSW rate. In the warmer and drier years, in‐season and postharvest NO3–N concentrations were much greater and were significantly increased by increasing SCSW rates. Corn grain yield and N uptake were optimized by a combination of SCSW and fertilizer N when SCSW rates were <224 t ha−1. At rates >224 t ha−1, mineralized N from the SCSW was sufficient to maximize yields. Nitrogen availability in the first year after SCSW application averaged about 16 to 18% of the total SCSW‐N applied. Averaged across the 3 yr, soil test P was increased 2.6 mg kg−1with each 112 t ha−1SCSW rate, whereas soil test K was increased 14.2 mg kg−1by each 112 t ha−1SCSW rate. Land application of up to 224 t ha−1SCSW was feasible, provided it was given the appropriate N credit before supplementing with N fertilizer.
Selecting the High‐Yield Subpopulation for Diagnosing Nutrient Imbalance in Crops
Authors: Khiari Lotfi , Parent Léon-Étienne , Tremblay Nicolas
Published: July 2010

Plant nutrient status is currently diagnosed using empirically derived nutrient norms from an arbitrarily defined high‐yield subpopulation above a quantitative yield target. Generic models can assist Compositional Nutrient Diagnosis (CND) in providing a yield cutoff value between low‐ and high‐yield subpopulations for small databases. Our objective was to compute the minimum yield target for sweet corn (Zea mays L.) and the corresponding critical CND nutrient imbalance index using a cumulative variance ratio function and the chi‐square distribution function. Population (40 observations) and validation (20 observations) data were selected at random from a survey database of 240 observations including commercial yields and leaf nutrient concentrations. A filling value (Rd) was computed as the difference between 100% and the sum of d nutrient proportions [Rd = 100 − (N + P + K + …)]. The CND nutrient expressions were the row‐centered ratios of N, P, and Rd proportions in tissue specimens. Variance ratio computations of CND nutrient expressions among two subpopulations arranged in a decreasing yield order were iterated across population data. The proportion of low‐yield subpopulation computed at the inflection point of a cubic cumulative variance ratio function was 67.5%, the minimum proportion of low‐yield specimens. That exact probability corresponded to a theoretical chi‐square value (CND r2) of 1.5 for three components. The critical CND r2 value was validated using independent samples and the sum of the squared CND nutrient indices. The procedure is applicable to small‐size crop nutrient databases for solving nutrient imbalance problems in specific agroecosystems. A calculation example is presented.
The Phosphorus Compositional Nutrient Diagnosis Range for Potato
Authors: Khiari Lotfi , Parent Léon-Étienne , Tremblay Nicolas
Published: July 2010

Leaf analysis could assist in adjusting the P fertilization of potato (Solanum tuberosumL.) to specific soil–plant systems to achieve high yield conditions. Our objective was to derive and validate Compositional Nutrient Diagnosis (CND) norms and ranges for a potato cultivar (Superior) and to compare CND to Diagnosis and Recommendation Integrated System (DRIS) and the Critical Value Approach (CVA). Survey data were obtained from 563 field observations and validated using 100 independent samples and across four P fertilizer trials. The databases included tuber yield and analyses (N, P, K, Ca, and Mg) of the upper fully expanded leaf collected at beginning of bloom. Yield cutoff between low‐ and high‐yield subpopulations, selected from cumulative variance functions across survey data, was 34.1 Mg ha−1. The sum of squared values of CND indexes was distributed like a chi‐square value. The critical chi‐square value was 4.2. The critical CND P index range was between −0.80 and 0.80. Similar critical values were obtained for the validation population and fertilizer trials. The CND P index appeared symmetrical about the zero nutrient balance and was more closely related to yield compared with DRIS and CVA. The CND provides an inferential (as chi‐square) and symmetrical (about zero balance) diagnosis at low cost, could provide nutrient index ranges adjusted to yield goal, and could thus be developed advantageously for specific soil–plant systems.