Nutrient-rich biochar produced from animal wastes, such as poultry litter, may increase plant growth and nutrient uptake although the role of direct and indirect mechanisms, such as stimulation of the activity of mycorrhizal fungi and plant infection, remains unclear. The effects of poultry litter biochar in combination with fertilizer on mycorrhizal infection, soil nutrient availability and corn (Zea mays L.) growth were investigated by growing corn in a loam soil in a greenhouse with biochar (0, 5 and 10 Mg/ha) and nitrogen (N) and phosphorus (P) fertilizer (0, half and full rates). Biochar did not affect microbial biomass C or N, mycorrhizal infection, or alkaline phosphomonoesterase activities, but acid phosphomonoesterase activities, water-soluble P, Mehlich-3 Mg, plant height, aboveground and root biomass, and root diameter were greater with 10 Mg/ha than with no biochar. Root length, volume, root tips and surface area were greatest in the fully fertilized soil receiving 10 Mg/ha biochar compared to all other treatments. The 10 Mg/ha biochar application may have improved plant access to soil nutrients by promoting plant growth and root structural features, rather than by enhancing mycorrhizal infection rates.

Soybean [Glycine max (L.) Meal growers in the midsouth United States have increasingly practiced early planting and doublecropping systems. Information on crop management is desired by soybean growers to improve production and profitability. Effects of irrigation and planting date on seed yield and other agronomic traits were investigated in soybean cultivars from eight maturity groups (MG) in 2002 and 2003 at two locations in Arkansas. The planting date (April, May, and June) and irrigation treatments significantly affected seed yield, plant height, and maturity. Significant effects were also observed for number of nodes, number of pods, and number of seeds per plant, whereas number of branches per plant was not affected by planting date and irrigation treatments. Irrigation improved seed yield by an average of 83% (986 kg/ha) in all experiments conducted across two years. Highest seed yield was achieved when soybeans were planted in May, followed by April and then by June planting. The MG V and VI cultivars, conventionally grown in Arkansas, produced higher seed yields than other maturity groups and were the most suitable cultivar selections when considering seed yield alone. Significant interactions were observed among planting date, irrigation, and maturity groups/genotypes. The MG IV was a better candidate for the double-cropping system (June-planting) because of its earlier maturity and high seed yield. For the early soybean production system (April-planting), MG I and II cultivars were potentially good selections because of their short growing periods and acceptable seed yields. The various planting dates and irrigation systems combined with proper cultivar selections provide soybean producers with more options for using the land and water efficiently.

Information is lacking in soybean [Glycine max (L) Merr.] on whether or not variety selection and management practices can improve seed quality in early production systems. Effects of planting date, irrigation, genotype and maturity on seed quality traits in soybean were investigated in Arkansas for two years. Irrigation (I), planting dates (PD), and maturity groups/genotypes (MG/G) significantly affected seed quality traits. The MG/G, followed by I and PD treatments, made the largest contribution to variations in seed quality traits. Irrigation and late planting significantly improved seed standard and cold germination for most maturity groups. Irrigation also tended to increase seed protein content, whereas planting dates had no impact on seed protein and oil content. Both irrigation and planting dates had little or no effect on visual seed quality and seed pathogen infection. Maturity group and genotype significantly affected all seed quality traits. Late-maturing genotypes exhibited significantly higher standard and cold germination rate, fewer pathogen-infected seed, and better visual seed quality than early-maturing genotypes. Wide-row spacing improved seed germination. Seed germination and vigor of early-maturing genotypes decreased, whereas those of late-maturity genotypes improved when planting was delayed from April to June. Early-maturing genotypes were more responsive to irrigation when planted late. Significant correlation was found between cold and standard germination with other seed quality traits, including visual seed quality rating, disease-free seeds, and Phomopsis-infected seeds. We demonstrated that variety selection and irrigation were important in achieving high seed quality of early-maturing soybeans.

Due to the popularity of double-crop production systems in the southern United States, particularly soybean [Glycine max (L.) Merrill] following wheat (Triticum aestivum L.), wheat-residue management practices are critical to the successful establishment of double-cropped soybean. The objective of this study was to ascertain the effects of N application to wheat on no-tillage soybean growth and production in a double-crop system. This study was conducted over two cropping seasons at two locations on silt-loam Alfisols in eastern Arkansas. Wheat grain yield and subsequent residue mass generally increased as total applied N increased. Soybean plant population, height, and growth-stage rating approximately 30 days after planting were generally unaffected by total applied N to wheat or wheat-residue level. These results indicate that there is no negative impact to soybean planted without prior tillage into a wide range of wheat-residue levels and demonstrates that technological advancements with field implements have been able to overcome the concern of planting into high-residue situations.

Approximately 25% of the soybean [Glycine max (L.) Merr.] grown in the mid-South is produced in a wheat (Triticum aestivum L.)-soybean double-crop system. Pre-soybean field preparations often consist of removing wheat residue by burning followed by conventional tillage (CT). However, crop residue burning has serious negative environmental consequences and will likely be outlawed in the future. Therefore, the objective of this study was to evaluate the short-term effects of alternative wheat-residue management practices, tillage [no-tillage (NT) and CT], burning (burn and no burn), and wheat-residue level (low and high), on soil surface properties after two full cropping cycles in a wheat-soybean double-crop production system on two silt-loam Alfisols in east-central Arkansas. Soil bulk density increased over time, but the increase was unaffected by imposed treatments. Changes in soil pH and electrical conductivity (EC) were generally unaffected by tillage or burning, whereas soil EC increased by 7% under the high and decreased by 8% under the low wheat-residue level treatment at one location, but not the other. Mehlich-3-extractable Mg and Zn increased more and Na decreased less under NT than CT at one location or the other. Soil organic matter and total N and C also increased more under NT than CT at one location, but not the other. The results of this study indicate that, in a wheat-soybean double-crop production system in a relatively warm and wet environment, numerous soil properties can be improved more under NT than CT and more when crop residues are left unburned than when they are removed by burning. Extended use of alternative wheat-residue management practices that improve soil tilth will result in more sustainable agriculture and likely increase production.

Producers control crop fertilization practices. If the amount of grain yield per unit of aboveground biomass produced can be optimized with proper fertilization, nongrain aboveground biomass will be minimized. Achieving this goal would be especially beneficial in a wheat (Triticum aestivum L.) and soybean (Glycine mar L.) double-crop production system where proper fertilization could promote a residue-management shift from burning and conventional tillage to a conservation or no-tillage system. The objectives of this study were to i) determine the effect of nitrogen (N) rate on wheat yield, aboveground biomass, and partial harvest index (PHI), and ii) identify an appropriate predictive response model for wheat yield and PHI as a function of total N applied under low phosphorus (P) and potassium (K) fertility. This study was conducted over two cropping seasons at two locations on similar silt-loam Fragiudalfs in eastern Arkansas where wheat was fertilized at 10 N rates ranging from 0 to 10 1 kg N ha(-1) applied once at the early-jointing stage and from 151 to 269 kg N ha-1 applied in a split application at the early-jointing stage and at the late-jointing stage as depicted in the Feekes staging method. The effects of N fertilization on wheat growth and production varied somewhat between locations and from one year to the next. However, the current N recommendation for wheat in Arkansas (i.e., a single application of 101 kg N ha(-1)) appears to be too low to produce maximum yields under low P and K. fertility. Differing yield responses between locations were likely due to the combination of inherent P and K fertility differences and carryover N from the previous crop during the first year of the study. Capitalizing on the relationship among N rate, grain yield, and PHI will allow wheat producers to minimize N applications and production of excessive aboveground biomass, while still being able to produce an economically viable yield.

ABSTRACT Double-cropping wheat (Triticum aestivum L.) and soybean [Glycine max (L.) Merr.] is popular throughout the mid-southern United States. To ensure an adequate stand, it is imperative that soybean be planted as soon as possible after wheat harvest due to an already shortened growing season following wheat. Typically, wheat residue is burned, and then conventional tillage (CT) is used to prepare a seedbed for soybean planting. However, residue burning has serious negative environmental consequences. The objective of this study was to examine effects of tillage [CT and no-tillage (NT)], residue burning (burn and no burn), and wheat-residue level (high and low) on soybean stand establishment, growth, and production over three cropping cycles at two locations on silt-loam Alfisols in eastern Arkansas. Soybean plant populations between 10 and 30 days after planting were higher (p < 0.02) under NT than CT in most year-location combinations, while most without wheat residue burning were equivalent to those with burning. Soybean plant populations were unaffected by N rate/wheat-residue level in most year-location combinations. Mid-season soybean leaf area index was higher (p < 0.03) under NT than CT for two of four year-location combinations. Soybean yields under NT were equivalent to yields under CT in all year-location combinations. Results indicate that the alternative pre-plant field preparation combination of no residue burning followed by NT can perform as well as the more traditional combination of burning followed by CT in the wheat-soybean double-crop system in the mid-southern United States.

Many eastern Arkansas producers who typically grow soybean (Glycine max L.) in a wheat (Triticum aestivum L.)-soybean double-crop system choose to burn wheat residue immediately after harvest as a means of seedbed preparation. Burning residue adds a considerable amount of carbon dioxide (CO2) to the atmosphere and prevents the return of much needed carbon (C) to the soil. Alternative wheat-residue management practices have the potential to be as, if not more, environmentally sound, economical, time-efficient, and productive as the traditional practice of burning wheat residue prior to growing a soybean crop. Alternative wheatresidue management practices may also improve the quality of the soil resource in the delta region of eastern Arkansas.

Seven tall-growing soybean (Glycine max [L.] Merr.) lines, including the cultivars Derry, Donegal, and Tyrone plus the experimental lines OR 5-12-1T, OR 13-12-3, OR 19-12-2, and PA 5-2-1, were harvested, ensiled, and tested for nutritive quality to evaluate the potential of these lines as silage crops. Tall-growing (or forage) soybeans were compared with a grain-type Group V soybean (Hutcheson) and forage sorghum (Sorghum bicolor [L.] Moench) (Pioneer 838 F). Lines were replicated four times at sites near Fayetteville and Rohwer, Arkansas in 1995 and 1996, harvested at full seed (soybean growth stage R-6), and ensiled for 33 d. Derry, Donegal, and Tyrone produced average DM yields for both years of 5,216, 7,118, and 6,900 kg/ha at Fayetteville and 6,738, 6,398, and 6,300 kg/ha at Rohwer, respectively. The tallest entries grown in Fayetteville were Tyrone and OR 13-12-3; Derry was tallest at Rohwer. Average concentrations of NDF, ADF, CP, and IVDMD in silage from Derry, Donegal, and Tyrone were 41.8, 43.9, and 43.1%; 33.0, 33.6, and 33.2%; 12.6, 14.2, and 14.0%; and 70.4, 72.1, and 70.6%, respectively, at Fayetteville and 47.4, 49.0, and 43.1%; 33.9, 37.0, and 31.3%; 13.8, 16.0, and 13.7%; and 63.0, 66.8, and 62.5%, respectively, at Rohwer when averaged over both years. Silage for all lines was well preserved as indicated by the low final pH and a high lactic acid concentration. Of the forage soybean lines tested, PA-5-2-1 and Donegal had consistently higher nutritive values at both locations for 2 consecutive yr.

There are roughly 220 golf courses in Arkansas, and as many as 50% of these courses were constructed using common bermudagrass fairways. Although resilient, common bermudagrass loses density and quality over time. In this experiment physical and chemical properties of the soil were analyzed to determine the causes of decline in turf quality observed on several fairways of a local golf course. Once a particular fairway was selected for study and preliminary soil sampling conducted, GS+, a geostatistical computer program, was used to map the location of certain chemical deficiencies. A moderate to severe Mg deficiency was detected throughout the fairway. Twelve different fertility treatments were designed to enhance the overall density, texture, and color of the turf. Magnesium sulfate (MgSO4), Primo™ (a plant growth regulator), and Nitron (an organic nitrogen source) all showed significant improvements in turf quality. Extensive and comprehensive soil testing was found to be very beneficial; “hidden” nutrient deficiencies were discovered, which allowed site-specific treatments to be included in the test.

Accurate predictions of forage quality of winter wheat (Triticum aestivum L.) during spring would allow targeting of harvests or grazings to desired levels of nutritive composition to meet specific animal requirements. The objectives of this study were to compare number of days since 15 February (DAYS) and growing degree days (GDD, base 4.4-degrees-C) as predictors of Feekes and Zadoks growth stages, and to compare DAYS, GDD, Feekes, and Zadoks growth stages as predictors of forage yield and quality. The 2-yr study on a Captina silt loam (fine, mixed, mesic, Typic Fragiudult) at the University of Arkansas Main Experiment Station, Fayetteville, AR, involved four cultivars of soft red winter wheat. Plots were harvested at six growth stages: beginning of pseudostem elongation, second node detectable, flag leaf collar just visible, boot swollen, inflorescence completely emerged, and soft dough. Feekes and Zadoks growth stage scales were regressed on DAYS and GDD. Forage yield, percentage lamina (ratio of leaf lamina to whole-plant dry weight), and nutritive concentrations were regressed on Feekes, Zadoks, DAYS, and GDD. Lower root error mean squares were generally obtained with GDD than DAYS for predicting growth stages. Zadoks scale and DAYS were generally the best predictors of forage yield, whereas Feekes scale and DAYS were the best predictors of percentage lamina and crude protein. Zadoks and GDD were the best predictors of neutral detergent fiber and in vitro dry matter digestibility. The Zadoks scale and GDD would be useful parameters in wheat growth models designed to target harvests to desired levels of forage quality.

Our objectives were to compare wheat and wheat-ryegrass mixtures for patterns of DM accumulation and forage quality changes with maturity. Two genotypes of soft red winter wheat (‘Magnum’ and the hybrid ‘HW 3015’) were grown alone or in mixture with ‘Marshall’ annual ryegrass. Plots were harvested at six wheat growth stages from beginning of pseudostem elongation to soft dough. Handclipped samples were separated into species and leaf and stem (including inflorescence) components, and the components were analyzed for NDF and in vitro DM disappearance. Annual ryegrass in mixture with wheat did not enhance the forage yield over wheat alone; however, the later maturity of ryegrass in relation to wheat resulted in a slower decline in total mixture leaf proportion with advancing maturity than in wheat alone. Enhanced leafiness did not, however, augment total mixture in vitro DM disappearance over that of wheat alone because of the low in vitro DM disappearance of ryegrass stems. If wheat is to be grown for harvest at the soft dough stage for forage, it should not be grown with annual ryegrass, because the latter dilutes the high quality, wheat grain portion with low quality ryegrass stems.

The cultivation and evaluation of the grain amaranths Amaranthus hypochondriacus and Amaranthus cruentus as potential field crops has been initiated by several investigators worldwide. Because of their similarity to the grain amaranths, the pigweeds ( Amaranthus spp.) represent a potential weed-control problem. To date, no research on chemical weed control in grain amaranth has been reported. Greenhouse herbicide screening studies were conducted on a Captina silt loam soil (fine-silty, siliceous, mesic Typic Fragiudults) to evaluate herbicide selectivity for control of smooth pigweed ( Amaranthus hybridus L.) and Palmer amaranth ( Amaranthus palmeri S. Wats.) without injury to the grain amaranths. Of the herbicides tested, bentazon [3-(1-methylethyl)-1 H -2,1,3-benzothiadiazin-4(3 H )-one 2,2-dioxide], naptalam [2-[(1-naphthalenyl-amino)carbonyl]benzoic acid} + dinoseb [2-( sec butyl)-4,6-dinitrophenol], and metolachlor [2-chloro- N -(2-ethyl-6-methylphenyl)- N -(2-methoxy-1-methylethyl) acetamide] exhibited a degree of selectivity towards A. cruentus or A. hypochondriacus . These findings offer encouragement for further studies on the effects of rates and time of application on herbicide selectivity for grain amaranths.

Seed from two species of amaranth (Amaranthus cruentus and A. hypochondriacus) were incorporated into diets at 20 and 40% in raw and autoclaved form. Weight gains of chickens fed diets with 20% amaranth did not differ significantly from that of chickens fed a corn-soybean meal control diet, whether grain was fed raw or autoclaved. Feed intake was reduced slightly at this level of inclusion. Weight gains and feed intake of chickens fed diets containing 40% amaranth were significantly reduced. Reduction in performance was more severe in chickens fed hypochondriacus species and was partially alleviated by autoclaving. Results indicate that amaranth grain may be utilized by broiler chickens, but further work is necessary to determine means to overcome growth depression associated with higher usage levels and to assess possible species differences.