Terry C. Keisling

Winter cover crops influence on cotton yield and selected soil properties

Abstract Winter cover crop studies were conducted for 17 years with cotton grown on a Dubbs‐Dundee soil complex at the University of Arkansas Delta Branch Experiment Station. This experiment was established in 1972 to investigate the changes induced by winter cover crops of rye, vetch, and lupine. The rye and lupine were later changed to rye + vetch and rye + crimson clover, resp. Cotton yield responses to cover crops were found to be highly dependent on the growing season. Although the cover crops averaged a seedcotton yield increase, certain years had drastic yield reductions. This experiment was not designed with sufficient scope to address why yield responses occurred as they did. Soil physical properties of hydraulic conductivity, water retention, porosity, and proportion of large pores were found to be measurable changed by having winter cover crops. In general the change in soil physical properties resulting from the cover crops would result in faster infiltration and transmission of water, more st...

Visual symptoms and tissue manganese concentrations associated with manganese toxicity in wheat

Abstract Wheat (Triticum aestivum L.) was grown in nutrient solution in the greenhouse. Mn concentrations in the nutrient solutions used ranged from 0.0025 to 50,000 mg/1. Visual symptoms associated with high tissue Mn content were stunting, general chlorosis, necrotic leaf spots, white flecking, purpling, and leaf tip burn. Mn tissue concentrations of 380 mg/kg were found to reduce dry matter production by 10%.

Using cotton petiole nitrate‐nitrogen concentration for prediction of cotton nitrogen nutritional status on a clayey soil 1

Abstract Soil and petiole nitrate‐nitrogen (NO3‐N) analyses have been used to monitor the nitrogen (N) nutritional status of cotton (Gossypium hirsutum L.) in Arkansas. The basis for in‐season N fertilizer additions has been NO3‐N monitoring for the most recently matured leaf petiole. In this manner N fertilizer can be adjusted so that N is not limiting during growing seasons conducive to high yields. The objective of studies reported herein was to determine petiole NO3‐N levels that define deficient, adequate, and excessive N nutritional status of irrigated cotton growing on a clayey soil. Experiments were conducted on a Sharkey silty clay (very fine, montmorillonitic, nonacid, thermic, Vertic Haplaquept) located on the Northeast Research and Extension Center at Keiser, AR. The experimental design was a 5 by 5 Latin Square with a split plot arrangement of treatments. Subplots were cultivars of cotton, and main plots were N rates of 0, 56, 112, 168, and 224 kg/ha applied as 56 kg/ha splits beginning just ...

Selection for ryegrass genotypes with tolerance to aluminum toxicity

Abstract This study reports on a procedure where ryegrass (Lolium multiflorum Lam.) varieties are screened for tolerance to aluminum toxicity. The procedure utilized was a solution‐paper method where seedlings were grown on filter paper which transported nutrient solution from a reservoir. Mean root length for genotypes was the character utilized to determine tolerance to aluminum toxicity. Ryegrass genotypes were subjected to [Al] between 0 to 8 mM with the most useful concenrations being from 2 to 4 mM. Genotypes which demonstrated some tolerance to higher [Al] were North American Plant Breeders R. 0051, ‘Aubade’, ‘Urbana’, Fla 1977B, ‘Tetragulf, Mommersteeg Lmw 96. Considerable variation in root length due to genotypic effect tended to obscure the [Al] effect. The relative rankings of root growth ratios of 4 mM [Al] to 2 mM [Al] tolerance of ryegrass cultivars is questionable. Further work to establish a more reliable screening technique for this specie needs to be undertaken.

TWO METHODS OF COMPOSTING GIN TRASH

The ginning of cotton (Gossypium hirsutum L.) results in the accumulation of approximately 90 kg of gin trash per bale of cotton ginned. In the past, disposal of raw gin trash was by burning, land application and feeding to livestock, but problems with clean air standards, weed seeds and diseases, and chemical residues, respectively, make each of these methods unacceptable. Composting the gin trash would alleviate certain problems associated with land application on farm fields. Experiments were conducted to investigate windrow composting. A split plot experiment with five reps was initiated to evaluate turning times, nitrogen (N) fertilization and bacterial inoculation. Composite samples were collected and analyzed for nutrients and selected chemicals. Another experiment was established to compare timing and physical methods of turning windrows. The Lipsey®-gin-trash-composting system was investigated by sampling three compost piles at three different cotton gins. The chemical composition and weed seed germination were investigated. Results indicate that windrow composting does not solve the weed seed or plant disease problem; otherwise, the product was satisfactory. The Lipsey®-gin-trash-composting system resulted in a pile of material whose outside 0 to 15 cm depths contained viable weed seeds and disease organisms, but none survived below this exterior. This system resulted in an incomplete composting material with offensive odors.

Calcium level in the peanut fruiting zone as influenced by gypsum particle size and application rate and time

Abstract The peanut requires a readily available source of Ca in the fruiting zone during fruit development. Field studies were conducted for three years on two soils to compare rates of fine and coarse gypsum material applied to peanuts shortly after planting and at early flowering in supplying Ca to the peanut fruit and its effect on yields. The fine and coarse gypsum was applied at three rates and at two different times in randomized complete block experiments. At approximately every four weeks, composite soil samples were collected at 0–5 and 5–10 cm depths and extracted with (0.05N HC1 + 0.025N H2 SO4) extractant. On the Lakeland soil fine gypsum applied at early flowering gave higher Ca levels at the 0–10 cm depth than coarse material applied shortly after planting or at early flowering. Yield data showed that at low rates coarse gypsum applied at planting was superior to early flowering application. In most instances on the Greenville soil, coarse gypsum applied at planting produced higher levels o...

Soybean root morphology in soils with and without tillage pans in the lower Mississippi river valley 1

Abstract During 1980, an extremely dry growing season, soybean (Glycine max L. Merrill) root morphologies were characterized at the R2 growth stage in Steele, Sharkey, Rilla, Calloway, and Stuttgart soils with a tillage pan and with a disrupted tillage pan. Results showed that the presence or absence of tillage pans resulted in dramatic changes in the soybean root morphology. Without pans, classical taproot systems tended to develop. With pans, soybean root systems tended to follow old root channels and fractures through the pan. Below the pan, soil structure manifested strong influences on root morphology. On all soils except the Steele (loamy sand), roots penetrated the tillage pan in numbers comparable to those penetrating the soil horizons with the pan disrupted. Although soil impedance to root penetration increases with drying and the 1980 growing season was exceptionally dry, mechanical impedance to soybean root penetration of tillage pans on silt loam and clay soils did not appear to be a problem. ...

Nitrogen efficiency of grain sorghum grown on flat and raised seedbeds on poorly drained soil

Abstract Grain sorghum (Sorghum bicolor L. Moench) production commonly occurs on poorly drained clayey soils of the Mississippi River delta region inArkansas. Raised, wide seedbeds may improve grain yield and fertilizer N efficiency for narrow‐row sorghum production on these soils. The influence of individual row positions on raised, wide seedbeds was compared to conventional flat seedbed for grain yield, yield components, dry weight, and N uptake. A 193‐cm wide and 15 cm high crowned seedbed (CB) was compared to the flat seedbed (FB) in 1987 and 1988 on a Sharkey silty clay (very fine, mont‐morillonitic, nonacid, thermic, Vertic Haplaquepts) at Keiser, AR. Three rows were planted on each seedbed treatment; one in the middle of the bed and one row 48 cm to each side of the row in the middle. Nitrogen rates of 0, 56, 112, and 168 kg/ha were applied at planting. In addition, two split applications at the 168 kg/ha N rate (56 kg N/ha at planting and 112 kg N/ha at either four‐leaf or eight‐leaf growth stage)...

Soybean yield and water extraction in response to deep tillage and high soil aluminum

An adequate water supply is the major factor limiting soybean [Glycine max (L.) Merr.] yield throughout the world. Increasing the rooting volume for water extraction by eliminating chemical and physical barriers is an important strategy for drought avoidance. Aluminum-toxic soils reduce crop root growth and subsequent water uptake, and may affect grain yield. These experiments evaluated the effects of aluminum tolerance, tillage, and row spacing on soybean grain yield, root growth patterns, canopy temperature, and leaf gas exchange under water-limited conditions on a soil which had a tillage pan and which had high soil aluminum at depths >15 cm. During the three-year experiment, deep tillage did not affect grain yields. In 76-cm rows, a breeding line selected for aluminum-tolerance in hydroponics (R93-5455) had greater yields than an aluminum-sensitive cultivar (Hutcheson) under severe drought-stress conditions. In 19-cm rows, yield was similar for both cultivars and greater than yields in 76-cm rows. R93-5455 grown in 76-cm rows had significantly higher root counts in the upper-most 15 cm of soil compared with Hutcheson. It was concluded that the advantage of R93-5455 in 76-cm rows was due to greater rooting density and soil-water extraction in the upper soil horizons compared with Hutcheson. The low rooting density of Hutcheson in wide rows was compensated by narrowing row spacing and increasing population density. *This paper is published with the approval of the director of the Arkansas Agricultural Experimental Station (manuscript number 01074).

Wheat production on raised beds on clayey and silt loam soils

Abstract Winter wheat (Triticum aestivum L.) production commonly occurs on poorly‐drained soils of the Mississippi River Delta region in Arkansas. Wheat has historically been planted on a conventional flat seedbed (CFS); however, the use of raised beds may improve drainage, grain yield, and nitrogen (N) fertilizer efficiency. Wheat production on (76 inch) wide raised crowned beds (CB) and raised flat beds (FB), were compared to the CFS in seven experiments. The more conventional 38 inch wide CB was compared to the CFS in four additional experiments. The eleven experiments were conducted from 1986 to 1991 at Keiser on a Sharkey silty clay (very fine, montmorillonitic, nonacid, thermic, Vertic Haplaquepts) and at Colt and Marianna on a Calloway silt loam (fine‐silty, mixed, thermic, Glossaouic Fraqiudalfs). Wheat grain yield was measured. Wheat in the center of the raised beds had higher yields than wheat near or in the water furrows. Increases in the number of spikes and kernels per spike is the source of ...