bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Laboratory Methods for Determining Quality of Corn and Sorghum Silages: I. Biological Methods for Predicting In Vivo Digestibility1
Authors: Schmid A. R. , Goodrich R. D. , Marten G. C. , Meiske J. C. , Jordan R. M. , Halgerson J. L.
Published: July 2010

While many laboratory procedures have been proposed for estimating feeding quality of perennial grass and legume forages, none have been adequately tested for their potential in predicting quality of corn and sorghum silages. The objective of this phase of a comprehensive study was to assess the value of six biological procedures proposed for predicting forage digestibility of silages of corn (Zea mays L.) and sorghum (Sorghum bicolor (L.) Moench, S. sudanense (Piper) Stapf, and their hybrid).

In vivo digestible dry matter (DDM) of 51 corn and sorghum silages (17 in each of 3 years) was determined using sheep in conventional feeding trials.

A modified Tilley and Terry (1963) in vitro procedure (T‐T DDM), gave the highest correlations with in vivo DDM (r = 0.83 for corn silages and 0.91 for sorghum silages). A “direct acidification” in vitro rumen fermentation procedure resulted in in vitro DDM which was also highly correlated with in vivo DDM (r = 0.50 and 0.91 for corn and sorghum silages, respectively). Within the corn silages, the correlation between direct avidification DDM and in vivo DDM of 18 entries with high grain percentages was only 0.19, while that for seven entries with low grain percentages was 0.93. Apparently, the combination of large amounts of available carbohydrates in the high grain entries and the phosphate buffer led to erratic growth and digestive action by the rumen bacteria.

A 6‐hour rumen fluid fermentation procedure gave DDM values which were 36 to 38% of the T‐T DDM values and were poorly correlated with in vivo DDM. A cellulase‐acid pepsin procedure gave DDM values for both corn and sorghum silages that were 56% of the T‐T DDM values; however, cellulase‐acid pepsin DDM was positively correlated with in vivo DDM of sorghum silages (r = 0.72) and negatively correlated with in vivo DDM of corn silages (r = −0.42).

Two procedures that involved the neutral detergent extraction (Goering and Van Soest, 1970) and a 48‐hour rumen fluid fermentation gave in vitro DDM values which were highly correlated with in vivo DDM (r = 0.73 to 0.90).

A multiple correlation analysis revealed that little improvement of the simple correlation between specific laboratory procedures and in vivo DDM was attained by combining procedures.

We developed simple regression equations to predict in vivo DDM from T‐T DDM and direct acidification DDM for corn and sorghum silages.
Factors Affecting Cold Injury of Sugarbeat Seedlings1
Authors: Cary J. W.
Published: July 2010

Sugarbeet seedlings (Beta vulgaris L.) may be killed by Spring frost just as they emerge from the soil. Possible solutions to this problem were investigated under closely controlled laboratory and growth chamber conditions. The seedlings were germinated at different temperatures in contact with solutions containing both varying osmotic pressures and compounds known to promote cold‐hardiness in other plants. Following germination, the seedlings were frozen in blocks of ice at different minimum temperatures and the degree of injury was noted.

The results indicated that two mechanisms were involved in seedling survival. One was related to the osmotic potential of the plant sap and the other to the amount of water in the sap that could be converted to ice without killing the seedlings. Seedling osmotic pressures could be increased through the solution in contact with the roots, while the tolerance for ice could be increased with cool temperatures during germination. These two factors had a strong positive interaction and could reduce the normal lethal temperature from −0.5 to −2.5 C. Growth regulators and other compounds that have been reported to increase cold‐hardiness in other plants were not effective.
Seed Appendages and Germination of Two Asiatic Bluestems1
Authors: Ahring R. M. , Eastin J. D. , Garrison C. S.
Published: July 2010

Establishment of several grass species is difficult because of seed dormancy. The objective of this research was to evaluate the inhibitory effects on germination of substances from the bracts (glumes, lemma, palea), which enclose the caryopses of two Asiatic bluestems, Bothriochloa ischaemum (L.) Keng var. ischaemum (‘M’ strain) and B. intermedia (R. Br.) A. Camus (‘T’ strain).

Standard germination tests demonstrated that the germination capacity of caryopses of both strains freed of appendages by hand was significantly greater than that of the rough seed units. Ether‐soluble inhibitors were present in aqueous refluxed material from empty bracts of both strains. The heavy oily residue of this extract after ether evaporation significantly retarded seedling growth in both strains. Ether extracts from empty bracts subjected to a 72‐hour 65 to 70 C heat treatment did not inhibit germination of lettuce seed. Ether‐soluble inhibitors in the untreated bracts were heat liable and concentration‐dependent for inhibition effects.

The inhibition of germination in fresh seed of both species was caused, at least in part, by substances within the bracts. Heat drying appeared to cause a degradation of these biologically active compounds(s). Thin‐layer chromatography showed that certain compound(s) were immediately or progressively lost with each increment of treatment duration. Appropriate drying of the rough seed units prior to planting would reduce the inhibitory effects of natural ether‐soluble components within the bracts and increase the probability of stand success.
Potassium Uptake by Cotton in Relation to Verticillium Wilt1
Authors: Hafez A. A. R. , Stout P. R. , DeVay J. E.
Published: July 2010

Increasing evidence of a close relationship between K‐nutrition of cotton plants (Gossypium hirsutum L.) and verticillium wilt (Verticillium dahliae Kelb) development was observed in certain K‐deficient soils in San Joaquin Valley, California. Therefore, a K uptake field experiment on verticillium‐infected K‐deficient soil with 270 kg K/ha fertilized and unfertilized plots were conducted on both (420 liter/ha) chloropicrin (trichloronitromethane) fumigated and non‐fumigated treatments. The uptake of fertilizer K was traced by the “reverse‐tagging” procedure in which the indigenous soil‐Rb was used as a tag for K. In this instance the fertilizer Rb/K ratio was about 0.01 of the Rb/K ratio of the labile K in the upper foot of the soil profile.

Cotton plants grown on fumigated soil absorbed 62% of their leaf K from the fertilizer source versus 48% for the non‐fumigated soils. Also it was observed that in the unfertilized plots, fumigation induced shifts in Rb/K ratio in plant tissues, which is explained by the differences in the Rb/K ratios in the upper and lower soil horizons coupled with reduced uptake efficiencies when roots in the upper soil horizons are infected with verticillium wilt.

K‐fertilization alone resulted in a significant decrease in verticillium wilt. In both fumigated and non‐fumigated plots, yields of cotton lint responded significantly to K‐fertilization. However, corrections of K deficiency symptoms of cotton leaves required a combination of soil fumigation with chloropicrin and K‐fertilization.
Time of N Application and Yields of Corn in Wet, Alluvial Soils1
Authors: Miller H. F. , Kavanaugh John , Thomas G. W.
Published: July 2010

Time and rates of N application to corn (Zea mays L.) grown in wet alluvial soils in western Kentucky were studied in the years 1968 through 1972. Two soils representative of the wetter soils in the area were used, Stendal silt loam and Melvin silt loam. The objective of the study was to determine the N fertilization practices that would produce highest corn yields on such soils. The early experiments were concerned with Fall vs. Spring application of N as practiced in the Midwest, but Fall‐applied N at lower rates (90 or 112 kg/ha) gave no better yields than the check treatments and even at relatively high N rates (180 and 224 kg/ha) gave such a poor response that this was changed to a comparison between Spring and Summer side‐dress applications for the last 2 years. Side‐dress application of N was nearly as good as or better than N applied at planting at both locations, although increasing the N rate at planting tended to obscure this effect. The results show that Summer side‐dressing of N on corn grown in wet soils is an effective way of fertilizing corn. They also suggest that late N application on corn made severely N deficient by excessive rain is an excellent practice.
Ratoon Cropping of Sorghum: II. Effect of Daylength and Temperature on Tillering and Plant Development1
Authors: Escalada Rodolfo G. , Plucknett Donald L.
Published: July 2010

Tillerlng capacity and behavior determine the success or failure of ratoon cropping in grasses. This work was initiated to gain more understanding on the seasonal effects on tillering and ratoon cropping of sorghum [Sorghum bicolor (L.) Moench] in the high rainfall tropics by studying the effects of various daylengths and temperature regimes on plant growth and development and yields of ratoon crops.

Sorghum plants were grown under two daylengths and four temperature regimes in controlled‐environment chambers. Temperatures and daylengths used simulated tropical winter and summer conditions similar to rainfed sugarcane (Saccharum officinarum L.) plantations of Hawaii where ratoon sorghum has been grown. It is contemplated that sorghum could be used as an alternate crop for sugarcane plantations phasing out of production and that ratooning the crop could be utilized as a management practice, thus reducing the high cost of production.

An interaction between photoperiod and temperature was observed. With low temperature (23.9 C‐day/15.5 C‐night) and short day (10 hours), fewer tillers/plant were produced resulting in the development of fewer reproductive tillers. At the same low night and day temperatures, but with photoperiod increased from 10 to 14 hours, more tillers/plant, more reproductive tillers/plant, greater leaf area, more leaves, more numerous but shorter internodes, and longer panicles were produced. The check plants grown outside produced more reproductive tillers/plant than the various treatments. Increasing both the temperature (32.2 C‐day/23.9 C‐night) and daylength (14 hours) resulted in further increase in tiller number/plant, leaf area, and internode number. Higher temperature and shorter daylength tended to bring about early maturity.

Low light intensity, short photoperiod, and low temperature, resulted in rosette form of foliage with very short internodes and reduced number of leaves. This condition led to low grain and stover yields.
Influence of Environment on Protein Content of Rice1
Authors: Gomez K. A. , De Datta S. K.
Published: July 2010

Recognition of world‐wide protein malnutrition has focused greater emphasis on improving rice (Oryza sativa L.) protein content, either through breeding for high‐protein cultivars or through manipulation of environment and cultural practices. This study was undertaken to investigate the overall influence of environment on the protein content of rice, to identify cultural practices that can be used to increase protein content without sacrificing grain yield, and to examine the relationships between grain yield and protein content.

Since 1968, the International Rice Research Institute has collected from rice field experiments voluminous data on grain yield and protein content on several of its promising rice cultivars. For this study, we examined data from 964 experimental plots of ‘IR8’ and 538 plots of ‘IR480‐5‐9.’ Protein content ranged from 4.8 to 12.1% in IR8 and 6.4 to 17.4% in IR480‐5‐9. Crop season, location, N fertilization, water management, and weed control were the major sources of variation in protein content. It was also found that grain yield and protein content can be increased simultaneously, but only up to a certain point (protein‐yield threshold) beyond which further increase in the protein content results in a decrease in grain yield. The protein‐yield threshold was higher for IR480‐5‐9 (10.3%) than for IR8 (8.5%). The existence of protein yield threshold in rice cultivars has significant implication in the improvement of protein content in rice grains, either through breeding or improved cultural practices.
N Behavior Under No‐Till vs. Conventional Corn Culture. I. First‐Year Results Using Unlabeled N Fertilizer1
Authors: Bandel V. A. , Dzienia Stanislaw , Stanford George , Legg J. O.
Published: July 2010

This study comparing corn yields from different rates of applied N under no‐tillage and conventional culture was prompted by numerous field observations in Maryland that no‐till corn, with low to moderate rates of N, often showed more pronounced N deficiency symptoms than did conventionally tilled corn. Little is known regarding the relative N requirements of untilled corn grown in cover‐crop residues as compared to conventional tillage. The purpose of this study was therefore, to determine whether tillage method affected optimal crop requirements for fertilizer N. First‐year effects of tillage method and fertilizer N applications (0, 45, 90, 135, and 180 kg/ha) on corn (Zea mays L.) yields, N uptake by the crop, mineral N accumulation in the soil, and total and potentially mineralizable soil N are reported. With suboptimal N rates, N deficiency symptoms were more severe throughout the season on untilled than on cultivated plots. However, the optimal level of applied N for grain and dry matter yields did not differ with tillage method. After grain harvest, the amount and distribution of residual mineral N in the root zone for a given rate of applied N were similar in tilled and untilled plots at two locations (Poplar Hill and Plant Research Farm). At the third site (Wye Institute), however, residual mineral soil N was higher with conventional than with no tillage. These differences were attributed to variation among sites in amounts of precipitation between planting and harvest, as it affected relative water infiltration in tilled and untilled plots. Total residual mineral N in the root zone tended to increase with N application rate. Between harvest (1973) and planting (1974), however, most of the residual mineral fertilizer N was removed by the cover crop or lost.

Total soil organic N to a depth of 30 cm was unaffected by N rate or tillage method during one cropping season. At one rate, however, potentially mineralizable N was higher in untilled than in tilled plots. Studies are continuing on two of the sites, with l5N‐lepleted fertilizer, to determine relative changes with time in soil N status as influenced by tillage method.
Compatibility of Rhizobium japonicum with Chemical Seed Protectants1
Authors: Curley R. L. , Burton J. C.
Published: July 2010

The literature on the compatibility of Rhizobium sp. with seed protectant chemicals is controversial because of variation in methods and the lack of quantitative data. The present study was planned to develop a reliable quantitative method of measuring compatibility of Rhizobium japonicum with seed‐applied fungicides. The effect of four seed protectant chemicals on survival of R. japonicum on soybean (Glycine max L. Merr. cv. ‘Hark’) seed was studied in laboratory growth chamber experiments. The chemicals tested and levels used were tetramethyl‐thiuram‐disulfide (thiram), 0.6 g/kg seed; N‐trichloromethylthio‐4‐cyclohexene‐l,2‐dicarboximide (captan), 0.8 g/kg seed; 5,6‐Dihydro‐2‐methyl‐l,4‐oxathiin‐3‐carboxanilide (carboxin), 1.1 g/kg seed; and pentachloronitrobenzene (PCNB), 0.9 g/kg seed. Quantitative measurements for compatibility included plate counts for survival of R. japonicum on inoculated chemically treated seed and counts of taproot nodules on plants at 2 weeks age. R. japonicum were compatible with Thiram and Carboxin but not with PCNB and Captan. PCNB reduced Rhizobium survival on seed and decreased taproot nodulation. Captan was less toxic to rhizobia than was PCNB, but taproot nodulation of plants was greatly reduced by captan. Carboxin had little effect on viable rhizobia or taproot nodulation when seeds were planted within 4 hours of inoculation. Nodulation was poor when these seeds were planted 24 hours after inoculation despite the presence of what would normally be considered adequate viable rhizobia. Thiram had no adverse effect on viable rhizobia or taproot nodulation even when seeds were held 24 hours before planting. The results also indicate that compatibility must be measured quantitatively in relation to time and that nodulating ability of the surviving bacteria is the prime factor in determining compatibility.
Hydrocyanic Acid Potentials in Leaf Blade Tissue of Eleven Grain Sorghum Hybrids
Authors: Eck Harold V.
Published: July 2010

Hydrocyanic acid potentials (HCN‐p) of grain sorghums [Sorghum bicolor (L.) Moench] need not be considered in grain production but become important when fresh forage is fed to livestock. This study involved determination of seasonal leaf blade HCN‐p levels of 11 field‐grown grain sorghum hybrids, relationships between HCN‐p levels in growth chamber‐grown seedlings and older fieldgrown plants, and effects of N fertilization on seasonal leaf blade HCN‐p levels.

Growth chamber plants were grown in vermiculite, subirrigated daily with nutrient solution. Plants were harvested and assayed for HCN‐p 10, 14, and 18 days after planting. In 1972, the 11 hybrids were field‐grown on N fertilized soil. In 1973, ‘DeKalb E‐59’ was grown on N fertilized and on N‐deficient soil. Field‐grown hybrids were assayed for HCN‐p weekly from 27 (1972) or 37 (1973) days after planting until physiological maturity. HCN‐p was determined potentiometrically on homogenized, β‐glucosidase hydrolized leaf blade tissue.

Relationships between HCN‐p levels at sampling dates during the season and seasonal average HCN‐p levels indicated that, for purposes of ranking cultivars, approximately equal precision would be attained at any time from growing point differentiation through soft dough. The correlation between HCN‐p levels in 18‐day‐old growth‐chamber plants and seasonal average HCN‐p levels of field plants was significant at the 10% level (r = 0.56) but HCN‐p levels in 10‐ and 14‐day‐old plants were not significantly related to seasonal average HCN‐p levels of field plants. HCN‐p in leaf blade tissue was highly dependent on N availability. At a sustained adequate level of N, HCN‐p levels in sorghum leaf blade tissue declined from the seedling stage to about flag leaf and then remained fairly constant until they declined at the approach of maturity. HCN‐p levels exceeded the “threshold of danger” (200 ppm) until physiological maturity. On N‐deficient soil, leaf blade HCN‐p levels declined to a low level (<100 pm) at soft dough.
Nitrogen Accumulation and Translocation in Corn Genotypes Following Silking1
Authors: Beauchamp E. G. , Kannenberg L. W. , Hunter R. B.
Published: July 2010

The potential for improvement of N utilization in corn (Zea mays L.) can depend on the existence of genotypic differences. Accordingly studies were conducted to determine if N translocation from the leaves and stalk to the ear during the period immediately following silking depended on the genotype. In 1970, the N concentration of individual leaf blades, stalk, and developing ears of four inbreds was determined at the silking stage and 14 and 28 days after silking. In a similar experiment in 1971, using bulked leaf blade samples, three of the inbreds plus their F1 hybrids were analyzed for N at silking and 24 days after silking.

In 1970, the apparent translocation of N from individual leaf blades differed considerably depending on the inbred Significant differences in N concentration in either the stalks or developing ears occurred among genotypes in 1970 and 1971. Appreciable differences were found in the apparent propensity of the inbreds to translocate N to the developing ear. In 1970, apparent N translocation during the 14 to 28 day period was greater than during the first 14 days following silking. The inbreds differed between years with respect to apparent N translocation suggesting a genotype ✕ environment interaction.

The N accumulation rate following silking was substantially greater in one of the three F1 hybrids than in the parent inbreds. Thus there appears to be some potential for the screening and development of hybrids capable of accumulating a relatively large quantity of N or using N more efficiently through translocation from various plant parts.
Drying Rates of Frosted Maturing Maize1
Authors: Hicks D. R. , Geadelmann G. L. , Peterson R. H.
Published: July 2010

Freezing air temperatures sometimes occur in early autumn before maize (Zea mays L.) grain is physiologically mature. A study was conducted to determine maize grain, cob, and ear moisture profiles following certain treatments to simulate plant conditions which exist after a subfreezing temperature occurrence.

Ears with husks and shanks attached were removed from plants and placed in a controlled temperature chamber for 0, 4, or 8 hours at −7 C. Three husk treatmeats‐loosened, normal, or tied‐were imposed on ears subjected to the three cold treatments. Treated ears were taped onto plants in the normal ear position for field drying. Ears from these nine treatments and also ears from completely defoliated and control plants were sampled weekly from 19 Sept. to 23 Oct. 1974, to estimate drying rates of grain, cobs, and ears.

Grain drying rates ranged from 0.83 to 1.16% moisture loss⁄day. Drying rates of grain following leaf blade defoliation or moderate to severe cold treatments were not statistically different from the drying rate of normally maturing maize grain. Husk condition did not statistically affect grain drying rates.

Defoliation and cold treatments caused grain moisture levels to be 2 to 6 percentage points greater than that of grain from control plants when grain from control plants was in the 22 to 30% harvest range. Grain from these treatments required 4 to 9 additional days of field drying to reach the 22 to 30% moisture range.

Defoliation and cold treatments had little effect on the drying rates of cobs and ears. However both cob and ear moisture levels were greater than those of the control throughout the sampling period. Loose husks caused faster cob and ear drying compared to normal or tied husks which had similar cob and ear drying rates.
Border Effects in a Long‐Term Fertility Experiment1
Authors: MacDonald G. E. , Peck N. H.
Published: July 2010

The concept of plot border effects in a fertility experiment is well known. However, the magnitude of the possible border effects is often unappreciated. Thus an experiment was designed to determine how much horizontal movement of soil across plot boundaries results from normal tillage operations. Horizontal movement of P and K was determined by soil tests at the completion of a 10‐year fertility experiment during which 9 applications of differential rates of broadcast concentrated superphosphate (CSP) and potassium chloride (KCl) had been applied. Soil tests revealed that soil P was depleted to a distance of 2.7 m in the high CSP residual plots and moved into the low residual CSP plots 1.8 m. Soil K was depleted to a distance of 2.7 m in the high KCl residual plots and moved into the low KCl residual plots 2.7 m. Normal tillage operations moved soil in both directions across plot boundaries. The high CSP or KCl plots were depleted of fertility to about the same distance that the low CSP or KCl plots increased in fertility. The effective length of plots was reduced from 15 to 10 m for CSP plots and 9 m for KCl plots in the direction of the tillage operations after a period of 10 years. Dimension of long‐term fertilizer plots should be adjusted according to the number of years the experiment will be continued.
An Evaluation of a Resistance Form of the Energy Balance to Estimate Evapotranspiration1
Authors: Heilman J. L. , Kanemasu E. T.
Published: July 2010

Evapotranspiration (ET) models that use the air‐diffusion resistance to momentum (rD) have been unsatisfactory under certain conditions. A field study was conducted in soybean [Glycine max (L.) ‘Williams’] and sorghum [Sorghum bicolor (L.) ‘Pioneer 846’] to evaluate an ET model that uses the diffusion resistance to heat transport (rH) in the energy‐balance equation and to assess the effect of replacing the resistance for heat with that for momentum.

Resistances were determined using wind speed and temperature profiles. Model estimates of latent‐heat flux (LE) were compared with lysimetric measurements of LE. When using rH, model estimates of LE were within 4% and 15% of lysimetric measurements for soybean and sorghum, respectively. When using rD, estimates of LE for soybean were 25% greater, but for sorghum only 10% greater than when using rH. Results indicated that the resistance form of the energy balance can be useful for estimating ET if the proper resistance is used. Significant errors may occur if the momentum resistance is used in the model instead of the resistance for heat.
Influence of Tall Wheatgrass Wind Barriers on Soil Drying1
Authors: Aase J. K. , Siddoway F. H.
Published: July 2010

Virtually no direct measurements have been made to determine if wind barriers, in fact, do affect evaporation from bare soils. Our objective, therefore, was to quantify the effect of a tall wheatgrass (Agropyron elongatum) wind barrier system on soil drying from fallow soil compared with open‐field fallow. The experiment was done on a Williams loam soil (fine‐loamy, mixed, frigid family of Typic Argiborolls) near Sidney, Mont. We applied a 3.8‐cm irrigation and sampled for soil water content at half‐hour intervals and small depth increments to 10 cm. Ancillary data collected included wind in the barrier interval and in the open, plus global radiation, air temperature, and humidity in the open. The north‐south oriented system consisted of 8 double‐row tall wheatgrass barriers 1.2 m tall, 183 m long, with seven 15 m wide cropping intervals. For the study, we selected three locations in the third interval from the east, along with a location on an unprotected (check) area outside the influence of the barriers. The surface 4 cm of soil inside the barrier system remained wetter for about 3 days after the irrigation as compared with the check area. The drying rate remained constant at all four locations until approximately noon the day after irrigation. Thereafter, drying rate was influenced by exposure to wind. There are many periods of small, intermittent precipitation events during April and May when tall wheatgrass barriers could benefit a crop by creating a suitable soil water environment for seed germination, plant emergence and establishment, and soil resistance to wind erosion.
Seedcoat Structure in Coronilla varia and its Relations to Hard Seed1
Authors: McKee G. W. , Peiffer R. A. , Mohsenin N. N.
Published: July 2010

Hard seeds are common in some seedlots of crownvetch (Coronilla varia L.); such seeds are impermeable to water and require scarification before planting. However, unless carefully performed, scarification can lead to seedcoat injury with consequent loss of vigor and germinability. To locate the region or regions responsible for impermetability in ‘Penngift’ crownvetch, sized and known hard seeds were pierced to known depths and subsequently tested for imbibition of water and germination. All seeds punctured to a depth of 98 μm or more germinated rapidly while only 5% of those punctured to a depth of 47 μam or less subsequently germinated. Measurements of cross sections of crownvetch seeds indicated that the macrosclerid cells extended to a mean depth of 45 to 50 μm. In addition, an inner integument at an average depth of 73 μm also had to be pierced before germination occurred. Colors developed after staining with safranin and fast green indicated that the cuticle, macrosclerids and inner integument were lignified. Extensive deposits of tannin‐like materials were noted just below the inner integument.
Effects of Topping Pima Cotton on Lint Yield and Boll Retention1
Authors: Kittock D. L. , Fry K. E.
Published: July 2010

Substantial mid‐ and late‐season topping of American Pima cotton (Gossypium barbadense L.) plants occurs in field plantings. Lygus bug (Lygus hesperus Knight) feeding is the apparent cause of topping. The effects of mid to late‐season topping on lint yield and several yield components of ‘Pima S‐4’ cotton were examined. Topping of Pima S‐4 cotton in mid‐July, early‐August, and mid‐August reduced plant height, reduced the number of main stem nodes, increased boll set on top fruiting branches, and resulted in additional branch nodes on top fruiting branches. Plants topped 17 July produced 300%, 100%, and 60% more bolls on the first, second, and third branch, respectively, below the point of topping than did the check plants. The effect was less when topping was later in the season. The yield patterns in lower branches were not different from the checks. Topping did not affect: 1) lint yield (3 years), 2) number of bolls set, 3) seed/boll, 4) lint/boll, 5) lint/seed, 6) seed weight, 7) days to boll maturity, or 8) pink bollworm infestation. Fruit set was not delayed by topping. Fruiting points, which aborted on normal plants, produced bolls on topped plants up to the potential for the cultivar and environment. This has important implications for studies on insect damage to plants and for efforts to increase lint yield by reducing boll abscission.
Comprehensive Nitrogen Fertilizer Management Model for Winter Wheat1
Authors: Jackson Grant D. , Sims James R.
Published: July 2010

Systems for predicting fertilizer N rates on dryland winter wheat (Triticum aestivum L.) in Montana have needed refinement for several years. The objective of this study was to develop a comprehensive N fertilizer management model for dryland winter wheat based on soil properties and climatic factors. Data for multiple regression analysis were gathered from 47 locations rep resenting 4 growing seasons. A stepwise multiple linear regression technique was used to generate equations for predicting optimum grain yield, grain protein content at optimum yield levels, N fertilizer rate needed to achieve optimum yield, post‐harvest soil NO3‐N in surface 30 cm of soil, and grain yield and protein content without N fertilization. Statistically significant equations were developed for all functions except post‐harvest NO3‐N when excessive N fertilizer rates were used. Growing season rainfall, pan evaporation rate, soil temperature, initial soil NO3‐N, soil organic matter content, available soil water, grain yield, and grain protein content were the important variables.
Influence of No‐tillage and Nitrogen Fertilization on Certain Soil Properties after 5 Years of Continuous Corn1
Authors: Blevins R. L. , Thomas G. W. , Cornelius P. L.
Published: July 2010

In no‐tillage management systems for row crop production, plant residues, lime, and fertilizer are not incorporated into the soil. A major concern in continuous no‐tillage farming is what effect not incorporating these materials will have on soil properties and nutrient availability. The purpose of this study was to compare the effects of 5 years of continuous no‐tillage and conventional‐tillage of corn (Zea mays, L.) on certain chemical and physical properties of the soil. A field experiment was initiated in 1970 on a Maury silt loam (Typic Paleudalfs) soil. The experimental site had been in bluegrass (Poa pratensis, L.) for the past 50 years. A split‐block design with four replications of treatments of 0, 84, 168, and 336 kg N/ha was used in combination with no‐tillage and conventional‐tillage. After 5 years of continuous corn production, soil samples from all treatments were analyzed for selected chemical and physical properties. Neither tillage treatment or N treatment had a statistically significant effect on soil density. Exchangeable Ca decreased with increasing rates of N but tillage methods did not significantly effect exchangeable Ca. Exchangeable Al increased with N rates and was higher under no‐tillage than under conventional‐tillage. The soil pH was lowered by increasing N rates and was lower with no‐tillage than with conventional‐tillage. Organic C was significantly higher under no‐tillage and increased with increasing N rates. Organic soil N followed the same trends as organic C. Exchangeable Mg decreased under both tillage methods. No tillage with moderate rates of N most nearly preserved the soil chemical characteristics found under the original bluegrass sod.
Factors Determining Germination of Indian Ricegrass Seeds1
Authors: McDonald M. B. , Khan A. A.
Published: July 2010

Indian ricegrass, Oryzopsis hymenoides (Roem. & Shult.) Ricker is an important forage crop in the western United States. The seeds of this species are dormant at harvest and even following several years of storage. In spite of several attempts by various workers to uncover the factors responsible for dormancy, little progress has been made to date. The present investigation was undertaken to reexamine in detail the nature of dormancy in these seeds with emphasis on the effects and possible roles of hormones in release of dormancy. The seed coats of Indian ricegrass seeds prevented germination and were shown to delay the uptake of water, gibberellic acid, and tetrazolium salts by the seed. The acid scarification proved the only effective method of breaking dormancy imposed by the seed coats. One‐year‐old scarified Indian ricegrass seeds were also shown to exhibit a post‐harvest dormancy which was overcome by 10 μM gibberellic acid and 10 μM kinetin. Intact seeds contained abscisic acid and the level of this inhibitor decreased following scarification. Gibberellic acid was incorporated into scarified Indian ricegrass seeds by acetone permeation suggesting a commercial preparation for these seeds.
Giant Foxtail and Velvetleaf Control in Sweet Corn1
Authors: Harvey Robert G. , Andrew Robert H. , Ruscoe Alfred W.
Published: July 2010

Velvetleaf (Abutilon theophrasti Medic.) and giant foxtail (Setaria faberi Herrm.) are among the most serious weed problems in sweet corn (Zea mays L.) grown in the north central U.S. While several herbicide treatments have been used to partially control these weeds, the treatments frequently leave soil residues which can injure susceptible crops commonly grown in rotation with sweet corn. Consequently, studies were conducted over a 3‐year period on fields (Plano silt loam, 3.5 to 4% organic matter, Typic Argindoll fine silty mixed mesic) heavily infested with velvetleaf and giant foxtail to compare the effectiveness of 10 herbicides applied alone and in 36 combinations in controlling these weeds. Visual observations of sweet corn injury and weed control were obtained and the sweet corn was harvested to determine the effects on yields. Oats (cv. ‘Lodi’) and peas (cv. ‘NK‐692’), which commonly follow sweet corn in a crop rotation and which are susceptible to residues of common herbicides, were grown over the plot areas the year following sweet corn and evaluated for carryover injury. Of the herbicide treatments included in the study, the best overall weed control and the largest average sweet corn yields were produced by a sequential application of 2.2 kg/ha alachlor [2‐chloro‐2',6'‐diethyl‐N‐(methoxymethyl) acetanilide] applied premergence and 1.1 kg/ha bentazon [3‐isopropyl‐1H‐2,1,3‐benzo‐thiadiazin‐(4)3H‐one 2,2‐dioxide] applied postemergence and by a preemergence combination of 2.2 kg/ha alachlor and 0.6 kg/ha metribuzin [4‐amino‐6‐tert‐butyl‐3‐(methylthio)‐as‐triazin‐5 (4H) one]. Preplant incorporated combinations of butylate (S‐ethyl diisobutylthiocarbamate) with atrazine [2‐chloro‐4‐(ethylamino)‐6‐(isopropylamino)‐s‐triazine] or cyanazine [2‐([4‐chloro‐6‐(ethylamino)‐s‐triazin‐2‐yl] amino)‐2‐methyl‐propionitrile] and preemergence combinations of alachlor with atrazine or cyanazine provided good weed control and satisfactory yields in 2 of the 3 test years. Three‐way combinations of atrazine, cyanazine, and butylate, as well as preemergence combinations of alachlor with bifenox (methyl 5‐(2,4‐dichlorophenoxy)‐2‐nitrobenzoate) or dicamba (3,6‐dichloro‐o‐anisic acid) and a preemergence and postemergence split treatment of cyanazine also showed promise. Preemergence treatments failed to control velvetleaf adquately in 1973 when insufficient rainfall was received, but preplant‐incorporated treatments failed similarly in 1974 following excessive rainfall. Postemergence treatments were typically best for controlling velvetleaf but did not satisfactorily control giant foxtail. The only injury to oats (Avena sativa L.) or peas (Pisum sativum L.) from soil residues persisting until the spring following sweet corn, occurred from atrazine applied at 3.4 kg/ha preplant‐incorporated in combination with butylate.
Detection of the Green and Brown Wave in Hardwood Canopy Covers Using Multidate, Multispectral Data from LANDSAT‐11
Authors: Blair B. O. , Baumgardner M. F.
Published: July 2010

Phenologic events which may be related to yields of economic plant species in humid and sub‐humid temperate regions are difficult and expensive to observe and measure. Sequential multispectral reflectance data obtained by an orbiting satellite (LANDSAT‐1) over 14 preselected sites in central and eastern United States during a 14‐month period were examined. Analysis of data from four reflectance bands (0.5 to 1.1 μm) indicated that foliage color, leaf senescence, and regrowth differences among hardwood timber stands can be detected and quantified. The results suggest the need for continued development of these monitoring techniques for use in detecting and quantifying conditions of economic plants which may affect yield.
Renovation of Tall Fescue Pasture with Lime‐Pelleted Legume Seed1
Authors: Olsen F. J. , Elkins D. M.
Published: July 2010

Lime pelleting of legume seed might protect Rhizobium and aid nodulation by providing a favorable microenvironment near developing seedling. The objective of this investigation was to determine if lime pelleting seed of selected forage legumes would aid renovation of tall fescue (Festuca arundinaceae Schreb.) pasture on an acid soil in Southern Illinois. This work was conducted on a Stoy silt loam soil classified as an Aquic Hapludalfs with a pH of 4.7. Seedbeds were prepared for oversowing legumes in tall fescue sod, by disking, and by chemical means plus disking. Seed treatments used were a) inoculation only and b) inoculation plus gum arabic and lime pelleting. They were applied to each of three forage legumes, alfalfa (Medicago sativa L.), ladino clover (Trifolium repens L.), and red clover (Trifolium pratense L.). With limited exceptions, lime pelleting of legume seed did not enhance early stand of legume seedlings, plant height, or legume ground cover. Dry matter herbage yields of legumes were not increased significantly by seed pelleting; however, tall fescue growth was stimulated by the introduction of legumes into the sward. The yield from most legume renovation treatments exceeded that of grass alone.
Rear‐Mounted Planter for Small Grain Yield Trials1
Authors: Cobb D. L. , Doyle B. L. , Webster J. A. , Smith D. H. , Ries D. K.
Published: July 2010

A four‐row single cone planter that could be easily detached from a tractor was needed for off‐station cereal leaf beetle (Oulema melanopus (L.)) research plots. The grain box and three disk openers were removed from a small seven‐row drill equipped with a three‐point hitch and a cone seeder with a four‐row divider was installed. A fertilizer attachment was also installed. The length of plots can be easily changed from 2 to 15 m with a variable speed drive which is part of the commercial cone unit. The planter has been successfully used in planting plots of wheat (Triticum aestivum L. em. Thell.), barley (Hordeum vulgare L.), and oats (Avena sativa L.)
Time and Rate of Fertilization on Seeded Warm‐Season and Bluegrass Pastures. II. Quality and Nutrient Content1
Authors: Rehm G. W. , Sorensen R. C. , Moline W. J.
Published: July 2010

There is relatively limited available information to be found which pertains to the effect of fertilizer application on the quality and nutrient concentration of seeded warm‐season as well as bluegrass pastures grown under more arid conditions. Therefore, this study was designed to measure the influence of the application of N and P fertilizers in early (mid‐April) and late (late May) spring on the quality (protein and in vitro dry matter disappearance) and nutrient (NO8−‐N, P, K, Ca, Mg) concentration of seeded warm‐season and bluegrass (Poa pratensis L.) pastures from 1971 through 1974. Applications of N (0, 45, 90, 135, and 180 kg/ha) and P (0, 8.5, 17, 25.5 and 34 kg/ha) were repeated in each of the 4 years. Whole‐plant samples were collected from each plot at harvest. These samples were analyzed for in vitro dry matter disappearance (IVDMD) and protein percentage. In addition, whole‐plant samples were collected from all plots approximately 30 days after fertilizer application in both 1973 and 1974. These samples were analyzed for NO3‐N, protein‐N, P, K, Ca, and Mg.

Fertilization with both N and P had no consistent effect on the IVDMD percentage of mature forage. The protein percentage of the mature forage increased linearly with rate of fertilizer N. Kentucky bluegrass forage had a higher percentage of protein than the mixture of warm season prairie grasses which consisted of big bluestem (Andropogon gerardi Vitman.), switchgrass (Panicum virgatum L.), indiangrass (Sorghastrum nutans (L.) Nash.), and sideoats grama (Bouteloua curtipendula (Michx.) Tarr.). Protein production from the bluegrass pasture was increased eight‐fold by application of both N and P. There was a six‐fold increase in protein production from the warm‐season prairie grasses when adequate rates of both N and P were applied. The concentration of P in samples collected at harvest as well as those collected 30 days after fertilizer application increased linearly with rate of applied P in all cases.

The ratio, , exceeded the critical value of 2.2 only when N and P were applied to the warm season grasses in early spring of 1974. The concentration of NO3−‐N in forage from both pastures was increased by applied N but did not approach the 2,000 ppm level generally considered to be lethal to livestock.
Effects of Preharvest Desiccation with Glyphosate on Grain Sorghum Seed1
Authors: Baur J. R. , Miller F. R. , Bovey R. W.
Published: July 2010

The preharvest application of chemical desiccants to reduce moisture content of grain sorghum (Sorghum bicolor (L.) Moench) may make it possible to eliminate costly mechanical drying of harvested grain. The objective of these experiments was to evaluate the effect of glyphosate on the viability of seed from field‐treated plants. Seed from grain sorghum plants desiccated with 1.12, 2.24 and 4.48 kg/ha glyphosate [(N‐phosphonomethyl) glycine] produced a high percentage of abnormal seedlings with varying amounts of interveinal areas completely devoid of chlorophyll. Mildly affected seedlings recovered from the symptoms and produced normal plants with normally appearing, viable seed. Severely varlegated plants died. Seed damage was greatest when treatments were applied 25 days after flowering when the grain had a moisture content of 30 to 40%. Damage decreased as time of treatment after flowering (30, 35, and 40 days) increased. The number of abnormal seedlings observed in standard germination tests corresponded to the number of variegated seedlings observed in growth evaluation studies. Similar effects were noted for genotypes ‘Top Hand’, BT− 399, and RT− 2536. The last two genotypes are similar to the female and male parents of Top Hand. Rate and time of treatment had no effect on yield of Top Hand.
Influence of Soil Organic Matter on Cowpea's Response to N Fertilizer
Authors: Agboola Akinola A.
Published: July 2010

There are divergent views on N application to legumes, especially cowpea. Results of various investigations in the tropics, especially Nigeria, have indicated either no response or a significant response to about 20 kg N/ ha. In Nigeria, a starter N is usually recommended irrespective of the cropping history of the field. As a result of these conflicting reports three field and one greenhouse experiments were carried out over a period of 4 years to investigate the effect of different levels of N, soil organic matter (O.M.), and split application of N on grain yield and performance of cowpea. Ife‐Brown, an improved variety of cowpea, was used as the test crop. The soils of the fields used were moderately to strongly leached luvisols, derived from metamorphic and igneous basement complex rocks under forest vegetation. The experimental design for each field experiment was a randomized, complete‐block design, while the greenhouse investigations was laid out in a split plot design. Cowpea was grown on fields having different cropping histories and levels of O.M. with various levels of N including no nitrogen as control. Cowpeas responded to N fertilizer; however, the level of O.M. affected the response. On soils having 0.5% O.M., grain yield was increased from 800 kg on the check to 1,850 kg dry grain per hectare, where 20 kg N/ha was applied, whereas on soils with 2% or more O.M. there was no constant response to N fertilizer.

In the greenhouse, N fertilizer did not effect the time of flowering and pod initiation of cowpea but the total number of flowers and pods were significantly affected. When 33.6 kg N/ha was applied at planting or split into two equal applications applied 2 and 4 weeks after planting, there was a significant increase in dry matter accumulation but low grain yield. In the latter treatment the cowpea fixed 33.07 mg N per pot compared with 40.10 mg N when 33.6 kg N/ha was applied at planting. The treatment that produced the highest grain yield fixed the lowest N. Application of N at planting and 2 weeks after planting depressed nodule number up till the 4th week, but 10 weeks the highest number of nodules was observed on cowpeas from the plots where N was applied at planting. It is concluded, therefore, that starter N should be used in soils having less than 2% O.M. Such starter N should be applied not later than 2 weeks after planting. Time of N application affects nodulation and N fixation.