bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soil Compaction and Moisture Stress Preconditioning in Kentucky Bluegrass. II. Stomatal Resistance, Leaf Water Potential, and Canopy Temperature1
Authors: Agnew M. L. , Carrow R. N. 
Published: July 2010

AbstractIn this greenhouse study we investigated the effects of soil compaction and moisture stress preconditioning on stomatal diffusive resistance (Rs), leaf water potential (Ψ1), and canopy minus air temperatures (ΔT) of Kentucky bluegrass (Poa pratensisL. ‘Ram I’). The compaction treatments were: (i) NC = no compaction, (ii) LT = long‐term compaction over a 99‐day period, and (iii) ST = short‐term compaction for 9 days. The compactive treatment was equivalent to 720 J energy. Irrigation regimes were initiated at the same time as LT compaction and were: (i) well‐watered = irrigation at −0.045 MPa and (ii) water‐stressed = irrigation at −0.400 MPa. Ninety‐nine days after initiation of preconditioning treatments, a dry‐down cycle was started by watering each treatment to saturation. At this time, we monitored on a daily basis Rs, Ψ1, and ΔT. Under low soil O2, Rsremained low for 2 days and then increased over a 5‐day period for all treatments, even though Ψ1did not change until the fifth day after irrigation (DAI). By DAI 9, Rsdeclined but then increased between DAI 10 to 13 as soil water potential (Ψs) and Ψ1decreased. As soil water deficits increased, plants preconditioned to LT compaction or water‐stressed exhibited lower Ψ1(0.2 to 0.4 MPa), higher Rs, and higher Δ (1 to 2°C) compared with uncompacted or well‐watered plants. Regardless of the cause for higher Rs(i.e., low soil O2, LT compaction or water‐stress preconditioning), the result would be lower photosynthesis and greater high‐temperature stress.
Intake and Digestibility of Dry Matter and Fiber of Flaccidgrass and Switchgrass1
Authors: Burns J. C. , Mochrie R. D. , Timothy D. H. 
Published: July 2010

AbstractSubtropical grasses are generally considered of lower nutritive value than temperate grasses. Flaccidgrass (Pennisetum flaccidumGriseb.) and switchgrass (Panicum virgatumL.) are subtropical species with high quality potentials. The objective of this study was to compare dry matter intake and the digestive coefficients for dry matter and several fiber constituents from hays of flaccidgrass (FG) and switchgrass (SG) with ‘Coastal’ bermudagrass [Cynodon dactylon(L.) Pers.] at similar neutral detergent fiber (NDF) concentrations. Initial growths were harvested as hay at appropriate development stages to obtain forages having similar NDF. Tall fescue (Festuca arundinaceaSchreb.) was included to provide comparisons with a temperate species. Hay intakes by eight Holstein heifers were measured in two squares of a 4 by 4 Latin square design. Digestion coefficients were calculated from data obtained during the fourth intake period of each square and were analyzed as a completely random design. The subtropical hays had similar NDF concentrations (0.710 to 0.753 g kg−1), but intakes differed. Coastal bermudagrass (CB) intakes of 2.70 kg 100 kg−1of body weight were followed by FG (2.29) and SG (2.09). Tall fescue (TF) intakes were similar to those for FG (2.25 vs. 2.29 kg 100 kg−1body weight). Dry matter digestibility of CB averaged only 0.496 compared with the greater but similar coefficients for the other three hays (0.624 g kg−1). The digestive coefficients for NDF and constituent acid detergent fiber (ADF) and cellulose were similar for FG, SG, and TF, averaging 0.649, 0.587, and 0.675, respectively, compared with lesser coefficients of 0.486, 0.435, and 0.517 from CB. Hemicellulose digestion was similar for FG and SG (avg 0.741) and appreciably greater than for CB (0.537); whereas, that for TF was intermediate (0.683). The greater digestibility of dry matter and fiber of FG and SG, compared with CB, partially explains the reported greater than expected animal daily performance from these two subtropical species and supports their use in ruminant feeding systems.
Tropical Legumes for Green Manure. I. Nitrogen Production and the Effects on Succeeding Crop Yields1
Authors: Reddy K. C. , Soffes A. R. , Prine G. M. 
Published: July 2010

AbstractThe energy shortage of the 1970s and knowledge that N prices may continue to escalate renewed interest in growing legume green manure crops to furnish N. The objective of this study was to evaluate the ability of selected green manure crops to furnish N to succeeding crops. This study evaluated seven tropical legumes and a marigold (Tagetes erectaL.) cv ‘Cracker Jack’ grown for different lengths of the summer under fumigation (F) and nonfumigation (NF) on Arredondo fine sand (loamy, silicious, hyperthermic Grossarenic Paleudults) during 1979, 1980, and 1981. Split‐plot and randomized complete block designs with five replicates were used. In the basic experiment, fumigation and nonfumigation were main plots and tropical legumes and fallow were the subplots. The green manure crops were grown for three different periods, early summer, full summer, and late summer. Early and late summer plantings usually included only the legume crops and fallow in a randomized complete block design. Average top growth N yields in kg ha−1were 40 for ‘PI 305070’ mungbean [Vigna radiata(L.) Wilcz.], 250 for ‘Norman’ pigeonpea [Cajanus cajan(L.) Millsp.], 190 for ‘FL 81d’ pigeonpea, 170 for showy crotalaria (Crotalaria spectabilisRoth.), 220 for hairy indigo (Indigofera hirsutaL.), 170 for jointvetch (Aeschynomene americanaL.), 190 for velvetbean [Mucuna deeringiana(Bort.) Merr.], and 60 for marigold. The dry matter yield of legumes (harvested before seeding) with higher N yields usually exceeded 10 000 kg ha−1for full‐season production in all 3 yr. Fumigation increased dry matter yield of legumes and marigold, but not their N yield.The grass crops, rye (Secale cerealeL.), ryegrass (Lolium multiflorumL.), maize (Zea maysL.), and wheat (Triticum aestivumL.) produced significantly higher dry matter (up to 100%) when planted after green‐manure summer legumes than when planted after summer fallow. Calculated uptake of N from green manure by these grass crops was relatively low, averaging from −2 to 23 kg ha−1. Applying 50 and 100 kg N ha−1as ammonium nitrate to the green‐manured plots did not increase recovery of N from green manure by wheat.
Effect of Mefluidide on Cool‐Season Perennial Grass Forage Yield and Quality1
Authors: Sheaffer C. C. , Marten G. C. 
Published: July 2010

AbstractSeasonal forage production of cool‐season perennial grasses is not uniform. Spring production is often under‐utilized in pastures while deficits frequently occur in the summer. We determined the effect of date of mefluidide {N‐[2,4‐dimethyl‐5‐[[(trifluoromethyl)sulfonyl] amino]phenyl]acetamide} application on distribution of forage yield and quality of orchardgrass (Dactylis glomerataL.), tall fescue (Festuca arundinaceaSchreb.), reed canarygrass (Phalaris arundinaceaL.), smooth bromegrass (Bromus inermisLeyss.), and Kentucky bluegrass (Poa pratensisL.) and the effect of a prespray clipping of these grasses on mefluidide activity. Two field experiments were each conducted for 2 yr on a fine‐silty over sandy or sandy‐skeletal, mixed, mesic Typic Hapludoll. In the first experiment, mefluidide (0.42 kg/ ha) was applied to the grasses in late September, late April, or mid‐May. In the second, mefluidide (0.42 kg/ha) was applied to the initial grass growth in early to mid‐May or to regrowth in late May to early June following an early spring defoliation. Forage dry matter yield and quality responded differently to mefluidide treatments each year in both experiments possibly due to differences in grass morphological development at application. However, all grass species responded similarily in yield or quality to meflufdide treatment. A late April mefluidide application (grasses vegetative, no culm elongation) consistently increased first harvest leafiness and forage quality compared to the control. Mean (over 2 yr) leaf/stem ratios and crude protein and neutral detergent fiber concentrations were 2.7, 16.3 dag/kg, and 54.6 dag/kg, respectively, for the April mefluidide treatment and 1.1, 13.1 dag/kg, and 61.5 dag/kg, respectively, for the control. However, increased forage quality was accompanied by decreased first harvest yields (mean yields of 2.0 and 4.0 Mg/ha for the April mefluidide treatment and control, respectively). Clipping spring growth before applying mefluidide to the regrowth had no consistent effect on grass forage yield or quality. Increased forage quality of the first crop due to mefluidide treatment may justify its use in extensive systems where surplus spring growth is usually wasted.
Yield and Seed Growth at Various Canopy Locations in a Determinate Soybean Cultivar1
Authors: Wallace S. U. 
Published: July 2010

AbstractThe purpose of this study was to investigate yield and seed growth in various parts of the canopy of a determinate soybean [Glycine max(L.) Merr.] cultivar. ‘Braxton’ soybeans were grown in a Cecil sandy loam soil (clayey, kaolinitic, thermic Typic Hapludults) with irrigation (I) applied when soil moisture tension exceeded 0.02 MPa and no irrigation (NI). Row width was 0.96 m, with intrarow spacings of 51, 102, and 152 mm in 1982 and 51 mm in 1983. Pods sampled during reproductive growth were separated into nine groups on the basis of pod location in one of three strata (based on canopy height) with a further separation into main stem pods or pods on lower, middle, or upper branches. Plot yields averaged 3068 and 1400 kg ha−1for the I and NI treatments, respectively. Intrarow spacing did not significantly influence yield. Yield in the upper canopy stratum increased from 33% of total crop yield in the NI treatment to 42% in the I treatment. With an increase in intrarow spacing from 51 to 152 mm, the relative yield contribution of main stems decreased from 31% of total yield to 15% while that of lower branches increased from 48 to 66%. Most pod groups did not differ in single seed weight, seeds per pod, or seed growth rate. These averaged 151 mg seed−1, 2.02, and 3.97 mg seed−1day−1, respectively. It was concluded that both irrigation and intrarow spacing influenced distribution of yield on branches and that yield increases in I soybeans were associated with increases in pod number and in percentage of total crop yield in the upper canopy.
The pe and pH Alfalfa Seedling Rhizospheres1
Authors: Blanchar R. W. , Lipton D. S. 
Published: July 2010

AbstractChanges in pe and pH of alfalfa [Medicago sativaL.] rhizospheres may be important considerations in the description of nodulation and nutrient uptake. Growth chamber studies were done where alfalfa seedlings were grown into a Sharon sandy loam soil and in situ measurements of pH and pe in zones 0 to 0.5, 0.5 to 1, and 1 to 3 mm from root surfaces made. The pe of the soil 0 to 0.5 mm from lateral and main roots was 7.8 ± 0.05 and was the same as that of the soil at greater distances. The pH in the zone 0 to 0.5 mm from lateral roots was 4.2 ± 0.3, in the same zone near main roots 6.8 ± 0.4, and at distances greater than 3 mm it was 5.54 ± 0.9.
Intraraceme Competition in Field‐Grown Soybean1
Authors: Spollen W. G. , Wiebold W. J. , Glenn D. Scott 
Published: July 2010

AbstractAbscission probability for positions within a soybean [Glycine max(L.) Merr.] raceme may not be equal. The influence of the two most proximal pods on abscission probability and growth of remaining pods within a raceme was studied using the soybean cultivar ‘Williams’. Plants were field grown (1982, Beltsville silt loam, Typic Fragiudult; 1983, Mattapeake silt loam, Typic Hapludult). Treatment consisted of removing or not removing the two most proximal (raceme Positions 1 and 2) pods. More flowers were produced at Node 8 than at either Node 10 or 12. Abscission probabilities for Positions 1, 2, 3, 4, and 5 of untreated racemes were 4, 10, 56, 77, and 99%. Removal of proximal pods decreased the abscission probability at Position 3 in five out of six instances (Nodes 8, 10, 1982; Nodes 8,10, and 12,1983) and at Position 4 in four of six instances (Node 8, 1982; Nodes 8, 10, and 12, 1983), but usually did not increase individual pod or seed weights. In most instances, individual pod and seed weights were smaller at Position 4 than at Position 1. The presence of proximal pods on soybean racemes interfered with the development of distal pods and increased the abscission probability of reproductive structures borne at distal positions.
Irrigation Effects on Agronomic Characters of Meadowfoam1
Authors: Pearson C. H. , Jolliff G. D. 
Published: July 2010

AbstractMeadowfoam (Limnanthes albaBenth.), a winter annual adapted to Mediterranean climates, produces a seed oil that has potential uses in industry. Insufficient water during flowering and seed development of meadowfoam might cause the highly variable seed yields previously experienced. The effects of irrigation on oil yield, seed yield and yield components, plant growth and development, and honey bee (Apis melliferaL.) foraging were determined. Irrigation treatments included: none (control), early irrigation (EI) during flowering, and continued irrigation (CI) from flowering until maturity. The soil was a fine‐silty, mixed, mesic Aquultic Argixeroll. Seed yield was not increased with irrigation in 1981, probably because above‐average precipitation occurred during May and June, but in 1982 seed yield in the irrigated treatments averaged 32% higher than in the control. Seed yield differences between the El and CI treatments were not significant. Seeds per flower and 1000‐seed weights in the irrigated treatments in 1982 were 9 and 5% higher than in the control, respectively. Bee foraging at late flowering was greater in the irrigated treatments than in the control. Greater bee activity in the irrigated treatments may account for more seeds per flower in these treatments than in the control. The seed oil content in the irrigated treatments was significantly lower than in the control; however, meadowfoam in the irrigated treatments in 1982 yielded 29% more total oil than in the control. Compared with the control, irrigated plants were taller in both years and in 1982 produced more dry matter and had a smaller canopy light transmittance. In some years meadowfoam can be successfully grown in Mediterranean climates without irrigation; however, in other years irrigation during flowering and seed development, particularly during flowering, may be required to achieve high seed and oil yields.
Development Rate and Growth Duration of Oats in Response to Delayed Sowing1
Authors: Colville D. C. , Frey K. J. 
Published: July 2010

AbstractNumber of days and number of growing degree‐days have both been used to predict plant development, but advantages of each are not completely understood. The effect of delayed sowing on the rate of development and duration of growth in oats (Avena sativaL.) was determined in field studies over 2 yr on a Coland loam (Cumulic Haplaquoll) soil at the Hinds Experiment Farm near Ames, IA. Number of growing degree‐days (GDD) and number of days to reach emergence, tiller initiation, fourth‐, fifth‐, and flag‐leaf stages, heading,and 80% panicle ripe were computed. Yield, bundle weight, and test weight were measured, and straw yield and vegetative growth index were calculated. Correlations were calculated for these values with number of days and with number of GDD to each stage of development.With delayed sowing, significant correlations occurred between yield factors and GDD, rate of development, and duration of growth. Number of days to reach each stage of development was significantly reduced by delayed sowing, whereas number of GDD was not. Neither, straw yield, or test weight. Both, however, could be useful for predicting rate of development and duration of growth; however, since number of GDD is less variable throughout a growing season, its use is recommended.
Alfalfa Response to Potassium, Irrigation, and Harvest Management1
Authors: Sheaffler C. C. , Russelle M. P. , Hesterman O. B. , Stucker R. E. 
Published: July 2010

AbstractThe purpose of this research was to evaluate the combined effect of irrigation, K fertilizer, and harvest management variables on the production of multi‐disease‐resistant, winterhardy alfalfa (Medicago sativaL.) cultivars. A field experiment was conducted on a sandy, mixed Udic Haploboroll to determine the effects of three irrigation regimes, three harvest managements, and four annual K rates (0, 167, 334, and 501 kg ha−1) on forage yield, forage quality, and persistence of‘Ramsey’ and ‘520’ alfalfa. No, full, and medium irrigation treatments were applied. Both full and medium irrigation regimes applied 3.5 cm of water when 50% of the extractable soil water had been depleted, but the medium irrigation was less frequent. Harvest managements consisted of: two harvests at full flower and one in late fall (HI), three harvests at one‐tenth flower and one in late fall (H2), and three harvests at one‐tenth flower (H3). Forage dry matter yield response to K increased with increasing irrigation, from 0.0033 Mg ha−1kg−1K in nonirrigated to 0.0058 Mg ha−1kg−1K in fully irrigated alfalfa. Yield response to K was similar for harvest managements within no and medium irrigation regimes, but for the full irrigation regime, yield increased 0.0071 Mg ha−1kg−1K with harvest at one‐tenth flower, and only 0.0031 Mg ha−1kg−1K with harvest at full flower. Following a severe winter after 2 yr of harvesting, the greatest stand and yield losses occurred with full irrigation and the most intensive (four‐cut) harvest management. Mean final stands in the four‐cut management were 19, 39, and 74% for full, medium, and nonirrigated alfalfas, respectively. Stand persistence and residual yield were increased by K fertilization under more frequent (one‐tenth flower) harvest of irrigated alfalfa. Cultivars did not consistently differ in yield in two production years, but the less winterhardy 520 had greater final stands than Ramsey. Potassium fertilization is beneficial to yield and stand of alfalfa, although the response varies with irrigation and harvest management.
A Procedure to Select Drought‐Tolerant Sorghum and Millet Genotypes using Canopy Temperature and Vapor Pressure Deficit1
Authors: Chaudhuri U. N. , Deaton M. L. , Kanemasu E. T. , Wall G. W. , Marcarian V. , Dobrenz A. K. 
Published: July 2010

AbstractPlant temperatures have been identified as indicators of plant water use and yield. The purpose of this experiment was to determine the potential of using canopy temperature for selecting drought‐tolerant genotypes. In 1983, 219 sorghum [Sorghum bicolor (L.) Moench] genotypes, assembled from Purdue University, the University of Arizona, Texas A & M University, and commercial seed companies, and 42 millet [Pennisetum americanum (L.) Leeke] genotypes from the University of Arizona, the University of Nebraska, and Kansas State University, were planted under a line source irrigation system at Yuma, AZ. The soil was a Typic Calciorthid. Five common sorghum hybrids also were used as checks. In 1984 only 27 genotypes of both crops were studied. Canopy temperature of the genotypes was measured for 7 days starting 67 to 60 days after planting in 1983 and 1984, respectively. Using all the data from each crop, an overall regression of canopy minus air temperature (DT) onto the observed vapor pressure deficit (VPD) was computed. This linear regression relationship was interpreted as the general relationship between VPD and DT for a crop. Also, a linear model of individual DT on the observed VPD was computed for each genotype. This equation predicted DT (DT) at a given value of VPD for each genotype. The sensitivity of each genotype to change in VPD was obtained by regressing the observed DT on the DT from the first regression. The genotype having coefficients < 1.0 are interpreted as having lesser sensitivity to changes in VPD. The mean temperature of a genotype higher than the average mean temperature of all the genotypes is considered as warmer. Warmer genotypes and those less sensitive to changes in VPD produce viable heads furthest from an irrigation sprinkler source.
Use of the Diagnosis and Recommendation Integrated System with Alfalfa1
Authors: Russelle M. P. , Sheaffer C. C. 
Published: July 2010

AbstractImproved means are needed to diagnose plant nutrient response to treatments. Our objective was to evaluate the sensitivity of two diagnostic techniques to irrigation, K fertilization, and harvest management of alfalfa (Medicago sativaL.). Comparison of forage concentrations of essential elements with critical values was not as useful in diagnosing the order of limiting nutrients as were Diagnosis and Recommendation Integrated System (DRIS) indexes. Several elements were present in the forage at concentrations below published critical levels, even at herbage dry matter yields of 13.9 Mg ha−1. The DRIS indexes reflected the general improvement in nutrient balance resulting from irrigation. Diagnoses based on DRIS indexes were not affected by harvest management, in contrast to the critical value approach. The relationship between the summation of absolute values of DRIS indexes and herbage yield was best described by a power function that incorporated a minimum index value at which yields were no longer limited by overall nutrient balance. The DRIS approach can effectively resolve nutritional responses of alfalfa to fertilizer and irrigation managements in the presence of differing harvest managements
Effect of Planting Date, Nitrogen Levels, Row Spacing, and Plant Population on Kenaf Performance in the San Joaquin Valley, California1
Authors: Bhangoo M. S. , Tehrani H. S. , Henderson J. 
Published: July 2010

AbstractKenaf (Hibiscus cannabinus L.) is an annual fiber crop whose stems are a potential source of paper pulp. It can be grown under different climatic conditions resulting in a wide range of yield. Several studies in the southeastern USA have shown positive yield responses from higher plant populations. Effects of N on yield have been inconsistent. This study was conducted on a Hanford sandy loam soil (coarse‐loamy, mixed, non‐acid, thermic Typic Xerorthent) at California State University, Fresno, and was designed to investigate the effects of planting date (20 May, 20 June, 20 July 1981), row spacings (38 and 76 cm), plant population (86 450,172 900, and 345 800 plants/ha, 1980) and N (0, 45, 90, 135, and 180 kg N/ha, 1980‐1983) on the components of biological yield, basal stem diameter, and root growth of the cultivars, Tainung‐1 and a variation of Cuba‐2032. Total dry matter and stem yields were maximized at 345 800 plants/ha. Tainung‐1 resulted in higher stem yield than that of Cuba‐2032. Narrow row spacing (38 cm) resulted in higher yields than 76‐cm row spacing for both cultivars. Basal stem diameter was 2.3 cm for the lowest plant population and decreased to 1.63 cm for highest population. Cultivars and row spacings had no effect on stem diameter. Total dry matter yield was highest for the 20 May planting and decreased significantly with delayed plantings. Applied N at the rate of 135 and 180 kg/ha resulted in 71.0 and 83.5% increases in yield over the 0 kg N/ha rate. Nitrogen content in whole plants and leaf tissue increased, whereas the P and K content in whole plants decreased with an increase in applied N. Root growth increased with N rates up to 90 kg N/ha but was depressed at the 180 kg N/ha rate.