International Journal of Agronomy The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Management of Vegetation by Alternative Practices in Fields and Roadsides Sun, 24 Aug 2014 07:25:11 +0000 In attempts to reduce the amounts of conventional herbicides used, alternative practices are sought in the management of roadside vegetation. In this investigation, alternative herbicides (citric-acetic acids, clove oil, corn gluten meal, limonene, and pelargonic acid), flaming, and mulching were assessed in management of annual and perennial, herbaceous vegetation in field and roadside plots. Several formulations of alternative herbicides applied singly or repeatedly during the growing season were evaluated and compared with conventional herbicides (glyphosate and glufosinate ammonium) or with flaming or mulching. Citric-acetic acid formulations, clove oil, limonene, or pelargonic acid applied as foliar sprays immediately desiccated foliage, but the efficacy lasted for no longer than five weeks. Repeated applications were better than single applications of these herbicides in suppressing plant vegetative growth. Corn gluten meal imparted little or no early control and stimulated late-season growth of vegetation. A single flaming of vegetation gave no better control than the alternative herbicides, but repeated flaming strongly restricted growth. Mulching with wood chips or bark gave season-long suppression of vegetation. Glyphosate gave season-long inhibition of vegetation, but the efficacy of glufosinate ammonium waned as the growing season progressed. For season-long suppression of vegetation with alternative herbicides or flaming repeated applications will be required. Allen V. Barker and Randall G. Prostak Copyright © 2014 Allen V. Barker and Randall G. Prostak. All rights reserved. Response of Soybean to Early-Season Planting Dates along the Upper Texas Gulf Coast Thu, 14 Aug 2014 09:22:51 +0000 Soybeans (Glycine max L.) can be planted along the upper Texas Gulf Coast from mid-March through May to take advantage of early season rains and to complete harvest before hurricane season and fall rains become a problem. However, in the Calhoun County area (28.5° north latitude), these planting dates have resulted in below average yields and reasons for these yield reductions are not clear. To determine if earlier planting dates could be an option to eliminate the low yields, field studies were conducted from 2005 through 2010 in Calhoun County, Texas, to determine soybean cultivar response to planting dates which ranged from mid-February through the last of April. Typically, soil temperatures in this area are above 18°C in mid-February and depending on weather patterns may not fall much lower during any time in the early portion of the growing season. The greatest yield was obtained with the mid-February and mid-March planting dates compared with early- or late-April planting dates. Typically, as planting date was delayed, the interval between planting and harvest decreased. W. James Grichar and Stephen P. Biles Copyright © 2014 W. James Grichar and Stephen P. Biles. All rights reserved. Effect of Cow Urine on the Growth Characteristics of Fusarium lateritium, an Important Coffee Fungus in Zimbabwe Wed, 23 Jul 2014 06:34:18 +0000 An in vitro assay was carried out to establish if cow urine at different concentrations (500 µL/mL, 300 µL/mL, 200 µL/mL, and 100 µL/mL) can be used to control the growth of F. lateritium, the fungal agent causing Fusarium bark disease in coffee. The growth characteristics selected were conidial germination, germ tube length, mycelial growth rate, and sporulation. Copper oxychloride 50% W.P. was the standard, distilled water was the negative control, and undiluted cow urine was the positive control. The undiluted cow urine was most effective in inhibiting fungal growth with the rest of the cow urine concentrations showing dose dependent efficacy compared to the negative control (P < 0.01). Copper oxychloride had the highest efficacy of all treatments with the exception of the inhibition of mycelial growth where undiluted cow urine had higher efficacy and sporulation where efficacy was comparable to undiluted cow urine. There is potential for the use of cow urine as a means of controlling Fusarium bark disease with other advantages being availability, low cost, and limited environmental damage. Timothy Gotora, Lawrence Masaka, and Marvelous Sungirai Copyright © 2014 Timothy Gotora et al. All rights reserved. Determining Critical Soil pH for Sunflower Production Sun, 06 Jul 2014 00:00:00 +0000 Soil acidity has become a major yield-limiting factor in cropping systems of the Southern Great Plains, in which winter wheat (Triticum aestivum L.) is the predominant crop. Sunflower (Helianthus annuus L.) is a strong rotational crop with winter wheat due to its draught and heat tolerance. However, the effects of low soil pH on sunflower productivity have not been explored. The objective of this study was to determine the critical soil pH and aluminum concentration () for sunflower. Sunflower was grown in a randomized complete block design with three replications of a pH gradient ranging from 4.0 to 7.0 at three locations with varying soil types. Soil pH was altered using aluminum sulfate (Al2(SO4)3) and hydrated lime (Ca(OH)2). Plant height, vigor, and survivability were all negatively affected by soil acidity. Sunflower yield was reduced by 10% at or below soil pH 4.7 to 5.3 dependent upon location and soil type. Levels of above 6.35 mg kg−1 reduced seed yield by 10% or greater. We concluded that sunflower may serve as a better rotational crop with winter wheat under acidic conditions when compared to other adaptable crops. Apurba Sutradhar, Romulo P. Lollato, Katy Butchee, and Daryl B. Arnall Copyright © 2014 Apurba Sutradhar et al. All rights reserved. FAO-56 Penman-Monteith Daily from Linear Regression Calibrated Hargreaves Equation with Wind Terms in Tropics with Limited Data Mon, 02 Jun 2014 06:13:19 +0000 Hargreaves equation (HG), which lacks a wind speed () term, was modified, through a linear regression calibration method, into LHGu which has terms. LHGu is effectively a simplified method for approximating FAO-56 Penman-Monteith equation (FPM) daily reference evapotranspiration () in tropics with only temperature data. In LHGu, the “0.0023” constant term in HG was calibrated as a shifted power function of , and the calibration constant was parametrized as a quadratic function of . LHGu was developed using simulated constant data and historical temperature data for four sites in West Africa: Abidjan, Accra, Daloa, and Lome. LHGu matched FPM better than HG over a wide range of : for Accra, for range 0.5–6.0 m/s, the modified coefficient of efficiency, , varied narrowly (0.83–0.98) for LHGu but widely (0.14–0.95) for HG optimized for  m/s; the corresponding MBE ranges were −0.05–0.01 mm/d for LHGu and 0.02–0.63 mm/d for HG which cannot respond to varying daily . LHGu is useful for quickly computing practically accurate estimates of FPM for varying daily where only temperature data are available. Eric Kra Copyright © 2014 Eric Kra. All rights reserved. Effect of Methyl Jasmonate on Phytoalexins Biosynthesis and Induced Disease Resistance to Fusarium oxysporum f. sp. Vasinfectum in Cotton (Gossypium hirsutum L.) Wed, 28 May 2014 11:23:12 +0000 The effect of methyl jasmonate (MeJA) sprayed on cotton healthy leaves was evaluated in terms of inherent bioactive chemicals induction. The total phenolic content significantly increased after MeJA 5.0 mM treatments compared to the other tested concentrations (0; 2.5; 10; 15; 20 mM). Among the eleven phenolic compounds which were found except for ferulic acid, gossypetin, gossypol, 3-p-coumaroylquinic acid, and piceatannol were identified as major phenolic constituents of cotton. Their content also significantly increased after the MeJA treatment. In addition, gossypol increased 64 times compared to the control, in the 5.0 mM MeJA treatment. Furthermore, cichoric acid, chlorogenic acid, and pterostilbene are synthesized de novo in leaves of MeJA-treated plant. Treatment of cotton leaves with MeJA 5.0 mM followed 72 h of incubation hampered the expression of Fusarium wilt caused by Fusarium oxysporium f. sp. vasinfectum (FOV). MeJA efficiency was concentration and incubation time dependent. Disease severity on MeJA-treated leaves was significantly lower as compared to the control. Therefore, the high content of gossypetin, gossypol, 3-p-coumaroylquinic acid, ferulic acid, and piceatannol and the presence of cichoric acid, chlorogenic acid, and pterostilbene in plants treated with MeJA, contrary to the control, are essential to equip the cotton compounds with defences or phytoalexins against FOV. Yao Kouakou François Konan, Kan Modeste Kouassi, Kouakou Laurent Kouakou, Edmond Koffi, Koffi Nazaire Kouassi, Diabaté Sekou, Mongomaké Kone, and Tanoh Hilaire Kouakou Copyright © 2014 Yao Kouakou François Konan et al. All rights reserved. Temperature Effect on Yield and Yield Components of Different Rice Cultivars in Flowering Stage Sun, 18 May 2014 05:56:24 +0000 In order to study the effect of cold stress in flowering stage on yield and yield components of different rice cultivars, an experiment was performed as split plot factorial based on completely randomized design (CRD) in greenhouse of deputy of rice research institute of Iran (Amol) in 2010, in three repetitions. Treatment included 5 varieties as main factors that included cultivars of shirudi, fajr, local tarom, hybrid, and line 843. Two levels of temperatures (13°C, stress temperature) and (32°C, normal temperature, control) along with flowering stage were selected as two subfactors. Three seedlings were planted in each plot. The cold stress was done in flowering stage with holding pots at 13°C for 15 days. Results showed that low temperature had significant effect in level of 1 percent on all characters, such as the number of panicles, the length of panicle, and the number of full, empty, and total grains; as a result, yield had caused significant reduction. Interaction between temperature and varieties showed that most tolerant variety in relation to temperature stress along with least percentage yield (19%) is shirudi variety and the most sensitive one with most percentage of yield decrease (29%) was local tarom variety. R. Ghadirnezhad and A. Fallah Copyright © 2014 R. Ghadirnezhad and A. Fallah. All rights reserved. Control of Echinochloa sp. in the Irrigated Rice Crop Wed, 14 May 2014 12:02:00 +0000 The species of Echinochloa (barnyardgrass) stand out among major weeds infesting rice cropping and damages are variable depending on the weed population, rice cultivar, and management practices adopted by rice farmers. The objective of this work was to measure the control of barnyardgrass in rice cropping, cultivar Qualimax 1, due to the early times of flood irrigation, application times, and doses of penoxsulam. The experiment was conducted in the field, where the experimental design used a randomized block design with a split plot design with four replications. The treatments consisted of two application periods (early and late) of penoxsulam three times of irrigation start (1, 15 and 30 days after treatment application—(DAT)) and herbicide doses (0, 24, 36, 48 and 60 g ha−1). The herbicide penoxsulam revealed that combined with irrigation starting 15 days after herbicide application promoted efficient control of barnyardgrass. Luís Eduardo Panozzo, Dirceu Agostinetto, Pedro Valério Dutra de Moraes, Deivid Araújo Magano, Adilson Harter, and Luciana Barros Pinto Copyright © 2014 Luís Eduardo Panozzo et al. All rights reserved. Response of Winter Wheat Grain Yield and Phosphorus Uptake to Foliar Phosphite Fertilization Thu, 08 May 2014 11:18:34 +0000 One of the major problems that potentially hinders the use of foliar fertilization as a tool to improve nutrient use efficiency is the lack of effective formulations. A phosphite based product, Nutri-phite (3% N, 8.7% P, and 5.8% K) was used as model phosphite formulation for foliar application in winter wheat (Triticum aestivum L). Five field trials were established in the fall of 2009 and 2010 at Perkins, Perry, and Morrison, OK. Treatments encompassed the application of nitrogen (N) at 100 or 75% of crop need and phosphorus at 100 (P 100%) and 80% (P 80%) sufficiency with and without Nutri-phite. Nutri-phite was applied at one and/or two stages of wheat; GS 13 to 14 and GS 49 to 53 at the rate of 433 and 148 g ha−1 P and N, respectively. Grain yield was increased by Nutri-phite treatments, especially at Morrison. Grain P concentration of plots treated with two applications of Nutri-phite ranged from 13 to 55% more than the nontreated and standard NP received plots at Perkins in 2009/10 and Perry in 2010/11. Grain P uptake was increased due to application of Nutri-phite at Perkins in 2009/10 and Morrison and Perry in 2010/11. Combined over three year-locations, Nutri-phite increased grain P concentration by 11.6%. The higher grain P concentration of plots treated with Nutri-phite compared to the other treatments clearly demonstrates its potential in improving P status of wheat grain. Muaid S. Ali, Apurba Sutradhar, Ma Lourdes Edano, Jeffrey T. Edwards, and Kefyalew Girma Copyright © 2014 Muaid S. Ali et al. All rights reserved. Research Progress and Perspectives of Nitrogen Fixing Bacterium, Gluconacetobacter diazotrophicus, in Monocot Plants Wed, 07 May 2014 06:38:45 +0000 Gluconacetobacter diazotrophicus is a nitrogen fixing bacterium originally found in monocotyledon sugarcane plants in which the bacterium actively fixes atmosphere nitrogen and provides significant amounts of nitrogen to plants. This bacterium mainly colonizes intercellular spaces within the roots and stems of plants and does not require the formation of the complex root organ like nodule. The bacterium is less plant/crop specific and indeed G. diazotrophicus has been found in a number of unrelated plant species. Importantly, as the bacterium was of monocot plant origin, there exists a possibility that the nitrogen fixation feature of the bacterium may be used in many other monocot crops. This paper reviews and updates the research progress of G. diazotrophicus for the past 25 years but focuses on the recent research development. N. Eskin, K. Vessey, and L. Tian Copyright © 2014 N. Eskin et al. All rights reserved. Promoting Agricultural Research and Development to Strengthen Food Security in South Asia Tue, 06 May 2014 06:44:24 +0000 This study aims to highlight the status of agricultural R&D in South Asia and contends that creating an effective agricultural research and innovation systems is a vital element to ensure food security in this region. South Asia is home to around one-fourth of mankind and houses the largest proportion of undernourished people in the world. Despite a period of marked economic growth averaging 6% a year over the past two decades, it remains the world's second poorest region contributing a mere 2.2% in global annual GDP. Agriculture is the mainstay of South Asian economy employing around 60% of the total workforce and generating around 20% of total GDP. South Asia has the recognition of being the second most food-insecure region next only to sub-Saharan Africa. Though there is growing evidence that technological innovation has a key role to play in increasing agricultural production and strengthening food security, agricultural research and development (R&D) sector has failed to garner sufficient attention till now. This study also depicts the current situation of food security in South Asia and illustrates how agricultural education and innovation hold the master key to solve the food security issues for the world's most densely populated region. Ghose Bishwajit Copyright © 2014 Ghose Bishwajit. All rights reserved. Apple Pollination Biology for Stable and Novel Fruit Production: Search System for Apple Cultivar Combination Showing Incompatibility, Semicompatibility, and Full-Compatibility Based on the S-RNase Allele Database Wed, 30 Apr 2014 07:05:33 +0000 Breeding and cultivation of new apple cultivars are among the most attractive and important issues for apple researchers. As almost all apple cultivars exhibit gametophytic self-incompatibility (GSI), cross-pollination between genetically different cultivars and species is essential not only for stable fruit production, but also for breeding of new cultivars. For cross-pollination by insect or hand pollination, pollen viability and pistil fertility are key factors, but also the mechanism of GSI has to be taken into account. This paper reviews the germination rate of pollen after storage in different conditions, at different periods of flowering, and in combination with pistil fertility and cross-compatibility among wild-, crab-, and cultivated apples. Furthermore, suitable cultivar combinations for new attractive apple cultivars based on GSI are explored. Especially, details about S-genotypes of apple cultivars, which are present in recent cultivar catalogues, are introduced together with a newly established on-line searchable database of S-genotypes of cultivars, wild apples and crab apples that shows incompatibility, semicompatibility, and full-compatibility. Shogo Matsumoto Copyright © 2014 Shogo Matsumoto. All rights reserved. Rice Breeding for High Grain Yield under Drought: A Strategic Solution to a Complex Problem Mon, 28 Apr 2014 09:06:44 +0000 Drought is one of the major abiotic stresses that affect rice production in rainfed areas. Recent trends in climate change have predicted a further increase in drought intensity, making the development of new drought-tolerant rice cultivars critical to sustain rice production in this ecosystem. The use of grain yield as a selection criterion at the International Rice Research Institute (IRRI), through proper population development and precise phenotyping techniques, has allowed the development of several high-yielding rice cultivars that have been released in major rainfed rice-growing areas. This strategy has also allowed the identification of several major quantitative trait loci (QTLs) that show large effects under drought across environments and genetic backgrounds. These QTLs are being pyramided together to develop drought-tolerant versions of popular drought-susceptible varieties. The near-isogenic lines (NILs) developed can replace the popular, high-yielding but drought-susceptible varieties in rainfed areas prone to drought. Additionally, these NILs serve as suitable genetic material for the study of molecular and physiological mechanisms underlying these QTLs. This may provide a better understanding of plant functions responsible for high grain yield under drought and lead to the identification of new traits and genes. Shalabh Dixit, Anshuman Singh, and Arvind Kumar Copyright © 2014 Shalabh Dixit et al. All rights reserved. Weed Management in Spring Seeded Barley, Oats, and Wheat with Prosulfuron Mon, 07 Apr 2014 13:36:58 +0000 A limited number of preplant (PP) herbicides are available for spring seeded cereals in Ontario. Six field trials were conducted at the Huron Research Station, Exeter, Ontario, over a two-year period (Exeter, 2010 and 2011) to evaluate glyphosate, prosulfuron, and glyphosate plus prosulfuron applied PP for weed management in spring seeded no-till barley, oats, and wheat. There was no injury in barley, oats, and wheat with glyphosate, prosulfuron, and glyphosate plus prosulfuron applied preplant at the rates evaluated at 1, 2, and 4 weeks after crop emergence. Prosulfuron provided 49–99% control of AMBEL, 28% or less control of CONAR, 31–94% control of POLCO, 49–98% control of SINAR, and 46–79% control of SONAR. Prosulfuron in combination with glyphosate provided 73–98% control of AMBEL, less than 43% control of CONAR, 39–94% control of POLCO, 63–98% control of SINAR, and 60–85% control of SONAR. Prosulfuron reduced density of AMBEL 76% and SINAR 93% but had no significant effect on density of CONAR, POLCO, or SONAR. Prosulfuron in combination with glyphosate reduced biomass of AMBEL as much as 96% and SINAR 98% but had no significant effect on biomass of CONAR, POLCO, or SONAR. Yield of barley, oats, and wheat was not affected with glyphosate, prosulfuron, and glyphosate plus prosulfuron at the rates evaluated. Nader Soltani, Lynette R. Brown, Todd Cowan, and Peter H. Sikkema Copyright © 2014 Nader Soltani et al. All rights reserved. Effect of Preplant Irrigation, Nitrogen Fertilizer Application Timing, and Phosphorus and Potassium Fertilization on Winter Wheat Grain Yield and Water Use Efficiency Thu, 03 Apr 2014 11:48:31 +0000 Preplant irrigation can impact fertilizer management in winter wheat. The objective of this study was to evaluate the main and interactive effects of preplant irrigation, N fertilizer application timing, and different N, P, and K fertilizer treatments on grain yield and WUE. Several significant two-way interactions and main effects of all three factors evaluated were observed over four growing seasons for grain yield and WUE. These effects could be described by differences in rainfall and soil moisture content among years. Overall, grain yield and WUE were optimized, if irrigation or adequate soil moisture were available prior to planting. For rain-fed treatments, the timing of N fertilizer application was not as important and could be applied before planting or topdressed without much difference in yield. The application of P fertilizer proved to be beneficial on average years but was not needed in years where above average soil moisture was present. There was no added benefit to applying K fertilizer. In conclusion, N and P fertilizer management practices may need to be altered yearly based on changes in soil moisture from irrigation and/or rainfall. Jacob T. Bushong, D. Brian Arnall, and William R. Raun Copyright © 2014 Jacob T. Bushong et al. All rights reserved. Assessing the Spectral Separability of Flue Cured Tobacco Varieties Established on Different Planting Dates and under Varying Fertilizer Management Levels Wed, 26 Mar 2014 09:29:08 +0000 The NDVI was used to discriminate tobacco variety, assess fertilizer levels, and determine the impact of planting date on separating crops. A split plot design with four planting dates, September, October, November, and December, as main plots, variety as subplot, and fertilizer treatments as sub-subplots was used. Radiometric measurements were taken from 5 m × 5 m sampling plots, using a multispectral radiometer. The September, October, and November crops had significant variety x fertilizer treatment differences () from the age of 10 weeks. T 66 and KRK26 varieties had similar () NDVI values and these were greater () than those for K E1. The 100% and the 150% fertilizer treatments were similar () and both were greater () than the 50% fertilizer treatments. All of the fertilizer and variety treatments at the December planting dates had similar reflectance characteristics (), which were lower () than the September and October planting dates. The results showed that planting dates, varieties, and fertilizer levels could be distinguished using spectral data. Weeks 10-11 and 15 after the start of the experiment were optimal for separating the planting date effect. Ezekia Svotwa, Anxious J. Masuka, Barbara Maasdorp, and Amon Murwira Copyright © 2014 Ezekia Svotwa et al. All rights reserved. Estimating Rice Yield under Changing Weather Conditions in Kenya Using CERES Rice Model Wed, 26 Mar 2014 06:44:54 +0000 Effects of change in weather conditions on the yields of Basmati 370 and IR 2793-80-1 cultivated under System of Rice Intensification (SRI) in Mwea and Western Kenya irrigation schemes were assessed through sensitivity analysis using the Ceres rice model v 4.5 of the DSSAT modeling system. Genetic coefficients were determined using 2010 experimental data. The model was validated using rice growth and development data during the 2011 cropping season. Two SRI farmers were selected randomly from each irrigation scheme and their farms were used as research fields. Daily maximum and minimum temperatures and precipitation were collected from the weather station in each of the irrigation schemes while daily solar radiation was generated using weatherman in the DSSAT shell. The study revealed that increase in both maximum and minimum temperatures affects Basmati 370 and IR 2793-80-1 grain yield under SRI. Increase in atmospheric CO2 concentration led to an increase in grain yield for both Basmati and IR 2793-80-1 under SRI and increase in solar radiation also had an increasing impact on both Basmati 370 and IR 2793-80-1 grain yield. The results of the study therefore show that weather conditions in Kenya affect rice yield under SRI and should be taken into consideration to improve food security. W. O. Nyang’au, B. M. Mati, K. Kalamwa, R. K. Wanjogu, and L. K. Kiplagat Copyright © 2014 W. O. Nyang’au et al. All rights reserved. Evaluation of Green Manure Amendments for the Management of Fusarium Basal Rot (Fusarium oxysporum f.sp. cepae) on Shallot Tue, 04 Mar 2014 09:04:46 +0000 Shallot (Allium cepa L. var. ascalonicum) is the most traditional vegetable crop in Ethiopia. Shallot is susceptible to a number of diseases that reduce yield and quality, among which fusarium basal rot (FBR) caused by Fusarium oxysporum f.sp. cepae (Foc) is one of the most important yield limiting factors in Ethiopia. The present study was designed to evaluate the effectiveness of Brassica crops for the management of shallot FBR on shallot. The experiments were carried out at Debre Zeit Agricultural Research Center using cabbage (Brassica oleracea), garden cress (Lepidium sativum), Ethiopia mustard (B. carinata), and rapeseed (B. napus). The evaluations were done under in vitro and greenhouse conditions. Under in vitro test condition it was confirmed that extracts of Ethiopian mustard and rapeseed showed higher inhibition on the growth of Foc pathogen compared to control. Data on seedling emergence, plant height, plant stand, disease incidence, severity, cull bulbs, and bulb weight were collected in greenhouse experiment. The green manure amendments of rapeseed and Ethiopian mustard significantly reduced disease incidence by 21% and 30% and disease severity by 23% and 29%, respectively. However the plant emergency was not significantly different among treatments in greenhouse test. These results indicated that Ethiopian mustard and rapeseed crops have potential as green manure for the management of FBR disease of shallot crop. Assefa Sintayehu, Seid Ahmed, Chemeda Fininsa, and P. K. Sakhuja Copyright © 2014 Assefa Sintayehu et al. All rights reserved. Effect of Osmopriming Duration on Germination, Emergence, and Early Growth of Cowpea (Vigna unguiculata (L.) Walp.) in the Sudan Savanna of Nigeria Thu, 27 Feb 2014 09:26:32 +0000 Seed osmopriming could be a sustainable method to increase crop establishment, uniform emergence, and growth of plant on the field. Laboratory and field studies were carried out in 2010 cropping season at Usmanu Danfodiyo University, Sokoto, to study the effect of seed osmopriming duration on the germination, emergence, and growth of cowpea seeds. Treatments consisted of three osmopriming duration (soaking in 1% KNO3 salt for 6, 8, and 10 hrs), one hydroprimed control (10 hr), and an unprimed control. These five treatments were laid out in a completely randomized design (CRD) replicated four times. The results showed that osmopriming with KNO3 for different durations was at par but was superior to unprimed treatments in terms of seed germination, emergence, plant height, and dry matter accumulation at 3 weeks after sowing. From this study, it can therefore be concluded that seeds of cowpea could be primed (both hydro and osmopriming) for increased performance. However, osmopriming with KNO3 salt (soaked in 1% KNO3 salt solution and dried before sowing) for 6 hours could result in greater seed germination and seedling height than hydropriming. Ajit Singh, Rabi Dahiru, Mukhtar Musa, and Bello Sani Haliru Copyright © 2014 Ajit Singh et al. All rights reserved. Growth Rate and Yield of Two Tomato Varieties (Lycopersicon esculentum Mill) under Green Manure and NPK Fertilizer Rate Samaru Northern Guinea Savanna Thu, 20 Feb 2014 07:05:48 +0000 Field experiments were conducted in 2010-2011 and 2011-2012 dry seasons at the Research farm of the Institute for Agricultural Research, Samaru northern guinea savanna agro ecological zone of Nigeria to study growth rate and yield of tomato under green manure and NPK fertilizer rates. Treatment consisted of two tomato varieties (Roma VF and UC82B), four rates of NPK 15-15-15 fertilizer (0, 150, 300, and 450 kg ha−1), and three rates of green manure (0, 5, and 10 t ha−1), laid in a split-plot design with three replications. The variety and fertilizer constituted the main plot while green manure was allocated in subplot. Both varieties responded linearly in growth stages of 5 and 7 weeks after transplanting (WAT) on plant height, relative growth rate, and crop growth rate (CGR). However, UC82B proves superior over Roma VF on growth indices CGR at 5–7 WAT, net assimilation rate (NAR) at 7–9 WAT, and total fruit yield with 10.6% higher. Application of NPK fertilizer significantly increased growth such as plant height, crop dry weight, crop growth rate, and yield. Application between 250 and 280 kg ha−1 NPK fertilizers was found efficient for total fruit yield. A. S. Isah, E. B. Amans, E. C. Odion, and A. A. Yusuf Copyright © 2014 A. S. Isah et al. All rights reserved. Distribution of Glyphosate- and Thifensulfuron-Resistant Palmer Amaranth (Amaranthus palmeri) in North Carolina Tue, 11 Feb 2014 15:48:20 +0000 Glyphosate resistance in Palmer amaranth was first confirmed in North Carolina in 2005. A survey that year indicated 17 and 18% of 290 populations sampled were resistant to glyphosate and thifensulfuron, respectively. During the fall of 2010, 274 predetermined sites in North Carolina were surveyed to determine distribution of Palmer amaranth and to determine if and where resistance to fomesafen, glufosinate, glyphosate, and thifensulfuron occurred. Palmer amaranth was present at 134 sites. When mortality for each biotype was compared to a known susceptible biotype for each herbicide within a rate, 93 and 36% of biotypes were controlled less by glyphosate (840 g ae ha−1) and thifensulfuron (70 g ai ha−1), respectively. This approach may have underestimated resistance for segregating populations due to lack of homogeneity of the herbicide resistance trait and its contribution to error variance. When mortality and visible control were combined, 98% and 97% of the populations were resistant to glyphosate and the ALS inhibitor thifensulfuron, respectively, and 95% of the populations expressed multiple resistance to both herbicides. This study confirms that Palmer amaranth is commonly found across the major row crop production regions of North Carolina and that resistance to glyphosate and ALS-inhibiting herbicides is nearly universal. No resistance to fomesafen or glufosinate was observed. Amy H. Poirier, Alan C. York, David L. Jordan, Aman Chandi, Wesley J. Everman, and Jared R. Whitaker Copyright © 2014 Amy H. Poirier et al. All rights reserved. A Review on Recycling of Sunflower Residue for Sustaining Soil Health Tue, 04 Feb 2014 13:11:30 +0000 Modern agriculture is now at the crossroads ecologically, economically, technologically, and socially due to soil degradation. Critical analysis of available information shows that problems of degradation of soil health are caused due to imbalanced, inadequate and promacronutrient fertilizer use, inadequate use or no use of organic manures and crop residues, and less use of good quality biofertilizers. Although sizeable amount of crop residues and manure is produced in farms, it is becoming increasingly complex to recycle nutrients, even within agricultural systems. Therefore, there is a need to use all available sources of nutrients to maintain the productivity and fertility at a required level. Among the available organic sources of plant nutrients, crop residue is one of the most important sources for supplying nutrients to the crop and for improving soil health. Sunflower is a nontraditional oil seed crop produced in huge amount of crop residue. This much amount of crop residues is neither used as feed for livestock nor suitable for fuel due to low energy value per unit mass. However, its residue contains major plant nutrients in the range from 0.45 to 0.60% N, 0.15 to 0.22% P, and 1.80 to 1.94% K along with secondary and micronutrients, so recycling of its residue in the soil may be one of the best alternative practices for replenishing the depleted soil fertility and improving the physical, chemical, and biological properties of the soil in the present era of production. However, some researchers have reported allelopathic effects of sunflower residue on different crops. So, selection of suitable crops and management practices may play an important role to manage the sunflower residue at field level. Subhash Babu, D. S. Rana, G. S. Yadav, Raghavendra Singh, and S. K. Yadav Copyright © 2014 Subhash Babu et al. All rights reserved. Evaluation of Agronomic Management Practices on Farmers’ Fields under Rice-Wheat Cropping System in Northern India Thu, 30 Jan 2014 10:02:35 +0000 Rice (Oryza sativa L.)-wheat (Triticum aestivum L. emend. Fiori and Paol.) is the most important two crops a year intensive rice based cropping system of Asia. Agronomic management is the most important input for getting potential yield and high net returns in any crop or crop sequence. Most of the farmers used to grow old varieties of rice and wheat without any row arrangement. Fertilization is mainly limited to nitrogenous fertilizer only. Therefore, the present study was undertaken to find out the effect of different agronomic management practices on productivity and economics of rice-wheat system at farmers’ fields. Inclusion of improved variety in rice and wheat incurred additional cost of $52/ha and provided additional return of $101/ha, whereas sowing/transplanting of rice and wheat in lines incurred additional cost of $30/ha and resulted in additional returns of $146/ha. Balanced fertilization incurred additional cost of $38 over the imbalanced fertilization and provided additional returns of $180/ha. Recommended package of practices (improved variety, line sowing/transplanting and balanced fertilization) incurred additional cost of cultivation of $120/ha over the farmers’ practice and achieved additional net returns of $426/ha. Dinesh Kumar Singh, Purushottam Kumar, and A. K. Bhardwaj Copyright © 2014 Dinesh Kumar Singh et al. All rights reserved. Response of Dry Bean to Sulfentrazone Plus Imazethapyr Thu, 30 Jan 2014 09:37:51 +0000 Field studies were conducted in 2010 and 2011 at the Huron Research Station, Exeter, Ontario and from 2009 to 2011 at the University of Guelph Ridgetown Campus, Ridgetown, Ontario to evaluate the sensitivity of four market classes of dry bean to sulfentrazone applied preemergence at 105, 140, and 280 g ai/ha alone and in combination with imazethapyr at 37.5 g ai/ha. At 1 week after emergence (WAE), sulfentrazone alone or in combination with imazethapyr at all doses evaluated caused no significant visible injury in dry bean. At 2 WAE, sulfentrazone alone caused 1–11, 1–11, 1–5, and 3–19% visible injury, and sulfentrazone + imazethapyr caused 3–11, 2–10, 2–5, and 4–20% visible injury in black, cranberry, kidney, and white bean, respectively. At 4 WAE, sulfentrazone alone caused 1–7, 1–7, 0–4, and 1–16% visible injury and sulfentrazone + imazethapyr caused 1–8, 1–5, 1–3, and 2–14% visible injury in black, cranberry, kidney, and white bean, respectively. Sulfentrazone PRE caused slightly greater injury in black and white bean compared to cranberry and kidney bean. Generally, crop injury with sulfentrazone at rates up to 140 g ai/ha alone and in combination with imazethapyr at 37.5 g ai/ha was minimal with no adverse effect on plant height, shoot dry weight, seed moisture content, and yield. Based on these results, there is potential for preemergence application of sulfentrazone at rates up to 140 g ai/ha alone or in combination with imazethapyr at 37.5 g ai/ha in black, cranberry, kidney and white bean. Nader Soltani, Christy Shropshire, and Peter H. Sikkema Copyright © 2014 Nader Soltani et al. All rights reserved. Development of an Effective Nonchemical Method against Plasmodiophora brassicae on Chinese Cabbage Wed, 29 Jan 2014 00:00:00 +0000 Clubroot disease, caused by Plasmodiophora brassicae, is a serious soil-borne disease of crucifer worldwide, and it can significantly reduce yield and quality. Although some agrochemicals have been used to manage clubroot and can provide effective control, increasing use of chemical inputs causes several negative effects. In this study, using Chinese cabbage (Brassica rapa L. subsp. chinensis) as the test crop, we developed an effective nonchemical method that would protect the roots against P. brassicae infection by using a combination heat treatment and a cocktail of biocontrol agents. The data showed that this method could cause 91.7% inhibition of P. brassicae infection. The average height of plants (13.5 cm) using this method was about twice higher than that in control group (6.7 cm), and the average plant weight (3.19 g) was about three times increased compared to that in control set (1.23 g). Yu Gao and Guanghui Xu Copyright © 2014 Yu Gao and Guanghui Xu. All rights reserved. Potential of Cowpea Variety Mixtures to Increase Yield Stability in Subsistence Agriculture: Preliminary Results Thu, 23 Jan 2014 16:24:46 +0000 Cowpea Vigna unguiculata (L.) Walp. is an important leafy vegetable and grain legume in Uganda. Unlike in commercial agriculture, where variety mixtures are known to give higher and more stable yields, the performance of cowpea variety mixtures in subsistence agriculture is little known. Mixtures containing up to four cowpea varieties were subjected to all possible 2-way, 3-way, and 4-way combinations. These cowpea varieties and mixtures were grown at three locations in Soroti and Kumi districts in order to assess the relative mixture effect, defined as: Mixture effect (%) = (mixture yield − pure line component average)/pure line component average × 100. Yield data was subjected to one-way ANOVA using the GLM procedure of SYSTAT. PLABSTAT was used to generate ecovalence () values as a measure of stability with low ecovalence values indicating higher stability. The total cowpea dry matter (DM) yield was in the range of  3.7–6.7 g/m2 (leaf) and 12.1–36.7 g/m2 (grain), respectively. Mixture effects were between  −9.3–14.0% (leaf) and −30.3–21.9% (grain). Yield stability spanned   = 0.06–5.30 (leaf) and = 4.45–894.84 (grain). The results suggested that yields of cowpea variety mixtures grown in marginal environments were more stable than of single varieties but not all mixtures yielded more than single varieties. Joshua S. Okonya and Brigitte L. Maass Copyright © 2014 Joshua S. Okonya and Brigitte L. Maass. All rights reserved. Irrigated Soybean Leaf Photosynthesis in the Humid Subtropical Midsouth Thu, 23 Jan 2014 08:52:32 +0000 Photosynthesis (CER (μmol CO2 s−1)), stomatal conductance (), and intercellular [CO2] () of soybean (Glycine max L. Merr.) grown using the early soybean production system (ESPS) of the midsouth were determined. Three irrigated cultivars were grown using ESPS on Bosket (Mollic Hapludalfs) and Dundee (Typic Endoaqualf) soils in 2011 and 2012 at Stoneville, MS. Single leaf CER, , and were determined at growth stages R3, R4, and R5 using decreasing photosynthetic photon flux densities (PPFD, μmol m−2 s−1) beginning at 2000 PPFD and decreasing by 250 PPFD increments to 250 PPFD. Photosynthesis changes fit a quadratic polynomial for all fixed variables and range from ~6.0 and 9.0 CER at 250 PPFD and ~22.0 to 28.0 CER at 2000 PPFD. No cultivar differences in CER, , or were noted at any growth stage or site either year. In 2012, CER, , and were lower when measured at R5 than the two previous growth stages, which was not observed in 2011. The R5 sampling in 2012 had accumulated 39 to 70 more growing degree units at 10°C base temperature (GDU 10’s) than in 2011 and were likely more mature. Increased soybean yields from ESPS appear not to result from higher leaf CER. H. Arnold Bruns Copyright © 2014 H. Arnold Bruns. All rights reserved. Moisture and Salinity Stress Induced Changes in Biochemical Constituents and Water Relations of Different Grape Rootstock Cultivars Mon, 20 Jan 2014 11:20:26 +0000 Ten grape rootstocks were subjected to moisture and salinity stress in two separate experiments. The influence of these stresses on gas exchange, water relation, and biochemical parameters was monitored at various stages of stress cycle. Both stresses indicated significant changes in the physiological and biochemical parameters studied. Some biochemical constituents increased by several folds in few rootstock cultivars which also recorded increased osmotic potential suggesting their role in osmotic adjustment. Some of the rootstock cultivars such as 110R, 1103P, 99R, Dogridge, and B2/56 recorded increased phenolic compounds under stressed conditions. The same rootstock also recorded increased water use efficiency. The increased accumulation of phenolic compounds in these cultivars may indicate the possible role of phenolic compounds as antioxidants for scavenging the reactive oxygen species generated during abiotic stresses thus maintaining normal physiological and biochemical process in leaves of resistant cultivars. Satisha Jogaiah, Sahadeo D. Ramteke, Jagdev Sharma, and Ajay Kumar Upadhyay Copyright © 2014 Satisha Jogaiah et al. All rights reserved. Influence of Priming Duration on the Performance of Amaranths (Amaranthus cruentus L.) in Sokoto Semiarid Zone of Nigeria Sun, 19 Jan 2014 08:18:23 +0000 Two field trials were conducted during the 2012 cropping season at the Fruits and Vegetable Teaching and Research Farm of the Department of Crop Science, Usman Danfodiyo University, Sokoto (located on latitude N-N and longitude -), to evaluate the effect of priming duration on the growth and yield of amaranth. Treatments consisted of four priming durations (2, 4, 6, and 8 hours) and control (where no priming was applied). The treatments were laid out in a completely randomized design (CRD) replicated three times for the germination test and randomized complete block design (RCBD) for the field trial. Data were collected on days to 50% germination, percentage germination, days to 50% emergence, and percentage emergence. Results revealed significant effect of priming duration on days to 50% germination, percentage germination, and days to 50% emergence. Soaking seeds for 2 hours reduced the number of days to 50% germination and emergence and also recorded higher germination. Thus, from the findings of this study, it could be concluded that priming amaranth seeds for 2 hours could be applied to enhance amaranth production. Mukhtar Musa, Ajit Singh, and Aminu Aliyu Lawal Copyright © 2014 Mukhtar Musa et al. All rights reserved. Exchange Characteristics of Lead, Zinc, and Cadmium in Selected Tropical Soils Thu, 16 Jan 2014 14:34:44 +0000 Conducting binary-exchange experiments is a common way to identify cationic preferences of exchangeable phases in soil. Cation exchange reactions and thermodynamic studies of Pb2+/Ca2+, Cd2+/Ca2+, and Zn2+/Ca2+ were carried out on three surface (0–30 cm) soil samples from Adamawa and Niger States in Nigeria using the batch method. The physicochemical properties studies of the soils showed that the soils have neutral pH values, low organic matter contents, low exchangeable bases, and low effective cation exchange capacity (mean: 3.27 cmolc kg−1) but relatively high base saturations (≫50%) with an average of 75.9%. The amount of cations sorbed in all cases did not exceed the soils cation exchange capacity (CEC) values, except for Pb sorption in the entisol-AD2 and alfisol-AD3, where the CEC were exceeded at high Pb loading. Calculated selectivity coefficients were greater than unity across a wide range of exchanger phase composition, indicating a preference for these cations over Ca2+. The values obtained in this work were all positive, indicating that the exchange reactions were favoured and equally feasible. These values indicated that the Ca/soil systems were readily converted to the cation/soil system. The thermodynamic parameters calculated for the exchange of these cations were generally low, but values suggest spontaneous reactions. Tope O. Bolanle-Ojo, Abiodun D. Joshua, Opeyemi A. Agbo-Adediran, Ademola S. Ogundana, Kayode A. Aiyeyika, Adebisi P. Ojo, and Olubunmi O. Ayodele Copyright © 2014 Tope O. Bolanle-Ojo et al. All rights reserved.