1,327 research outputs found
Evaluation of Weed Management Practices for Rain‐Fed Safflower Production in a Semiarid Mediterranean Environment
No full textSince safflower (Carthamus tinctorius L.) has slow early growth, effective early weed control is essential. The objective of this study was to investigate the effectiveness of various nonchemical and chemical practices for weed management in rain-fed safflower. Field experiments were performed for three production years in the Bekaa Valley of Lebanon. Six weed management practices were tested: delayed sowing, delayed sowing with interrow cultivation, normal sowing with interrow cultivation, preermergence herbicide, hand weeding, and the normal sowing weedy check. Averaged over 1999-2000 and 2000-2001, weeds were absent with herbicide application and there were as few as andlt;4 weed plants m-2 in delayed sowing with interrow cultivation and hand weeding. Interrow cultivation under normal sowing, herbicide application, and hand weeding gave higher safflower seed and straw yields than the weedy check. Over the three production years, only interrow cultivation under normal sowing and hand weeding produced higher safflower seed and straw yields than the weedy check. In conclusion, interrow cultivation under normal sowing could be considered the best practice; application of pendimethalin and pronamide was also superior to delay sowing. Copyright © 2008 by the American Society of Agronomy. All rights reserved.BEG A, 1993, STATUS POTENTIAL SOM; HAIDAR MA, 2000, 7 AR C PLANT PROT 22, P31; KAFTKA SR, 1998, PUBL U CALIFORNIA; Knowles P. F., 1976, Evolution of crop plants., P31; MCINTOSH MS, 1983, AGRON J, V75, P153; MONTEMURRO P, 1997, SAFFLOWER MULTIPURPO, P132; Mundel HH, 1992, SAFFLOWER PRODUCTION, P35; RYAN J, 1980, PUBL AM U BEIRUT, V64; SALERA E, 1997, SAFFLOWER MULTIPURPO, P136; Yau SK, 2007, EUR J AGRON, V26, P249, DOI 10.1016-j.eja.2006.10.004; Yau SK, 2004, EXP AGR, V40, P453, DOI 10.1017-S0014479704002121; Yau SK, 2003, AGRON J, V95, P821; Yau S.K., 1999, SESAME SAFFLOWER NEW, V14, P9722
Boron Toxicity Tolerance in Crops: A Viable Alternative to Soil Amelioration
No full textResearch on the problems of excessive soil B has increased considerably in the past two decades, especially in the dry areas of the world such as the Mediterranean region and parts of Australia. The objectives of this review are to promote awareness of the widespread occurrence and importance of B toxicity (BT) in dry areas, and to review the availability of BT-tolerant germplasm and progress in breeding cultivars with BT tolerance. The importance of BT was not adequately recognized until the 1980s, when scientists discovered that BT caused significant crop yield reductions in South Australia. We offer several reasons for this belated awareness before describing the areas reported to have high-B soils in the world and reviewing the occurrence of two contrasting types of BT symptoms. In the field, BT in crops usually is more prominent after drought, indicating that both BT and drought tolerance are needed in crops for dry areas having high levels of subsoil B. The interaction of BT with salinity and the levels of other nutrients such as Zn and N are also discussed. As it is neither practical nor easy to detoxify high-B soil by agronomic means in most circumstances, selecting or breeding crop cultivars with high BT tolerance is the only practical approach to increase yields on high-B soils. Extensive surveys of germplasm in different crops have been performed, and a list of some BT-tolerant lines or cultivars is presented. Finally, we review the progress in breeding for BT tolerance, which has been achieved with varying success in several common crops. We believe that the shift from soil intervention to plant adaptation to solve an intractable crop nutrition constraint represents a new paradigm in the agronomic sciences. © Crop Science Society of America. All rights reserved.Adcock D, 2007, AUST J EXP AGR, V47, P1245, DOI 10.1071-EA06250; ALKHAFAJI A, 1995, ACCOMPLISHMENTS FUTU, P204; Amadi T.H., 1989, ZANCO, V2, P19; ASHWORTH LJ, 1985, PHYTOPATHOLOGY, V75, P1084; Avci Muzaffer, 2005, Turkish Journal of Agriculture and Forestry, V29, P377; BAGHERI A, 1994, EUPHYTICA, V75, P9, DOI 10.1007-BF00024526; BAGHERI A, 1992, PLANT SOIL, V146, P261, DOI 10.1007-BF00012020; BERGER KC, 1962, J AGR FOOD CHEM, V10, P178, DOI 10.1021-jf60121a005; BINGHAM FT, 1987, PLANT SOIL, V97, P345, DOI 10.1007-BF02383224; BRADFORD GORDON R., 1966, P33; Brady N. C., 1999, NATURE PROPERTY SOIL; BRANSON RL, 1976, SOIL PLANT TISSUE TE, P42; Brennan RF, 2004, J PLANT NUTR, V27, P411, DOI 10.1081-PLN-120028870; Brown PH, 1999, J AM SOC HORTIC SCI, V124, P347; Brown PH, 1996, ANN BOT-LONDON, V77, P497, DOI 10.1006-anbo.1996.0060; Brown P. H., 1998, Better Crops with Plant Food, V82, P28; Brown PH, 1998, BOT ACTA, V111, P331; CAKMAK I, 1996, P 5 INT WHEAT C ANK, P279; CARTWRIGHT B, 1986, AUST J AGR RES, V37, P351, DOI 10.1071-AR9860351; CARTWRIGHT B, 1984, AUST J SOIL RES, V22, P321; Chantachume Y, 1995, PLANT SOIL, V177, P249, DOI 10.1007-BF00010131; CHANTACHUME Y, 1993, P 10 AUSTR PLANT BRE, V2, P18; CHAUHAN RPS, 1981, J AGR SCI, V97, P75; CHAUHAN RPS, 1984, J AGR SCI, V102, P237; Choe J. S., 1986, Journal of the Korean Society for Horticultural Science, V27, P149; Christensen JJ, 1934, PHYTOPATHOLOGY, V24, P726; COOPER D, 2004, IMPROVING DURUM WHEA; COOPER WC, 1955, J RIO GRANDE VALLEY, V9, P86; Dobermann A., 2000, HDB SERIES POTASH PH; EATON FM, 1935, USDA TECH B, V448; EGLINTON J, 2004, PLANT BREEDING TOUGH; ELMOTAIUM R, 1994, J AM SOC HORTIC SCI, V119, P1169; Elseewi AA, 1974, ALEXANDRIA J AGR RES, V22, P463; GRAHAM RD, 1987, SOIL SCI SOC AM J, V51, P652; GUPTA UC, 1979, ADV AGRON, V31, P273; GUPTA UC, 1985, CAN J SOIL SCI, V65, P381; Gupta U. C., 1993, BORON ITS ROLE CROP; GUPTA UC, 1976, SOIL SCI SOC AM J, V40, P723; Gupta UC, 1998, COMMUN SOIL SCI PLAN, V29, P1491, DOI 10.1080-00103629809370045; HANSEN CJ, 1948, P AM SOC HORTIC SCI, V51, P239; HARMSEN K, 1985, MICRONUTRIENTS TROPI, P1; Hobson K, 2006, EUPHYTICA, V151, P371, DOI 10.1007-s10681-006-9159-7; HOLLOWAY RE, 1992, AUST J AGR RES, V43, P987, DOI 10.1071-AR9920987; HUTCHINS.GL, 1969, SOIL SCI, V108, P217, DOI 10.1097-00010694-196909000-00011; JAMJOD S, 1994, P 7 ASS WHEAT BREED, P225; JENKIN MJ, 1991, SHORT PAPERS, V1, P556; Kaur S, 2006, PLANT SOIL, V285, P115, DOI 10.1007-s11104-006-0063-7; Keren R., 1985, ADV SOIL SCI, V1, P229; KHAN ZD, 1979, AGRON J, V71, P79; Leyshon A.J., 1993, BORON ITS ROLE CROP; LI CJ, 2005, PLANT NUTR FOOD SECU; Marschner H., 1986, MINERAL NUTR HIGHER; MCDONALD G, 2002, EYRE PENINSULA FARMI, P26; MOODY DB, 1988, P 7 INT WHEAT GEN S, V2, P859; MORTVEDT JJ, 1991, SSSA BOOK SER, V4; NABLE RO, 1988, PLANT SOIL, V112, P45, DOI 10.1007-BF02181751; Nable RO, 1997, PLANT SOIL, V193, P181, DOI 10.1023-A:1004272227886; Nuttall JG, 2006, AUST J EXP AGR, V46, P1507, DOI 10.1071-EA04264; OERTLI J. J., 1960, AGRON JOUR, V52, P530; Paull J. G., 1993, P 8 INT WHEAT GEN S; PAULL JG, 1991, EUPHYTICA, V55, P217, DOI 10.1007-BF00021242; PAULL JG, 1988, EUPHYTICA, V39, P137, DOI 10.1007-BF00039866; PAULL JG, 1992, AUST J AGR RES, V43, P203, DOI 10.1071-AR9920203; RASHID A, 1994, COMMUN SOIL SCI PLAN, V25, P2883, DOI 10.1080-00103629409369232; RATHJEN AJ, 1995, AUST J EXP AGR, V35, P673, DOI 10.1071-EA9950673; RAVIKOVITCH S., 1961, SOIL SCI, V92, P85, DOI 10.1097-00010694-196108000-00002; RILEY MM, 1994, J PLANT NUTR, V17, P1721, DOI 10.1080-01904169409364842; RYAN J, 1977, PLANT SOIL, V47, P253, DOI 10.1007-BF00010386; Ryan J, 1998, SOIL TILL RES, V45, P407, DOI 10.1016-S0933-3630(97)00037-8; Salinas R., 1986, J HORTIC SCI, V61, P323; SALINAS RA, 1981, J PLANT NUTR, V4, P205; SALINAS RM, 1987, AGROCHIMICA, V31, P489; SEPASKHAH AR, 1994, J PLANT NUTR, V17, P155, DOI 10.1080-01904169409364716; Sillanpaa M., 1982, MICRONUTRIENTS NUTR; SINGH JP, 1990, FERT RES, V24, P105, DOI 10.1007-BF01073228; Sotiropoulos TE, 1999, SCI HORTIC-AMSTERDAM, V81, P443, DOI 10.1016-S0304-4238(99)00028-X; SOTIROPOULOS TE, 1997, ACTA HORTIC, V444, P243; SWIETLIK D, 1995, J PLANT NUTR, V18, P1191, DOI 10.1080-01904169509364972; Torun Ayfer A., 2006, Turkish Journal of Agriculture and Forestry, V30, P49; Torun A, 2001, J PLANT NUTR, V24, P1817, DOI 10.1081-PLN-100107314; Torun B, 2003, J PLANT NUTR, V26, P1735, DOI 10.1081-PLN-120023279; WAYNE R, 1986, RURAL RES, V130, P25; WOODBRIDGE C. G., 1955, CANADIAN JOUR AGRIC SCI, V35, P282; Yau SK, 2002, EUPHYTICA, V123, P307, DOI 10.1023-A:1015047523382; YAU SK, 1998, SEWANA S EUR W AS N, P174; Yau SK, 2001, COMMUN SOIL SCI PLAN, V32, P379, DOI 10.1081-CSS-100103014; Yau S.K., 1997, BORON SOILS PLANTS, P117; Yau SK, 1997, AUST J AGR RES, V48, P945, DOI 10.1071-A96144; YAU SK, 1994, BARLEY NEWSL, V37, P110; YAU SK, 1996, IMPORTANCE GENOTYPIC; YAU SK, 1997, ACCOMPLISHMENTS FUTU, P208; Yau SK, 2000, GENET RESOUR CROP EV, V47, P55, DOI 10.1023-A:1008733106108; YAU SK, 1995, ANN WHEAT NEWSL, V41, P204; Yau SK, 1997, AUST J AGR RES, V48, P951, DOI 10.1071-A96145; YAU SK, 1995, EUPHYTICA, V83, P185, DOI 10.1007-BF01678128; YAU SK, 1994, ANN WHEAT NEWSL, V40, P204; YAU SK, 2004, INT S AD PLANTS WAT, P59; Yau SK, 2002, AUST J AGR RES, V53, P347, DOI 10.1071-AR00154; YAU SK, 1995, BARLEY NEWSL, V38, P124; YAU SK, 1996, 2 INT CROP SCI C 17, P13822312
Differential impacts of climate variability on yields of rainfed barley and legumes in semi-arid Mediterranean conditions
No full textClimate change has emerged as a major concern for crop production. This study used a field experiment to examine the differential yield responses of barley, lentil, common vetch, and bitter vetch to weather in the Mediterranean region. Crops were grown in a 10-year rotation trial in Lebanon. Precipitation and temperature were used as explanatory variables in simple linear correlation and standardized multiple-regression analyses. Grain yields were not correlated with annual precipitation. Barley grain yield was correlated positively with precipitation from March to May (r = 0.70) and the rainfall distribution index (r = 0.71), but negatively with mean May temperature (r = -0.62) and absolute minimum temperature in January (r = -0.91). Unlike barley, legume grain yield was not correlated with any rainfall parameters. Common vetch grain yield was negatively correlated with mean May temperature (r = -0.68). Grain yield of the two vetches were also correlated negatively with the absolute minimum temperature in January, but grain yield of lentil was not correlated with any weather variable. Standardized multiple-regression analyses showed that mean May temperature had the strongest influence on grain yield of barley, lentil, and common vetch, indicating that, under climate change, higher temperature may have a more deleterious effect on grain yield than lower rainfall. The negative correlation between common vetch and barley grain yields and temperature in May suggests that early sowing to induce earlier flowering and maturity to escape the hot summer may be an option to increase common vetch and barley grain yields. © 2013 Copyright © 2013 Taylor and Francis.Abd El Monein AM, 1988, J AGR SCI, V111, P295; Adcock D, 2007, AUST J EXP AGR, V47, P1245, DOI 10.1071-EA06250; BLUM A, 1990, AUST J AGR RES, V41, P799, DOI 10.1071-AR9900799; BRING J, 1994, AM STAT, V48, P209, DOI 10.2307-2684719; CECCARELLI S, 1991, EUPHYTICA, V56, P169, DOI 10.1007-BF00042061; CECCARELLI S, 1987, EUPHYTICA, V36, P389, DOI 10.1007-BF00041482; CECCARELLI S, 1994, EUPHYTICA, V77, P205, DOI 10.1007-BF02262633; Chalk PM, 1998, AUST J AGR RES, V49, P303, DOI 10.1071-A97013; Christiansen S, 2011, J AGRON CROP SCI, V197, P146, DOI 10.1111-j.1439-037X.2010.00447.x; Christiansen S, 2000, EXP AGR, V36, P181, DOI 10.1017-S0014479700002015; Christiansen S, 2000, EXP AGR, V36, P195, DOI 10.1017-S0014479700002064; DAY AD, 1975, AGRON J, V67, P430; ERSKINE W, 1993, J AGR SCI, V121, P347; Giorgi F, 2006, GEOPHYS RES LETT, V33, DOI 10.1029-2006GL025734; Giorgi F, 2008, GLOBAL PLANET CHANGE, V63, P90, DOI 10.1016-j.gloplacha.2007.09.005; GUY CL, 1994, PHYSIOLOGY AND DETERMINATION OF CROP YIELD, P417; HADJICHRISTODOULOU A, 1976, J AGR SCI, V87, P489; HADJICHRISTODOULOU A, 1977, EXP AGR, V13, P217, DOI 10.1017-S0014479700007936; HADJICHRISTODOULOU A, 1982, J AGR SCI, V99, P261; ICARDA, 1998, ANN REP 1997 ICARDA; Jones MJ, 2000, J AGR SCI, V135, P223, DOI 10.1017-S0021859699008205; Jones MJ, 1999, J AGRON CROP SCI, V182, P291, DOI 10.1046-j.1439-037x.1999.00297.x; Papastylianou I, 1995, GRASS FORAGE SCI, V50, P456, DOI 10.1111-j.1365-2494.1995.tb02341.x; Papastylianou I., 1999, CHALLENGE PRODUCTION, P11; PASSIOURA JB, 1994, PHYSIOLOGY AND DETERMINATION OF CROP YIELD, P343; Passioura JB, 2010, ADV AGRON, V106, P37, DOI 10.1016-S0065-2113(10)06002-5; PAULSEN GM, 1994, PHYSIOLOGY AND DETERMINATION OF CROP YIELD, P365; Porter JR, 1999, EUR J AGRON, V10, P23, DOI 10.1016-S1161-0301(98)00047-1; PUCKRIDGE DW, 1983, AGR ECOSYST ENVIRON, V9, P229, DOI 10.1016-0167-8809(83)90100-7; Rodriguez D, 2006, AUST J AGR RES, V57, P355, DOI 10.1071-AR04133; Ryan J, 1997, SOILS ICARDAS AGR EX; Ryan J, 2010, J AGR SCI, V148, P205, DOI 10.1017-S0021859609990566; Ryan J, 1998, SOIL TILL RES, V45, P407, DOI 10.1016-S0933-3630(97)00037-8; VANOOSTEROM EJ, 1993, J AGR SCI, V121, P307; WELTZIEN E, 1990, PLANT BREEDING, V104, P58, DOI 10.1111-j.1439-0523.1990.tb00403.x; Wheeler TR, 2000, AGR ECOSYST ENVIRON, V82, P159, DOI 10.1016-S0167-8809(00)00224-3; Yau SK, 2001, COMMUN SOIL SCI PLAN, V32, P379, DOI 10.1081-CSS-100103014; Yau SK, 2003, EUR J AGRON, V19, P599, DOI 10.1016-S1161-0301(03)00006-6; Yau SK, 2003, AGRON J, V95, P821; YAU S K, 1991, Journal of Genetics and Breeding, V45, P71; Yau SK, 2011, AGR WATER MANAGE, V98, P1776, DOI 10.1016-j.agwat.2011.07.0090
Yield and quality of red stigmas from different saffron strains at contrasting Mediterranean sites
No full textThree different saffron strains (Crocus sativus, C. sativus var. 'cashmerianus' and C. cartwrightianus) were tested for two years in field experiments to study their red stigma yield and quality. The experiments were performed at a high-elevation (rainfed or irrigated) site and a coastal site in Lebanon. On average, the two C. sativus strains gave more flowers and stigma yield than C. cartwrightianus. The former was more productive in the more favourable environments, especially at the warmer coastal site, than the latter. C. sativus 'cashmerianus', which yielded better at the coastal site in 2004 and gave a stronger colour strength and aroma, appeared to be the better choice for the area. Mean yield at the coastal site was twice that at the non-irrigated high-elevation site. On average, saffron produced at the coastal site had more colouring strength and bitterness than that produced at the high-elevation site. Nevertheless, viable commercial saffron production may still be possible in the semi-arid, high-elevation Bekaa Valley if irrigation can be provided. © 2006 Cambridge University Press.BASKER D, 1999, SAFFRON CROCUS SAT L, P45; DEMASTRO G, 1993, ACTA HORTIC, V344, P52; GARCIA E, 1997, SCI AM, V275, P24; ISO, 1993, 36321 ISO; ISO, 1993, 36322 ISO; MATHEW B, 1999, SAFFRON CROCUS SAT L, P17; McGimpsey JA, 1997, NEW ZEAL J CROP HORT, V25, P159; MCINTOSH MS, 1983, AGRON J, V75, P153; Molina R, 2004, SCI HORTIC-AMSTERDAM, V103, P79, DOI 10.1016-j.scienta.2004.04.008; Molina R, 2005, SCI HORTIC-AMSTERDAM, V103, P361, DOI 10.1016-j.scienta.2004.06.005; MOLLAFILABI A, 2003, P 3 NAT S SAFF MASH; Negbi M., 1999, SAFFRON CROCUS SATIV, P1; Pardo JE, 2002, ITAL J FOOD SCI, V14, P413; RYAN J, 1980, PUBLICATION BEIRUT A, V64; YAU SK, 2004, LEBANESE SCI J, V5, P13; Zohary D, 1988, DOMESTICATION PLANTS22
Does Growing Safflower before Barley Reduce Barley Yields under Mediterranean Conditions?
No full textSafflower (Carthamus tinctorius L.) which has deep roots can be grown as an economical oil crop in semiarid rain-fed areas of West Asia and North Africa where barley (Hordeum vulgare L.) monoculture is a common practice. In this study we sought to: (i) evaluate the effect of safflower on the yield of the following barley crop and (ii) compare such effect with other crops to determine the potential of rotating safflower with barley. Two series of experiments were conducted under rain-fed conditions in Lebanon's Bekaa Valley (2002-2003 to 2003-2004 and 2005-2006 to 2010-2011). In Series 1 there were 12 2-yr rotation systems whereas in Series 2 3 rotation systems were studied. Results from the two and three rotation cycles were reported from the first and second series of experiments respectively. Rotation effects were significant (P ≤ 0.05) for barley grain yield straw yield and harvest index but rotation × year interaction was not significant. In Series 1 barley after safflower gave the highest harvest index (0.40 kg kg-1) and mean grain yield (1400 kg ha-1) that is 28 to 72percent higher grain yield than after the other crops except after cumin (Cuminum cyminum L.) and common vetch (Vicia sativa L.) for grazing. In Series 2 grain yield and harvest index of barley aft er safflower (4090 kg ha-1 0.36 kg kg-1) were higher than that after barley (3010 kg ha-1 0.32 kg kg-1). Thus growing safflower before barley increased rather than decreased barley yields and was comparable to or better than after some legumes. Barley-safflower therefore appears to be a viable rotation in semiarid rain-fed Mediterranean areas. © 2012 by the American Society of Agronomy.Aase JK, 2000, AGR WATER MANAGE, V43, P345, DOI 10.1016-S0378-3774(99)00062-1; Baltensperger D. D., 2002, Trends in new crops and new uses. Proceedings of the Fifth National Symposium, Atlanta, Georgia, USA, 10-13 November, 2001, P183; Chalk PM, 1998, AUST J AGR RES, V49, P303, DOI 10.1071-A97013; Cook RJ, 2002, CAN J PLANT PATHOL, V24, P349; EHLERS W, 1983, SOIL TILL RES, V3, P261, DOI 10.1016-0167-1987(83)90027-2; FAO, 1998, CROP EV GUID COMP CR, V56; Genstat 5 Committee, 1993, GENST 5 REF MAN; Hamadeh SK, 1996, SMALL RUMINANT RES, V21, P173, DOI 10.1016-0921-4488(95)00831-4; Jones MJ, 2000, J AGR SCI, V135, P237, DOI 10.1017-S0021859699008199; Jones MJ, 2000, J AGR SCI, V135, P251, DOI 10.1017-S0021859699008187; Jones MJ, 1999, J AGRON CROP SCI, V182, P291, DOI 10.1046-j.1439-037x.1999.00297.x; Kirkegaard J, 2008, FIELD CROP RES, V107, P185, DOI 10.1016-j.fcr.2008.02.010; Krupinsky JM, 2004, AGRON J, V96, P259; Krupinsky JM, 2006, AGR SYST, V88, P227, DOI 10.1016-j.agsy.2005.03.011; McKenzie BM, 2009, FIELD CROP RES, V112, P165, DOI 10.1016-j.fcr.2009.02.012; Merrill SD, 2002, SOIL SCI SOC AM J, V66, P913; Miller PR, 2002, CAN J PLANT SCI, V82, P307; Pala M., 1997, P 4 INT SAFFL C BAR, P86; Passioura JB, 2010, ADV AGRON, V106, P37, DOI 10.1016-S0065-2113(10)06002-5; Stevenson FC, 1996, CAN J PLANT SCI, V76, P735; Suleimenov M.K., 2004, AGR CENTRAL ASIA RES, P188; Tanaka DL, 2005, AGRON J, V97, P385; Tonks D., 2004, IMPACT ALTERNATIVE C; Yau SK, 2003, EUR J AGRON, V19, P599, DOI 10.1016-S1161-0301(03)00006-6; Yau SK, 2004, EXP AGR, V40, P453, DOI 10.1017-S0014479704002121; Yau S.K., 2004, CSSA SPEC PUBL, V32, P219; Yau SK, 2010, AGRON J, V102, P269, DOI 10.2134-agronj2009.0242; Yau S.K., 1999, SESAME SAFFLOWER NEW, V14, P970
Conservation versus Conventional Tillage on Performance of Three Different Crops
No full textConservation tillage, besides being more economical, prevents soil erosion and has other beneficial effects on our environment, but few studies have been conducted on differential responses of different crops to conservation tillage. The main objective of this study was to examine the interaction of tillage with crop species. Rainfed field experiments in a strip-plot design with four replicates were conducted in the semiarid, central Bekaa Valley of Lebanon for 2 yr. There were three tillage treatments: conventional (CT), minimum (MT), and no tillage (NT). Crops studied were barley (Hordeum vulgare L.), chickpea (Cicer arietinum L.), and safflower (Carthamus tinctorius L.). The experiment was initiated in 2005-2006 on a field in which CT was practiced for years. In 2006-2007, the experiment was conducted on the exact site following the same 2005-2006 randomization. In each year, NT had similar weed density and dry weight m-2 as CT, and mean weed infestation over years was lower in CT and NT than in MT. Year × tillage × crop interaction was significant for plant height in April, days to flowering-heading, seed yield, and harvest index. Tillage × crop interaction existed for seed and straw yields, harvest index, and plant height at maturity. Barley yielded poorer in NT than in CT, but similar yields were obtained in NT and CT for chickpea and safflower, suggesting that the tap root system of chickpea and safflower may be more adapted to NT than the fibrous root system of barley. Results of this study could be used to organize demonstration trials to help encouraging farmers to try practicing NT. © 2010 by the American Society of Agronomy.Alvarez R, 2009, SOIL TILL RES, V104, P1, DOI 10.1016-j.still.2009.02.005; Angas P, 2006, SOIL TILL RES, V87, P59, DOI 10.1016-j.still.2005.02.036; BEUKES DJ, 2004, CHALLENGES STRATEGIE, P291; Blackshaw RE, 2007, AGRON J, V99, P122, DOI 10.2134-agronj2006.0202; Cantero-Martinez C, 2003, FIELD CROP RES, V84, P341, DOI 10.1016-S0378-4290(03)00101-1; De Vita P, 2007, SOIL TILL RES, V92, P69, DOI 10.1016-j.still.2006.01.012; DOSTER DH, 1983, J SOIL WATER CONSERV, V38, P504; Duiker SW, 2006, AGRON J, V98, P436, DOI 10.2134-agronj2005.0063; Fernandez RO, 2007, SOIL TILL RES, V94, P47, DOI 10.1016-j.still.2006.07.003; Ferreras LA, 2000, SOIL TILL RES, V54, P31, DOI 10.1016-S0167-1987(99)00102-6; GODWIN RJ, 1990, AGR ENG DEV TILLAGE; Halvorson AD, 2002, AGRON J, V94, P1429; Halvorson AD, 2006, AGRON J, V98, P63, DOI 10.2134-agronj2005.0174; Hawtin G. C., 1980, Advances in legume science (Summerfield, R.J.; Bunting, A.H. [Editors])., P613; Holland JM, 2004, AGR ECOSYST ENVIRON, V103, P1, DOI 10.1016-j.agee.2003.12.018; *ICARDA, 2007, ICARDA ANN REP 2006; JOHNSON RR, 1994, J PROD AGRIC, V7, P43; Knowles P. F., 1976, Evolution of crop plants., P31; Lal R, 2007, SOIL TILL RES, V94, P1, DOI 10.1016-j.still.2007.02.002; LARNEY FJ, 2004, CHALLENGES STRATEGIE, P113; Latta J, 2003, FIELD CROP RES, V83, P173, DOI 10.1016-S0378-4290(03)00073-X; Lithourgidis AS, 2006, CROP SCI, V46, P1187, DOI 10.2135-cropsci2005.09-0321; Lopez-Bellido RJ, 2002, AUST J AGR RES, V53, P1027, DOI 10.1071-AR01142; Lopez-Bellido RJ, 2003, AGRON J, V95, P1253; Mazzoncini M, 2008, AGRON J, V100, P1418, DOI 10.2134-agronj2007.0173; Mrabet R., 2008, SPECIAL PUBLICATION, V3, P393; MUNOZROMERO V, 2009, PLANT SOIL IN PRESS; Omonode RA, 2006, SOIL SCI SOC AM J, V70, P419, DOI 10.2136-sssaj2005.0083; Pala M., 2007, P INT WORKSH CONS AG, P165; Tarkalson DD, 2006, AGRON J, V98, P26, DOI 10.2134-argonj2004.0240; Temperly RJ, 2006, AGRON J, V98, P999, DOI 10.2134-agronj2005.0215; *USDA, 2002, SOIL QUAL AGR TECHN, V15; Ussiri DAN, 2009, SOIL TILL RES, V104, P247, DOI 10.1016-j.still.2009.03.001; Wan CG, 2000, PLANT SOIL, V219, P117, DOI 10.1023-A:1004740511326; Weiss EA, 1983, OIL SEED CROPS; Yau SK, 2004, EXP AGR, V40, P453, DOI 10.1017-S0014479704002121; Yau SK, 2008, AGRON J, V100, P1430, DOI 10.2134-agronj2007.0223; YAU SK, 2005, P 6 INT SAFFL C IST, P92; Yau SK, 2005, AUST J AGR RES, V56, P1227, DOI 10.1071-AR05074; Yau SK, 2003, AGRON J, V95, P82146
Turbulent drag reduction by hydrophobic surfaces with shear-dependent slip length
No full textThe stabilisation of a parabolic equilibrium profile in a three-dimensional (3D) turbulent channel flow for an incompressible fluid is addressed with the objective of achieving drag reduction. The formulation of this problem stems from Balogh’s work [1] where Lyapunov stability analysis was used to devise prototype feedback laws and prove global stability of the solutions. This treatment only considers the controller as a mathematical artefact, but it can actually be linked to physical control strategies modelling hydrophobic surfaces and porous media. In the former, only linear slip velocity boundary conditions (BC) were considered [8]. However, experiments [2] have suggested that the slip length may be shear-dependent. Motivated by these, the effect on drag reduction of a shear-dependent slip length surface is examined in the present study using Direct Numerical Simulations (DNS) at Re τ0 = u τ0 δ/ν ≃ 180. δ is the channel half height, u τ0 the wall-shear velocity for regular no-slip walls channel and ν the kinematic viscosity. The theoretical analysis in [5], is extended to this new model. The proposed formulation shows that the skin-friction coefficient can be reduced by tuning the parameters in the shear-dependent slip length model. The results, which verified by DNS simulations, show that by taking a slip length value based on a constant slip model [8] and combining it within a shear-dependent model, up to 50% drag reduction can be obtained. The effect of control is further assessed by formulating the Fukagata identity [4] with general boundaries; the weighted Reynolds shear-stress for each quadrant shows an enhanced reduction in the sweep/ejection events compared to the constant slip model
Hydrodynamical turbulence by fractal fourier decimation
No full textWe present a systematic numerical investigation of high-resolution 3D isotropic and homogeneous turbulence resolved on a decimated set of Fourier modes. Fractal decimation acts to decrease the effective dimensionality of the flow by allowing triadic interactions only in a set of Fourier modes N(k) proportional to k^DF for large k. While keeping the symmetries of the original 3D Navier-Stokes equations unchanged, a dramatic change in small-scale statistics is detected at decreasing the fractal dimension DF . Already at fractal dimension DF = 2.8, a global self-similar behaviour is observed in the inertial range of scales, the consequence of such transition are the restoration of the scaling symmetry and vorticity distribution that becomes close to Gaussian. We relate the results to the different roles of local vs non-local interactions in the energy transfer range
Least Squares Fitting of Chacón-Gielis Curves by the Particle Swarm Method of Optimization
No full textRicardo Chacón generalized Johan Gielis's superformula by introducing elliptic functions in place of trigonometric functions. In this paper an attempt has been made to fit the Chacón-Gielis curves (modified by various functions) to simulated data by the least squares principle. Estimation has been done by the Particle Swarm (PS) methods of global optimization. The Repulsive Particle Swarm optimization algorithm has been used. It has been found that although the curve-fitting exercise may be satisfactory, a lack of uniqueness of Chacón-Gielis parameters to data (from which they are estimated) poses an insurmountable difficulty to interpretation of findings.Least squares multimodal nonlinear curve-fitting; Ricardo Chacón; Jacobian Elliptic functions; Weierstrass ; Gielis super-formula; supershapes; Particle Swarm method; Repulsive Particle Swarm method of Global optimization; nonlinear programming; multiple sub-optima; global; local optima; fit; empirical; estimation; cellular automata; fractals
Boron deficiency in rainfed wheat in pakistan: Incidence, spatial variability and management strategies
No full textBoron (B) deficiency is potentially an important nutrient constraint in calcareous soils. We determined B deficiency incidence and spatial distribution in rainfed wheat (Triticum aestivum L.) in 1.82 Mha Pothohar plateau in Pakistan, its relationship with soil types, crop responses to B, and internal B requirement and B fertilizer use efficiency of wheat. Plant and soil analyses indicated deficiency in 64percent of the 61 sampled fields; geostatistics-aided contour maps delineated B deficient areas. In rainfed field experiments, B use increased wheat yields up to 11percent. Fertilizer requirement was 1.2 kg B ha-1; critical B concentration (mg kg-1) ranges were: young whole shoots, 4-6; flag leaves, 5-7. Boron uptake by wheat was 0.14-0.58percent of applied dosage, leaving substantial residual impact. Highly cost-effective B use or B-efficient genotype adoption can enhance wheat productivity and grower-income. Such effective nutrient assessment and management approaches can be beneficially adopted elsewhere as well. © Taylor and Francis Group, LLC.Alloway B. J., 2008, MICRONUTRIENT DEFICI; Berger KC, 1944, SOIL SCI, V57, P25, DOI 10.1097-00010694-194401000-00003; Bergmann W, 1992, NUTR DISORDERS PLANT; BHATTI AU, 1991, REMOTE SENS ENVIRON, V37, P181, DOI 10.1016-0034-4257(91)90080-P; Bingham F. T., 1982, Methods of soil analysis. Part 2. Chemical and microbiological properties, P431; GAINES TP, 1979, COMMUN SOIL SCI PLAN, V10, P1099, DOI 10.1080-00103627909366965; Goldberg S., 1993, Boron and its role in crop production., P3; Gupta U. C., 1993, BORON ITS ROLE CROP; Havlin J.L., 2005, SOIL FERTILITY FERTI; HOLLOWAY RE, 1992, AUST J AGR RES, V43, P987, DOI 10.1071-AR9920987; Jones J R, 1991, PLANT ANAL HDB; Keren R., 1985, ADV SOIL SCI, V1, P229; Li B, 1978, J NE AGR COLL, V3, P1; Munson R. D., 1990, Soil testing and plant analysis., P359; Rashid A, 2008, MICRONUTRIENT DEFICI, P149, DOI 10.1007-978-1-4020-6860-7_6; Rashid A, 1997, COMMUN SOIL SCI PLAN, V28, P441, DOI 10.1080-00103629709369802; Rashid A., 2006, P IFA INT WORKSH MIC; Rashid A, 1997, COMMUN SOIL SCI PLAN, V28, P149, DOI 10.1080-00103629709369779; RERKASEM B, 1994, AGRON J, V86, P887; Rerkasem B, 1997, EUPHYTICA, V96, P257, DOI 10.1023-A:1003093532561; Rerkasem B, 2004, FIELD CROP RES, V89, P173, DOI 10.1016-j.fcr.2004.01.022; Reuter DJ, 1997, PLANT ANAL INTERPRET, P81; Reuter J., 1997, PLANT ANAL INTERPRET, P3; Shorrocks VM, 1997, PLANT SOIL, V193, P121, DOI 10.1023-A:1004216126069; Shorrocks V.M., 1992, P INT S ROL SULPH MA, P39; Soylu S, 2004, J PLANT NUTR, V27, P1077, DOI 10.1081-PLN-120037537; Subedi KD, 1997, EUPHYTICA, V95, P21, DOI 10.1023-A:1002926117203; TIWARI R J, 1988, Journal of the Indian Society of Soil Science, V36, P180; WEBB RA, 1972, J HORTIC SCI BIOTECH, V47, P309; WEIR RG, 1983, 1183 NEW S WAL DEP A; Yau SK, 2008, CROP SCI, V48, P854, DOI 10.2135-cropsci2007.10.053923
- …
