Sawan, Z.M., Hafez, S.A., Basyony, A.E. and Alkassas, A.R. (2007) Cottonseed: Protein, oil yields, and oil properties as influenced by potassium fertilization and foliar application of zinc and phosphorus. Grasas Y. Aceites, 58, 40-48.
 Reddy, A.R., Reddy, K.R., Padjung, R. and Hodges, H.F. (1996) Nitrogen nutrition and photosynthesis in leaves of Pima cotton. Journal of Plant Nutrition, 19, 755-770. http://dx.doi.org/10.1080/01904169609365158
 Rinehardt, J.M., Edmisten, K.L., Wells, R. and Faircloth, J.C. (2004) Response of ultra-narrow and conventional spaced cotton to variable nitrogen rates. Journal of Plant Nutrition, 27, 743-755. http://dx.doi.org/10.1081/PLN-120030379
 Ansari, M.S. and Mahey, R.K. (2003) Growth and yield of cotton species as affected by sowing dates and nitrogen levels. Punjab Agricultural University, Journal of Research, 40, 8-11.
 Patil, B.N., Lakkineni, K.C. and Bhargava, S.C. (1996) Seed yield and yield contributing characters as influenced by N supply in rapeseed-mustared. Journal of Agronomy and Crop Science, 177, 197-205. http://dx.doi.org/10.1111/j.1439-037X.1996.tb00237.x
 Frink, C.R., Waggoner, P.E. and Ausubel, J.H. (1999) Nitrogen fertilizer: Retrospect and prospect. Proceedings of the National Academy of Sciences of the United States of America, 96, 1175-1180. http://dx.doi.org/10.1073/pnas.96.4.1175
 Kheir, N.F., Harb, E.Z., Moursi, H.A. and El-Gayar, S.H. (1991) Effect of salinity and fertilization on flax plants (Linum usitatissimum L.). II. Chemical composition. Bulletin of Faculty of Agriculture-University of Cairo, 42, 57-70.
 Taiz, L. and Zeiger, E. (1991) Plant physiology: Mineral nutrition. The Benjamin Cummings Publishing Co., Inc. Redwood City, 100-119.
 Rodriguez, D., Zubillaga, M.M., Ploschuck, E., Keltjens, W., Goudriaan, J. and Lavado, R. (1998) Leaf area expansion and assimilate prediction in sunflower growing under low phosphorus conditions. Plant and Soil, 202, 133-147. http://dx.doi.org/10.1023/A:1004348702697
 Sasthri, G., Thiagarajan, C.P., Srimathi, P., Malarkodi, K. and Venkatasalam, E.P. (2001) Foliar application of nutrient on the seed yield and quality characters of nonaged and aged seeds of cotton cv. MCU5. Madras Agricultural Journal, 87, 202-206.
 Stewart, W.M., Reiter, J.S. and Krieg, D.R. (2005) Cotton response to multiple application of phosphorus fertilizer. Better Crops with Plant Food, 89, 18-20.
 Singh, V., Pallaghy, C.K. and Singh, D. (2006) Phosphorus nutrition and tolerance of cotton to water stress: I. Seed cotton yield and leaf morphology. Field Crops Research, 96, 191-198. http://dx.doi.org/10.1016/j.fcr.2005.06.009
 Ibrahim, M.E., Bekheta, M.A., El-Moursi, A. and Gaafar, N.A. (2009) Effect of arginine, prohexadione-Ca, some macro and micro-nutrients on growth, yield and fiber quality of cotton plants. World Journal of Agricultural Sciences, 5, 863-870.
 Gebaly Sanaa, G. and El-Gabiery, A.E. (2012) Response of cotton Giza 86 to foliar application of phosphorus and mepiquat chloride under fertile soil condition. Journal of Agricultural Research, 90, 191-205.
 Sangakkara, U.R., Frehner, M. and Nösberger, J. (2000) Effect of soil moisture and potassium fertilizer on shoot water potential, photosynthesis and partitioning of carbon in mungbean and cowpea. Journal of Agronomy and Crop Science, 185, 201-207. http://dx.doi.org/10.1046/j.1439-037x.2000.00422.x
 Colomb, B., Bouniols, A. and Delpech, C. (1995) Effect of various phosphorus availabilities on radiation-use efficiency in sunflower biomass until anthesis. Journal of Plant Nutrition, 18, 1649-1658. http://dx.doi.org/10.1080/01904169509365010
 Gormus, O. (2002) Effects of rate and time of potassium application on cotton yield and quality in Turkey. Journal of Agronomy and Crop Science, 188, 382-388. http://dx.doi.org/10.1046/j.1439-037X.2002.00583.x
 Aneela, S., Muhammad, A. and Akhtar, M.E. (2003) Effect of potash on boll characteristics and seed cotton yield in newly developed highly resistant cotton varieties. Pakistan Journal of Biological Sciences, 6, 813-815.
 Pervez, H., Ashraf, M. and Makhdum, M.I. (2004) Influence of potassium rates and sources on seed cotton yield and yield components of some elite cotton cultivars. Journal of Plant Nutrition, 27, 1295-1317. http://dx.doi.org/10.1081/PLN-120038549
 Pettigrew, W.T., Meredith Jr., W.R. and Young, L.D. (2005) Potassium fertilization effects on cotton lint yield, yield components, and reniform nematode populations. Agronomy Journal, 97, 1245-1251. http://dx.doi.org/10.2134/agronj2004.0321
 Sharma, S.K. and Sundar, S. (2007) Yield, yield attributes and quality of cotton as influenced by foliar application of potassium. Journal of Cotton Research and Development, 21, 51-54.
 Welch, R.M. (1995) Micronutrient nutrition of plants. Critical Reviews in Plant Sciences, 14, 49-82.
 Oosterhuis, D., Hake, K. and Burmester, C. (1991) Leaf feeding insects and mites. Cotton council of America. Cotton Physiology Today, 2, 1-7.
 Rathinavel, K., Dharmalingam, C. and Paneersel vam, S. (2000) Effect of micronutrient on the productivity and quality of cotton seed cv. TCB 209 (Gossypium barbadense L.). Madras Agricultural Journal, 86, 313-316.
 Li, L.L., Ma, Z.B., Wang, W.L. and Tai, G.Q. (2004) Effect of spraying nitrogen and zinc at seedling stage on some physiological characteristics and yield of summer cotton. Journal of Henan Agricultural University, 38, 33-35.
 Rensing, L. and Cornelius, G. (1980) Biological membranes as components of oscillating systems. Biologische Rundschau, 18, 197-209.
 Ma, L.G. and Sun, D.Y. (1997) The involvement of calcium in the light signal transduction chain for phototropism in sunflower seedling. Biologia Plantarum, 39, 569-574.
 Ochiai, E.L. (1977) Bioinorganic chemistry. Allyn & Bacon, Boston, 515 p.
 Zhao, D.L. and Oosterhuis, D.M. (2000) Pix plus and mepiquat chloride effects on physiology, growth, and yield of field-grown cotton. Journal of Plant Growth Regulation, 19, 415-422.
 Wang, Z.L., Yin, Y.P. and Sun, X.Z. (1995) The effect of DPC (N, N-dimethyl piperidinium chloride) on the 14CO2-assimilation and partitioning of 14C assimilates within the cotton plants interplanted in a wheat stand. Photosynthetica, 31, 197-202.
 Kumar, K.A.K., Patil, B.C. and Chetti, M.B. (2004) Effect of plant growth regulators on biophysical, biochemical parameters and yield of hybrid cotton. Karnataka Journal of Agricultural Sciences, 16, 591-594.
 Palomo Gil, A. and Chávez González, J.F. (1997) Response of the early cotton cultivar CIAN 95 to nitrogen fertilizer application. ITEA. Producción Vegetal, 93, 126-132.
 Sarwar Cheema, M., Akhtar, M. and Nasarullah, M. (2009) Effect of foliar application of mepiquat chloride under varying nitrogen levels on seed cotton yield and yield components. Journal of Agricultural Research, 47, 381-388.
 Patil, D.B., Naphade, K.T., Wankhade, S.G., Wanjari, S.S. and Potdukhe, N.R. (1997) Effect of nitrogen and phosphate levels on seed protein and carbohydrate content of cotton cultivars. Indian Journal of Agricultural Research, 31, 133-135.
 Sawan, Z.M., Hafez, S.A. and Basyony, A.E. (2001) Effect of nitrogen and zinc fertilization and plant growth retardants on cottonseed, protein, oil yields, and oil properties. Journal of the American Oil Chemists’ Society, 78, 1087-1092.
 Sawan, Z.M., Hafez, S.A. and Basyony, A.E. (2001) Effect of phosphorus fertilization and foliar application of chelated zinc and calcium on seed, protein and oil yields and oil properties of cotton. Journal of Agricultural Science, 136, 191-198.
 Sawan, Z.M., Hafez, S.A., Basyony, A.E. and Alkassas, A.R. (2007) Nitrogen, potassium and plant growth retardant effects on oil content and quality of cotton seed. Grasas Y. Aceites, 58, 243-251.
 Sawan, Z.M., Fahmy, A.H. and Yousef, S.E. (2009) Direct and residual effects of nitrogen fertilization, foliar application of potassium and plant growth retardant on Egyptian cotton growth, seed yield, seed viability and seedling vigor. Acta Ecologica Sinica, 29, 116-123. http://dx.doi.org/10.1016/j.chnaes.2009.05.008
 Association of Official Analytical Chemists (1985) Official methods of analysis. 14th Edition, Association of Analytical Communities (AOAC), Arlington.
 Kates, M. (1972) Laboratory techniques in biochemistry and molecular biology. In: Work, T.S. and Work, E., Eds., North-Holland Publishing, Amsterdam.
 American Oil Chemists’ Society (1985) Official methods and recommended practices of the american oil chemists’ society. In: Walker, R.O., Ed., 3rd Edition, American Oil Chemists’ Society, Champaign.
 Vogel, A.I. (1975) A textbook of practical organic chemistry. 3rd Edition, English Language Book Society and Longman Group, Harlow.
 Ashoub, A.H., Basyony, A.E. and Ebad, F.A. (1989) Effect of plant population and nitrogen levels on rapeseed oil quality and quantity. Annals of Agricultural Science, Moshtohor, 27, 761-770.
 Snedecor, G.W. and Cochran, W.G. (1980) Statistical methods. 7th Edition, Iowa State University Press, Ames.
 Abdel-Malak, K.I., Radwan, F.E. and Baslious, S.I. (1997) Effect of row width, hill spacing and nitrogen levels on seed cotton yield of Giza 83 cotton cultivar. Egyptian Journal of Agricultural Research, 75, 743-752.
 Saleem, M.F., Shakeel, A., Bilal, M.F., Shahid, M.Q. and Anjum, S.A. (2010) Effect of different phosphorus levels on earliness and yield of cotton cultivars. Soil & Environment, 29, 128-135.
 Hamed, F.S., Abo El-Hamd, A.S., Ibrahim, M.M. and El-Sayed, A.E.M. (2012) Effect of some cultural practices on growth, flowering, earliness characters and yield of cotton plant variety Giza 90 (Gossypium barbadense L.). Egyptian Journal of Agricultural Research, 90, 1649-1673.
 Gardner, F.P. (1988) Growth and partitioning in peanut as influenced by gibberellic acid and daminozide. Agronomy Journal, 80, 159-163. http://dx.doi.org/10.2134/agronj1988.00021962008000020004x
 Nepomuceno, A.L., Oosterhuis, D.M. and Steger, A. (1997) Duration of activity of the plant growth regulators PGR-IV and mepiquat chloride. Special Reports-Agricultural Experiment Station, Division of Agriculture, University of Arkansas, Arkansas, No. 183, 136-139.
 Abdel-Al, M.H. (1998) Response of Giza 85 cotton cultivar to the growth regulators Pix and Atonic. Egyptian Journal of Agricultural Research, 76, 1173-1181.
 Pípolo, A.E., Athayde, M.L.F., Pípolo, V.C. and Parducci, S. (1993) Comparison of different rates of chlorocholine chloride applied to herbaceous cotton. Pesquisa Agropecuária Brasileira, 28, 915-923.
 Sawan, Z.M., Basyony, A.E., McCuistion, W.L. and El-Farra, A.A. (1993) Effect of plant population densities and application of growth retardants on cottonseed yield and quality. Journal of the American Oil Chemists’ Society, 70, 313-317.
 Zeng, Q.F. (1996) Researchers on the effect of zinc applied to calcareous soil in cotton field. China Cottons, 23, 21.
 Carvalho, L.H., Chiavegato, E.J., Cia, E., Kndo, J.I., Sabino, J.C., Pettinelli Junior, A., Bortoletto, N. and Gallo, P.B. (1994) Plant growth regulators and pruning in the cotton crop. Bragantia, 53, 247-254. http://dx.doi.org/10.1590/S0006-87051994000200014
 Pandrangi, R.B., Wankhade, S.G. and Kedar, G.S. (1992) Response of cotton (Gossypium hirsutum L.) to N and P grown under rainfed conditions. Crop Research, 5, 54-58.
 Sawan, Z.M., Sakr, R.A., Ahmed, F.A. and Abd-Al-Samad, A.M. (1991) Effect of 1,1-dimethyl piperidinium chloride (Pix) on the seed, protein, oil and fatty acids of Egyptian cotton. Journal of Agronomy and Crop Science, 166, 157-161. http://dx.doi.org/10.1111/j.1439-037X.1991.tb00899.x
 Sawan, Z.M., El-Farra, A.A. and Mohamed, Z.A. (1988) Effect of nitrogen fertilization, foliar application of calcium and some micro-elements on cottonseed, protein and oil yields and oil properties of Egyptian cotton. Annali di Botanica, 46, 167-174.
 Prabhuraj, D.K., Badiger, M.K. and Manure, G.R. (1993) Growth and yield of sunflower (Helianthus annuus) as influenced by levels of phosphorus, sulphur and zinc. Indian Journal of Agronomy, 38, 427-430.
 Bybordi, A. and Mamedov, G. (2010) Evaluation of application methods efficiency of zinc and iron for canola (Brassica napus L.). Notula Scientia Biologicae, 2, 94103.
 Sugiyama, T., Mizuno, M. and Hayashi, M. (1984) Partitioning of nitrogen among Ribulose-1, 5-bisphosphate carboxylase/oxygenase, phosphoenolpyruvat carboxylase, and pyruvate orthophosphate dikinase as related to biomass productivity in maize seedlings. Plant Physiology, 75, 665-669. http://dx.doi.org/10.1104/pp.75.3.665
 Hedin, P.A., McCarthy, J.C. and Jenkins, J.N. (1988) Effect of CCC and PIX related bioregulators on gossypol, protein, yield and seed properties of cotton. Journal of the Mississippi Academy of Sciences, 33, 49-57.
 Kar, C., Barua, B. and Gupta, K. (1989) Response of the safflower plant (Carthamus tinctorius L. cv. JLA 900) towards plant growth retardants dikegulac sodium, CCC and SADH. Indian Journal of Plant Physiology, 23, 144-147.
 Wang, H.Y. and Chen, Y. (1984) A study with 32P on the effect of growth regulators on the distribution of nutrients with cotton plants. China Cottons, 4, 29-30.
 Kler, D.S., Raj, D. and Dhillon, G.S. (1991) Chemical regulated growth, development and light penetration in American cotton (Gossypium hirsutum L.). Environment and Ecology, 9, 584-588.
 Osman, R.O. and Abu-Lila, B.H. (1985) Studies on the effect of gibberellic acid and Cycocel on flax plants (Linum usitatissimum L.), seed oil content and oil composition. Zeitschrift fur Acker-und Pflanzenbau, 155, 82-88.
 Guinn, G. (1984) Boll abscission in cotton. In: Gupta, U.S., Ed., Crop Physiology: Advancing Frontiers, Mohan Primlani for Oxford & IBH Publishing Co., New Delhi, 177-225.
 Saleem, M.F., Shakeel, A., Bilal, M.F., Shahid, M.Q. and Anjum, S.A. (2010) Effect of different phosphorus levels on earliness and yield of cotton cultivars. Soil & Environment, 29, 128-135.
 Glass, A.D.M. (1989) Plant nutrition. An introduction to current concepts. Jones and Bartlett Publishers, Boston/ Portola Valley.
 Shui, J.G. and Meng, S.F. (1990) Effects of lime application on cotton yield in red soil fields. China Cottons, 1, 26-29.
 Wright, S.D., Munk, D., Munier, D., Vargas, R., Weir, B., Roberts, B. and Jimenez Jr., M. (1995) Effect of aminofol/ boll-set plus calcium zinc on California cotton. Proceedings Beltwide Cotton Conferences, San Antonio, TX, USA, 4-7 January 1995, Volume 2, National Cotton Council, Memphis.
 Kosheleva, L.L., Bakhnova, K.V., Semenova, T.A. and Mil’Kevich, Z.A. (1984) Effect of phosphorus nutrition on metabolism of young fiber flax plants in relation to assimilate distribution in them. Referativnyi Zhurnal, 6, 533.
 El-Debaby, A.S., Hammam, G.Y. and Nagib, M.A. (1995) Effect of planting date, N and P application levels on seed index, lint percentage and technological characters of Giza 80 cotton cultivar. Annals of Agricultural Science, Moshtohor, 33, 455-464.
 Bora, P.C. (1997) Effect of gypsum and lime on performance of Brassica varieties under rainfed condition. Indian Journal of Agronomy, 42, 155-158.
 Davidson, F.M. and Long, C.M. (1958) The structure of the naturally occurring phosphoglycerides. 4. Action of cabbage leaf phospholipase. Biochemical Journal, 69, 458.
 Shchitaeva, V.A. (1984) Effect of zinc on metabolic activity of the root system of fine-fibered cotton. Izvestiya Akademii Nauk Turkmenskoi SSR, Biologicheskaya, 4, 8-13.
 Gushevilov, Zh. and Palaveeva, Ts. (1991) Effect of longterm systematic fertilizer application on sunflower yield and quality. Pochvoznanie i Agrokhimiya, 26, 20-26.
 Gebaly Sanaa, G. (2012) Physiological effects of potassium forms and methods of application on cotton variety Giza 80. Egyptian Journal of Agricultural Research, 90, 1633-1646.
 Russell, E.W. (1973) Soil condition and plant growth. The English Language Book Society and Longman, London, 448 p.
 Ghourab, M.H.H., Wassel, O.M.M. and Raya, N.A.A. (2000) Response of cotton plants to foliar application of (Pottasin-P)TM
under two levels of nitrogen fertilizer. Egyptian Journal of Agricultural Research, 78, 781-793.
 Wiatrak, P.J., Wright, D.L. and Marois, J.J. (2006) Development and yields of cotton under two tillage systems and nitrogen application following white lupine grain crop. Journal of Cotton Science, 10, 1-8.
 Cakmak, I. (2000) Possible roles of zinc in protecting plant cells from damage by reactive oxygen species. New Phytologist, 146, 185-205. http://dx.doi.org/10.1046/j.1469-8137.2000.00630.x
 Bednarz, C.W. and Oosterhuis, D.M. (1999) Physiological changes associated with potassium deficiency in cotton. Journal of Plant Nutrition, 22, 303-313. http://dx.doi.org/10.1080/01904169909365628
 Marschner, H. (1995) Mineral nutrition of higher plants. 2nd Edition, Academic Press, London.
 Mekki, B.B., El-Kholy, M.A. and Mohamed, E.M. (1999) Yield, oil and fatty acids content as affected by water deficit and potassium fertilization in two sunflower cultivars. Egyptian Journal of Agronomy, 21, 67-85.
 Froment, M.A., Turley, D. and Collings, L.V. (2000) Effect of nutrition on growth and oil quality in linseed. Tests of Agrochemicals and Cultivars, 21, 29-30.
 Klug, A. and Rhodes, D. (1987) “Zinc fingers”: A novel protein motif for nucleic acid recognition. Trends in Biochemical Sciences, 12, 464-469. http://dx.doi.org/10.1016/0968-0004(87)90231-3
 Romheld, V. and Marschner, H. (1991) Micronutrients in agriculture. 2nd Edition, Soil Science Society of America Book Series, no 4, Soil Science Society of America, Inc., Madison, Wisconsin, 297-328.
 Khan, N.A., Ansari, H.R. and Samiullah (1997) Effect of gibberellic acid spray and Basal nitrogen and phosphorus on productivity and fatty acid composition of rapeseedmustard. Journal of Agronomy and Crop Science, 179, 29-33. http://dx.doi.org/10.1111/j.1439-037X.1997.tb01144.x
 Legé, K.E., Cothren, J.T. and Morgan, P.W. (1997) Nitrogen fertility and leaf age effects on ethylene production of cotton in a controlled environment. Plant Growth Regulation, 22, 23-28.
 McConnell, J.S. and Mozaffari, M. (2004) Yield, petiole nitrate, and node development responses of cotton to early season nitrogen fertilization. Journal of Plant Nutrition, 27, 1183-1197. http://dx.doi.org/10.1081/PLN-120038543
 Pettigrew, W.T. (1999) Potassium deficiency increases specific leaf weights of leaf glucose levels in field-grown cotton. Agronomy Journal, 91, 962-968. http://dx.doi.org/10.2134/agronj1999.916962x
 Cakmak, I., Hengeler, C. and Marschner, H. (1994) Partitioning of shoot and root dry matter and carbohydrates in bean plants suffering from phosphorus, potassium and magnesium deficiency. Journal of Experimental Botany, 45, 1245-1250. http://dx.doi.org/10.1093/jxb/45.9.1245
 Mullins, G.L., Schwab, G.J. and Burmester, C.H. (1999) Cotton response to surface applications of potassium fertilizer: A 10-year summary. Journal of Production Agriculture, 12, 434-440. http://dx.doi.org/10.2134/jpa1999.0434
 Prakash, R., Prasad, M. and Pachauri, D.K. (2001) Effect of nitrogen, chlormequat chloride and FYM on growth yield and quality of cotton (Gossypium hirsutum L.). Annals of Agricultural Research, 22, 107-110.
 Mekki, B.B. (1999) Effect of mepiquat chloride on growth, yield and fiber properties of some Egyptian cotton cultivars. Arab University Journal of Agricultural Science, 7, 455-466.
 Palomo Gil, A., Godoy Avila, S. and Chávez González, J.F. (1999) Reductions in nitrogen fertilizers use with new cotton cultivars: Yield, yield components and fiber quality. Agrociencia, 33, 451-455.
 Ali, S.A. and El-Sayed, A.E. (2001) Effect of sowing dates and nitrogen levels on growth, earliness and yield of Egyptian cotton cultivar Giza 88. Egyptian Journal of Agricultural Research, 79, 221-232.
 Lamas, F.M. (2001) Comparative study of mepiquat chloride and chlormequat chloride application in cotton. Pesquisa Agropecuária Brasileira, 36, 265-272. http://dx.doi.org/10.1590/S0100-204X2001000200008
 Zubillaga, M.M., Aristi, J.P. and Lavado, R.S. (2002) Effect of phosphorus and nitrogen fertilization on sunflower (Helianthus annus L) nitrogen uptake and yield. Journal of Agronomy and Crop Science, 188, 267-274. http://dx.doi.org/10.1046/j.1439-037X.2002.00570.x
 Madraimov, I. (1984) Potassium fertilizers and oil content of cotton seeds. Khlopkovodstvo, 6, 11-12.
 Fan, S.L., Xu, Y.Z. and Zhang, C.J. (1999) Effects of nitrogen, phosphorus and potassium on the development of cotton bolls in summer. Acta Gossypii Sinica, 11, 24-30.
 Stitt, M. (1999) Nitrate regulation of metabolism and growth. Current Opinion in Plant Biology, 2, 178-186. http://dx.doi.org/10.1016/S1369-5266(99)80033-8
 Narang, R.S., Mahal, S.S. and Gill, M.S. (1993) Effect of phosphorus and sulphur on growth and yield of toria (Brassica campestris subsp. oleifera var toria). Indian Journal of Agronomy, 38, 593-597.
 Holmes, M.R.J. and Bennett, D. (1979) Effect of nitrogen fertilizer on the fatty acid composition of oil from low erucic acid rape varieties. Journal of the Science of Food and Agriculture, 30, 264-266. http://dx.doi.org/10.1002/jsfa.2740300309
 Seo, G.S., Jo, J.S. and Choi C.Y. (1986) The effect of fertilization level on the growth and oil quality in sesame (Sesamum indicum L.). Korean Journal of Crop Science, 31, 24-29.
 Salama, A.M. (1987) Yield and oil quality of sunflowers as affected by fertilizers and growth regulators. Növénytermelés, 36, 191-202.
 Mekki, B.B. and El-Kholy, M.A. (1999) Response of yield, oil and fatty acid contents in some oil seed rape varieties to mepiquat chloride. Bulletin of the National Research Center, 24, 287-299.
 Downey, R.K. and Rimmer, S.R. (1993) Agronomic improvement in oil seed Brassicas. Advances in Agronomy, 50, 1-66. http://dx.doi.org/101016/S0065-2113(08)60831-7