Tree-Crop interactions in temperate agroforestry

North American Agroforestry: An Integrated Science and Practice

Volumn , Issue , 2015, Pages 57-74

  Jose, Shibu ^a   Holzmueller, Eric J ^b   Gillespie, Andrew R ^c  

^a UNIVERSITY OF FLORIDA   (United States)

^b SOUTHERN ILLINOIS UNIVERSITY   (United States)

^c PURDUE UNIVERSITY   (United States)

Author keywords

Competitive exclusion principle; Competitive interactions; Complex biophysical interactions; Ecological interactions; Ecological sustainability; Facilitative interactions; Species coexistence; Temperate agroforestry; Tree crop interactions

Indexed keywords

EID: 85103014562     PISSN: None     EISSN: None     Source Type: Book    
DOI: 10.2134/2009.northamericanagroforestry.2ed.c4     Document Type: Chapter

References (122)

1. Allen, S.C., S. Jose, P.K.R. Nair, B.J. Brecke, and C.L. Ramsey. 2004a. Competition for 15N-labled fertilizer in a pecan (Carya illinoensis K. Koch)-cott on (Gossypium hirsutum L.) alley cropping system in the southern United States. Plant Soil 263: 151-164.
2. Allen, S.C., S. Jose, P.K.R. Nair, B.J. Brecke, P. Nkedi-Kizza, and C.L. Ramsey. 2004b. Safety-net role of tree roots: Evidence from a pecan (Carya illinoensis K. Koch)-cott on (Gossypium hirsutum L.) alley cropping system in the southern United States. For. Ecol. Manage. 192: 395-407.
3. Allen, S.C., S. Jose, P.K.R. Nair, B.J. Brecke, V.D. Nair, D.A. Graetz, and C.L. Ramsey. 2005. Nitrogen mineralization in a pecan (Carya illinoensis K. Koch)-cotton (Gossypium hirsutum L.) alley cropping system in the southern United States. Biol. Fertil. Soils 41: 28-37.
4. Alley, J.L., H.E. Garrett, R.L. McGraw, J.P. Dwyer, and C.A. Blanche. 1998. Forage legumes as living mulches for trees in agroforestry practices-preliminary results. Agrofor. Syst. 44: 281-291.
5. Altieri, M.A. 1991. Increasing biodiversity to improve pest management in agro-ecosystems. p. 165-182. In D.L. Hawksworth (ed.) The biodiversity of microorganisms and invertebrates: Its role in sustainable agriculture. CAB International, Wallingford, UK.
6. Bagley, W.T. 1964. Responses of tomatoes and beans to windbreak shelter. J. Soil Water Conserv. 19: 71-73.
7. Baraldi, R., G. Bertazza, J. Bogino, V. Luna, and R. Bott ini. 1995. The effect of light quality on Prunus cerasus II. Changes in hormone levels in plants grown under different light conditions. Photochem. Photobiol. 62: 800-803.
8. Bonilla, C.A., J.F. Muñoz, and M. Vauclin. 1999. Opus simulation of water dynamics and nitrate transport in a field plot. Ecol. Model. 122: 69-80.
9. Boring, L.R., and W.T. Swank. 1984. The role of black locust (Robinia pseudoacacia) in forest succession. J. Ecol. 72: 749-766.
10. Brandle, J.R., L. Hodges, and B. Wight. 2000. Windbreak practices. p. 79-118. In H.E. Garrett, et al. (ed.) North American agroforestry: An integrated science and practice. ASA, Madison, WI.
11. Brandle, J.R., L. Hodges, and X. Zhou. 2004. Windbreaks in sustainable agriculture. Agrofor. Syst. 61: 65-78.
12. Brenner, A.J. 1996. Microclimatic modifications in agroforestry. p. 159-187. In C.K. Ong and P. Huxley (ed.) Tree-crop interactions: A physiological approach. CAB International, Wallingford, UK.
13. Brooker, R.W., and T.V. Callaghan. 1998. The balance between positive and negative plant interactions and its relationship to environmental gradients: A model. Oikos 81: 196-207.
14. Bugg, R.L., M. Sarrantonio, J.D. Dutcher and S.C. Phatak. 1991. Understory cover crops in pecan orchards: possible management systems. Am. J. Alt. Agric. 6: 50-62.
15. Burgess, S.O., M.A. Adams, N.C. Turner, and C.K. Ong. 1998. The redistribution of soil water by tree roots systems. Oecologia 115: 306-311.
16. Burner, D.M. 2003. Influence of alley crop environment on orchardgrass and tall fescue herbage. Agron. J. 95: 1163-1171.
17. Caldwell, M.M., and J.H. Richards. 1989. Hydraulic lift: Water efflux from upper roots improves effectiveness of water uptake by deep roots. Oecologia 79: 1-5.
18. Cannell, M.G.R., M. van Noordwijk, and C.K. Ong. 1996. The central agroforestry hypothesis: The trees must acquire resources that the crop would not otherwise acquire. Agrofor. Syst. 34: 27-31.
19. Casper, B.B., and R.B. Jackson. 1997. Plant competition underground. Annu. Rev. Ecol. Syst. 28: 545-570.
20. Chifflot, V., G. Bertoni, A. Cabanettes, and A. Gavaland. 2006. Beneficial effects of intercropping on the growth and nitrogen status of young wild cherry and hybrid walnut trees. Agrofor. Syst. 66: 13-21.
21. Cleugh, H.A. 2002. Field measurements of windbreak effects on airflow, turbulent exchanges and microclimates. Aust. J. Exp. Agric. 42: 665-677.
22. Corak, S.J., D.G. Blevins, and S.G. Pallardy. 1987. Water transfer in an alfalfa-maize association: Survival of maize during drought. Plant Physiol. 84: 582-586.
23. Davis J.E. and J.M. Norman. 1988. Effects of shelter on plant water use. Agric. Ecosyst. Environ. 22/23: 393-402.
24. Davis, M.H., and S.R. Simmons. 1994a. Tillering response of barley to shifts in light quality caused by neighboring plants. Crop Sci. 34: 1604-1610.
25. Davis, M.H., and S.R. Simmons. 1994b. Far-red light reflected from neighboring vegetation promotes shoot elongation and accelerates flowering in spring barley plants. Plant Cell Environ. 17: 829-836.
26. Dawson, L.A., E.I. Duff, C.D. Campbell, and D.J. Hirst. 2001. Depth distribution of cherry (Prunus avium L.) tree roots as influenced by grass root competition. Plant Soil 231: 11-19.
27. Dawson, T.E. 1993. Hydraulic lift and water use by plants: Implications for water balance, performance and plant- plant interactions. Oecologia 95: 565-574.
28. Delate, K., E. Holzmueller, C. Mize, D. Frederick, and C. Brummer. 2005. Tree establishment and growth using forage ground covers in an alley-cropped system. Agrofor. Syst. 65: 43-52.
29. Douglas, G.B., A.S. Walcroft, S.E. Hurst, J.F. Potter, A.G. Foote, L.E. Fung, W.R.N. Edwards, and C. van den Dijssel. 2006. Interactions between widely spaced young poplars (Populus spp.) and the understory environment. Agrofor. Syst. 67: 177-186.
30. Dupraz, C., V. Simorte, M. Dauzat, G. Bertoni, A. Bernadac, and P. Masson. 1999. Growth and nitrogen status of young walnuts as affected by intercropped legumes in a Mediterranean climate. Agrofor. Syst. 43: 71-80.
31. Espeleta, J.F., J.B. West, and L.A. Donovan. 2004. Speciesspecific patterns of hydraulic lift in co-occurring adult trees and grasses in a sandhill community. Oecologia 138: 341-349.
32. Fisher, R.F. 1978. Juglone inhibits pine growth under certain moisture regimes. Soil Sci. Soc. Am. J. 42: 801-803.
33. Gakis, S., K. Mantzanas, D. Alifragis, V.P. Papanastasis, A. Papaioannou, D. Seilopoulos, and P. Platis. 2004. Effects of understory vegetation on tree establishment and growth in a silvopastoral system in northern Greece. Agrofor. Syst. 60: 149-157.
34. Garcia-Barrios, L., and C.K. Ong. 2004. Ecological interactions, management lessons, and design tools in tropical agroforestry systems. Agrofor. Syst. 61: 221-236.
35. Garrett, H.E., and R.L. McGraw. 2000. Alley cropping practices. p. 149-188. In H.E. Garrett et al. (ed.) North American agroforestry: An integrated science and practice. ASA, Madison, WI.
36. Garrity, D.P. 2004. Agroforestry and the achievement of the millennium development goals. Agrofor. Syst. 61: 5-17.
37. Gause, G.F. 1934. The struggle for existence. Williams & Wilkins, Baltimore, MD.
38. Gillespie, A.R., B.K. Miller, and K.D. Johnson. 1995. Effects of ground cover on tree survival and growth in filter strips of the Cornbelt Region of the midwestern US. Agric. Ecosyst. Environ. 53: 263-270.
39. Gillespie, A.R., S. Jose, D.B. Mengel, W.L. Hoover, P.E. Pope, J.R. Seifert, D.J. Biehle, T. Stall, and T.J. Benjamin. 2000. Defining competition vectors in a temperate alley cropping system in the midwestern USA. 1. Production physiology. Agrofor. Syst. 48: 25-40.
40. Goldberg, D.E. 1990. Components of resource competition in plant communities. p. 27-65. In J.B. Grace and D. Timan (ed.) Perspectives on plant competition. Academic Press, San Diego, CA.
41. Gómez-Gutierrez, J.M., and M. Pérez-Fernández. 1996. The “dehesas”: Silvopastoral systems in semiarid Mediterranean regions with poor soils, seasonal climate, and extensive utilization. p. 55-70. In M. Etienne (ed.) Western European silvopastoral systems. FAO, Rome, Italy.
42. Hardin, G. 1960. The Competitive Exclusion Principle. Science 131: 1292-1297.
43. Holmgren, M., M. Scheffer, and M.A. Huston. 1997. The interplay of facilitation and competition in plant communities. Ecology 78: 1966-1975.
44. Horton, J.L., and S.C. Hart. 1998. Hydraulic lift: A potentially important ecosystem process. Trends Ecol. Evol. 13: 232-235.
45. Hubbell, S.P. 2001. The unified neutral theory of species abundance and diversity. Princeton University Press, Princeton, NJ.
46. Inderjit, S., and A.U. Malik. 2002. Chemical ecology of plants: Allelopathy in aquatic and terrestrial ecosystems. Birkhauser-Verlag, Berlin.
47. Ishikawa, C.M., and C.S. Bledsoe. 2000. Seasonal and diurnal patterns of soil water potential in the rhizosphere of blue oaks: Evidence for hydraulic lift. Oecologia 125: 459-465.
48. Johnson, R. J., and M. M. Beck. 1988. Influences of shelterbelts on wildlife management and biology. Agric., Ecosyst. Environ. 22/23: 301-335.
49. Jose, S. 1997. Interspecific interactions in alleycropping: The physiology and biogeochemistry. Ph.D. Dissertation, Purdue University, West Lafayette, IN, USA.
50. Jose, S. 2002. Black walnut allelopathy: Current state of the science. p. 149-172. In S. Inderjit and A. Mallik (ed.) Chemical ecology of plants: Allelopathy in aquatic and terrestrial ecosystems. Birkhauser-Verlag, Switzerland.
51. Jose, S., and A.R. Gillespie. 1998. Allelopathy in black walnut [Juglans nigra (L.)] alley cropping. I. Spatio-temporal variation in soil juglone in a black walnut-corn [Zea mays (L.)] alley cropping system in the midwestern USA. Plant Soil 203: 191-197.
52. Jose, S., A.R. Gillespie, J.R. Seifert, D.B. Mengel, and P.E. Pope. 2000a. Defining competition vectors in a temperate alley cropping system in the midwestern USA. 3. Competition for nitrogen and litter decomposition dynamics. Agrofor. Syst. 48: 61-77.
53. Jose, S., A.R. Gillespie, J.R. Seifert, and D.J. Biehle. 2000b. Defining competition vectors in a temperate alley cropping system in the midwestern USA. 2. Competition for water. Agrofor. Syst. 48: 41-59.
54. Jose, S., A.R. Gillespie, and S.G. Pallardy. 2004. Interspecific interactions in temperate agroforestry. Agrofor. Syst. 61: 237-255.
55. Jose, S., and E.J. Holzmueller. 2008. Black walnut allelopathy: Implications for intercropping. In A. Mallik (ed.) Advances in allelopathy research. Springer Science, New York.
56. Jose, S., R. Williams, and D. Zamora. 2006. Belowground ecological interactions in mixed-species forest plantations. For. Ecol. Manage. 233: 231-239.
57. Kallenbach, R.L., M.S. Kerley, and G.J. Bishop-Hurley. 2006. Cumulative forage production, forage quality, and livestock performance from an annual ryegrass and cereal rye mixture in a pine-walnut silvopasture. Agrofor. Syst. 66: 43-53.
58. Kelty, M.J. 2000. Species interactions, stand structure, and productivity in agroforestry systems. p. 183-203. In M.S. Ashton and R. Montagnini (ed.) The silvicultural basis for agroforestry systems. CRC Press, New York.
59. Kort, J. 1988. Benefits of windbreaks to field and forage crops. Agric. Ecosyst. Environ. 22/23: 165-191.
60. Kozlowski, T.T., and S.G. Pallardy. 1997. Physiology of woody plants, 2nd ed. Academic Press, San Diego, CA.
61. Krueger, W.C. 1981. How a forest affects a forage crop? Rangelands 3: 70-71.
62. Lambers, H., F.S. Chapin, III, and T.L. Pons. 1998. Plant physiological ecology. Springer-Verlag, New York.
63. Lee, K.H., T.M. Isenhart, and R.C. Schultz. 2003. Sediment and nutrient removal in an established multi-species riparian buffer. J. Soil. Water Conserv. 58: 1-8.
64. Lehmkuhler, J.W., E.E.D. Felton, D.A. Schmidt, K.J. Bader, H.E. Garrett, and M.S. Kerley. 2003. Tree protection methods during the silvopastoral-system establishment in midwestern USA: Cattle performance and tree damage. Agrofor. Syst. 59: 35-42.
65. Lin, C.H., R.L. McGraw, M.F. George, and H.E. Garrett. 1999. Shade effects on forage crops with potential in temperate agroforestry practices. Agrofor. Syst. 44: 109-119.
66. Lin, C.H., R.L. McGraw, M.F. George, and H.E. Garrett. 2001. Nutritive quality and morphological development under partial shade of some forage species with agroforestry potential. Agrofor. Syst. 53: 269-281.
67. Mayer, A.C., V. Stockli, W. Konold, and M. Kreuzer. 2006. Influence of cattle stocking rate on browsing of Norway spruce in subalpine wood pastures. Agrofor. Syst. 66: 143-149.
68. Mcadam, J.H., A.R. Sibbald, Z. Teklehaimanot, and W.R. Eason. 2007. Developing silvopastoral systems and their effects on diversity of fauna. Agrofor. Syst. 70: 81-89.
69. Miller, A.W., and S.G. Pallardy. 2001. Resource competition across the crop-tree interface in a maize-silver maple temperate alley cropping stand in Missouri. Agrofor. Syst. 53: 247-259.
70. Miller, T.E., J.H. Burns, P. Munguia, E.L. Walters, J.M. Kneitel, P.M. Richards, N. Mouquet, and H.L. Buckley. 2005. A critical review of 20 years’ use of the Resource Ratio Theory. Am. Naturalist 165: 439-448. Science 274: 1469-1470.
71. Monteith, J.L., C.K. Ong, and J.E. Corlett. 1991. Microclimate interactions in agroforestry systems. For. Ecol. Manage. 45: 31-44.
72. Moreno, M.G., J.J. Obrador, E. García, E. Cubera, M.J. Montero, F. Pulido, and C. Dupraz. 2007. Driving competitive and facilitative interactions in oak dehesas through management practices. Agrofor. Syst. 70: 25-40.
73. Nair, P.K.R. 1993. An introduction to agroforestry. Kluwer Academic Publishers, Dordrecht, The Netherlands.
74. Nair, P.K.R., R.J. Buresh, D.N. Mugendi, and C.R. Latt. 1999. Nutrient cycling in tropical agroforestry systems: Myths and science. p. 1-31. In L.E. Buck et al. (ed.) Agroforestry in sustainable agricultural systems. CRC Press, Boca Raton, FL.
75. Nair, V.D., P.K.R. Nair, R.S. Kalmbacher, and I.V. Ezenwa. 2007. Reducing nutrient loss from farms through silvopastoral practices in coarse-textured soils of Florida, USA. Ecol. Eng. 29: 192-199.
76. NeSmith, D.S., and J.T. Ritchie. 1992a. Effects of soil water deficits during tassel emergence on development and yield component of maize [Zea mays (L.)]. Field Crops Res. 28: 251-256.
77. NeSmith, D.S., and J.T. Ritchie. 1992b. Short- and long-term responses of corn to preanthesis soil water deficit. Agron. J. 84: 107-113.
78. Ng, H.Y.F., C.F. Drury, V.K. Serem, C.S. Tan, and J.D. Gaynor. 2000. Modeling and testing of the effect of tillage, cropping, and water management practices on nitrate leaching in clay loam soil. Agric. Water Manage. 43: 111-131.
79. Nowak, J., A. Blount, and S. Workman. 2002. Integrated timber, forage, and livestock production-Benefits of silvopasture 1. UF/IFAS Circular 1430. Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL.
80. Ong, C.K., C.R. Black, F.M. Marshall, and J.E. Corlett. 1996. Principles of resource capture and utilization of light and water. p. 73-158. In C.K. Ong and P. Huxley (ed.) Tree-crop interactions: A physiological approach. CAB International, Wallingford, UK.
81. Ong, C.K., J.E. Corlett, R.P. Singh, and C.R. Black. 1991. Above and belowground interactions in agroforestry systems. For. Ecol. Manage. 45: 45-57.
82. Ong, C.K., J.D. Deans, J. Wilson, J. Mutua, A.A.H. Khan, and E.M. Lawson. 1999. Exploring belowground complementarity in agroforestry using sap flow and root fractal techniques. Agrofor. Syst. 44: 87-103.
83. Passarge, J., S. Hol, M. Escher, and J. Huisman. 2006. Competition for nutrients and light: stale coexistence, alternative stable states, or competitive exclusion? Ecol. Monographs 76: 57-72.
84. Penuelas, J., and I. Filella. 2003. Deuterium labeling of roots provides evidence of deep water access and hydraulic lift by Pinus nigra in a Mediterranean forest of NE Spain. Environ. Exp. Bot. 49: 201-208.
85. Powell, G.W., and E.W. Bork. 2006. Aspen canopy removal and root trenching effects on understory vegetation. For. Ecol. Manage. 230: 76-90.
86. Ramsey, C. L., and S. Jose. 2002. Management challenges of pecan and pine based alley cropping systems of the Southern United States. p. 158-163. In W. Schroder and J. Kort (ed.) Temperate agroforestry: Adaptive and mitigative roles. Plains and Prairie Forestry Association, Regina, Canada.
87. Reynolds, P.E., J.A. Simpson, N.V. Thevathasan, and A.M. Gordon. 2007. Effects of tree competition on corn and soybean photosynthesis, growth, and yield in a temperate tree-based agroforestry intercropping system in southern Ontario, Canada. Ecol. Eng. 29: 362-371.
88. Robin, C., M.J.M. Hay, P.C.D. Newton, and D.H. Greer. 1994. Effect of light quality (red: far-red ratio) at the apical bud of the main stolon on morphogenesis of Trifolium repens L. Ann. Bot-London 74: 119-123.
89. Root, R. 1973. Organization of a plant-arthropod association in simple and diverse habitats: the fauna of collards (Brassica oleracea). Ecol. Monographs 43: 95-124.
90. Sanchez, P.A. 2002. Soil fertility and hunger in Africa. Science 295: 2019-2020.
91. Schroth, G. 1999. A review of belowground interactions in agroforestry, focusing on mechanisms and management options. Agrofor. Syst. 43: 5-34.
92. Seifert, J.R. 1991. Agroforestry: The southern Indiana experience of growing oak, walnut, corn, and soybeans. p. 70. In P. Williams (ed.) Agroforestry in North America. Proceedings of the first conference on agroforestry in North America. Ministry of Agriculture and Food, Ontario, Canada.
93. Seiter, S., E.R. Ingham, R.D. William, and D.E. Hibbs. 1995. Increase in soil microbial biomass and transfer of nitrogen from alder to sweet corn in an alley cropping system. p. 56-158. In J.H. Ehrenreich et al. (ed.) Growing a sustainable future. University of Idaho, Boise, ID.
94. Sharifi, M.R., E.T. Nilsen, and P.W. Rundel. 1982. Biomass and net primary productivity of Prosopis glandulosa (Fabaceae) in the Sonoran Desert of California. Am. J. Bot. 69: 760-767.
95. Shainsky, L.J., and S.R. Radosevich. 1992. Mechanisms of competition between Douglas-fir and red alder seedlings. Ecology 73: 30-45.
96. Sharrow, S.H. 1999. Silvopastoralism: Competition and facilitation between trees, livestock, and improved grass- clover pastures on temperate rainfed lands. p. 111-130. In L.E. Buck et al. (ed.) Agroforestry in sustainable agricultural systems. CRC Press, Boca Raton, FL.
97. Silva-Pando, F.J., M.P. Gonzalez-Hernandez, and M.J. Rozados-Lorenzo. 2002. Pasture production in a silvopastoral system in relation with microclimate variables in the Atlantic coast of Spain. Agrofor. Syst. 56: 203-211.
98. Singh, R.P., C.K. Ong, and N. Saharan. 1989. Above- and belowground interactions in alley cropping in semiarid India. Agrofor. Syst. 9: 259-274.
99. Smil, V. 1999. Nitrogen in crop production: An account of global flows. Global Biogeochem. Cycl. 13: 647-662.
100. Smil, V. 2000. Phosphorus in the environment: Natural flows and human interferences. Annu. Rev. Energy Environ. 25: 53-88.
101. Smith, M.W., D.C. Arnold, R.D. Eikenbary, N.R. Rice, A. Shiferaw, B.S. Cheary and B. L. Carroll. 1996. Influence of ground cover on beneficial arthropods in pecan. Biol. Cont. 6: 164-176.
102. Smith, M.W., M.E. Wolf, B.S. Cheary, and B.L. Carroll. 2001. Allelopathy of bermudagrass, tall fescue, redroot pigweed, and cutleaf evening primrose on pecan. HortScience 36: 1047-1048.
103. Söderström, B., B. Svensson, K. Vessby, and A. Glimskär. 2001. Plants, insects and birds in semi-natural pastures in relation to local habitat and landscape factors. Biodiv. Cons. 10: 1839-1863.
104. Stamps, W.T. and M.J. Linit. 1997. Plant diversity and arthropod communities: implications for temperate agroforestry. Agrofor. Syst. 39: 73-89.
105. Thevathasan, N.V., A.M. Gordon, and R.P. Voroney. 1998. Juglone (5-hydroxy-1,4 napthoquinone) and soil nitrogen transformation interactions under a walnut plantation in southern Ontario, Canada. Agrofor. Syst. 44: 151-162.
106. Thevathasan, N.V., and A.M. Gordon. 2004. Ecology of tree intercropping systems in the north temperate region: Experiences from southern Ontario, Canada. Agrofor. Syst. 61: 257-268.
107. Tilman, D. 1980. A graphical-mechanistic approach to competition and predation. Am. Naturalist 116: 362-393.
108. Tilman, D. 1982. Resource competition and community structure. Princeton University Press, Princeton, NJ.
109. Tilman, D. 1990. Constraints and tradeoffs: toward a predictive theory of competition and succession. Oikos, 58, 3-15.
110. Tilman, D., K.G. Cassman, P.A. Matson, R. Naylor, and S. Polasky. 2002. Agricultural sustainability and intensive production practices. Nature 418: 671-677.
111. Todhunter, M.N., and W.F. Beineke. 1979. Effect of fescue on black walnut growth. Tree Planters’ Notes 30: 20-23.
112. Troeh, F.R., and L.M. Thompson. 1993. Soils and soil fertility. 5th ed. Oxford Univ. Press, New York.
113. van Noordwijk, M., G. Lawson, A. Soumaré, J.J.R. Groot, and K. Hairiah. 1996. Root distribution of trees and crops: Competition and/or complementarity. p. 319-364. In C.K. Ong and P. Huxley (ed.) Tree-crop interactions: A physiological approach. CAB International, Wallingford, UK.
114. Vandermeer, J. 1989. The ecology of intercropping. Cambridge Univ. Press, Cambridge, UK.
115. Von Kiparski, G.R., L.S. Lee, and A.R. Gillespie. 2007. Occurrence and fate of the phytotoxin juglone in alley soils under black walnut trees. J. Environ. Qual. 36: 709-717.
116. Waring, H.D., and P. Snowdon. 1985. Clover and urea as sources of nitrogen for the establishment of Pinus radiata. Aust. Forest Res. 15: 115-121.
117. Wanvestraut, R., S. Jose, P.K.R. Nair, and B.J. Brecke. 2004. Competition for water in a pecan-cotton alley cropping system. Agrofor. Syst. 60: 167-179.
118. Williams-Guillén, K., I. Perfecto, and J. Vandermeer. 2008. Bats limit insects in a neotropical agroforestry system. Science 320: 70.
119. Wojtkowski, P. 1998. The theory and practice of agroforestry design. Science Publishers, Enfield, NH.
120. Yunusa, I.A.M., S.E. Thomson, K.P. Pollock, L. Youwei, and D.J. Mead. 2005. Water potential and gas exchange did not reflect performance of Pinus radiata D. Don in an agroforestry system under conditions of soil-water deficit in a temperate environment. Plant Soil 275: 195-206.
121. Zamora, D., S. Jose, and P.K.R. Nair. 2006. Interspecific interaction in a pecan-cotton alleycropping system in the southern United States: The production physiology. Can. J. Bot. 84: 1686-1694.
122. Zamora, D.S., S. Jose, and P.K.R. Nair. 2007. Morphological plasticity of cotton roots in response to interspecific competition with pecan in an alley cropping system in the southern United States. Agrofor. Syst. 69: 107-116.