Microclimate modifications, growth and yield of intercrops under Hardwickia binata Roxb. based agroforestry system (Mikroklimaa ¨ nderungen, Wachstum und Ertrag von Unterbaukulturen in Agroforestry-Systemen mit Hardwickia binata Roxb.) ARUN K. SHANKER, RAM NEWAJ, P. RAI, K. R. SOLANKI, K. KAREEMULLA, R. TIWARI, & AJIT National Research Centre for Agroforestry (NRCAF), Pahuj Dam, Uttar Pradesh, India (Received 29 July 2004; accepted 16 September 2004) Abstract An experiment was conducted by planting Hardwickia binata Roxb. at 200, 400 and 800 trees ha 7 1 , intercrops viz., Brassica campestris (mustard) and Glycine max (soybean) were sown from the second year onwards in winter and summer respectively at the National Research Centre for Agroforestry, Jhansi, U.P., India with the objectives of evaluating agrosilvicultural potential of the system and to study the effect of tree densities on ecophysiology of understorey crops. Tree growth was affected by both density and intercrop in the initial years of growth. Photosynthetic photon flux density (PPFD) available to the intercrops reduced with increasing densities. Transpiration rate and stomatal conductance in intercrops decreased due to the presence of trees. No significant changes in leaf temperature were observed till the fifth year of the growing season. Yield was significantly higher in pure crop in comparison with all the densities in mustard. Soybean yield under 200 trees ha 7 1 was comparable to that of the pure crop. Trees at the density of 200 trees ha 7 1 provided a conducive microenvironment to the intercrops. Keywords: Transpiration rate, stomatal conductance, agroforestry, crop yield, understorey crops, Hardwickia binata, tree density Introduction Gaining production advantages using diversity of crop species within a cropping system has been one of the main goals of agroforestry. The importance of agrosilviculture in attaining this goal had been clearly shown by several workers (Griffin & Maller, 1999; 1999; Trenbath, 1999). Hardwickia binata Roxb. of the family leguminosae, subfamily caesalpinoidae is a Correspondence: Arun K. Shanker, Scientist (Plant Physiology) National Research Centre for Agroforestry (NRCAF), Pahuj Dam, Gwalior Raod, Jhansi-284003, Uttar Pradesh, India. E-mail: arunshanker@mailcan.com Archives of Agronomy and Soil Science June 2005; 51(3): 281 – 290 ISSN 0365-0340 print/ISSN 1476-3567 online # 2005 Taylor & Francis Group Ltd DOI: 10.1080/03650340500053407