A scholaris attained maximum height (297。0 cm), followed by B。 glabra (250。93 cm) and T。 stans (248。33 cm), significantly taller than others (p<1%)。 Maximum height increase from 2006 (209。07 cm) was recorded for A。 scholaris, followed by B。 glabra (191。76 cm)。 T。 stans also performed well and attained good growth (157。40 cm)。 E。 paricata attained the lowest increase in height (62。54 cm) (Table 1)。 Crown diameter was greatest for B。 glabra (260。30 cm), followed by A。 scholaris (234。87 cm) and T。 stans (231。77 cm), all significantly greater than other species。   

Discussion   

Suppression of woody plants by grasses has been widely reported; but few studies investigated the factors causing reduced growth and poor appearance of ornamental trees and shrubs planted in areas with turfgrass (Fales et al。 1981)。 In many landscapes of hot, arid, urban areas, plantations die due to lack of sound management practices。 Plants in various turfgrass areas do not attain the desired growth even when receiving sufficient irrigation because they are not managed technically and their growth is stunted。 Hendrickson (2008) found significant root growth differences occurring in turfgrass-tree combinations in a study conducted in Utah Intermountain west region with dry winds and sparse rainfall。 Seedling survival decreased significantly due to competing grass cover (Bush et al。 1990; Wagner et al。 1999)。 Neither of these studies was conducted in a hot, arid region。 Nielsen and Wakefield (1978) observed suppression of growth of some ornamental shrubs planted in combination with turfgrass。 A literature survey of scientific databases including SCOPUS, GOOGLE, and SCHOLAR, showed no study of the effect of soil tilling interval on the growth and development of ornamental and aesthetic plants raised in combination with turfgrass in semi arid and arid regions。 Therefore, our study was conducted in hot arid region of India。 

Plants in turfgrass areas attained significantly greater height and crown diameter at 15 day and 30 day STIs as compared to those without turfgrass, whereas these attained lowest growth at 45 day STI。 This might be due to grass minimizing moisture loss, leaving more moisture for plant growth。 However further research is required on the effects of some parameters, such as moisture availability, reduction in temperature, improvement in relative humidity, and soil properties in the presence of turfgrass and interactions of these factors。 We recorded no significant differences in terms of height and crown diameters of plants at 15 day and 30 day STI, whereas the difference was found to be significant for soil tilling at 15 days and 45 days in both plantation models (with and without turfgrass)。 We recorded significant declines in height and crown diameter for plants with turfgrass at 45 day STI in comparison to those at 30 day STI (Fig。 1)。 Without turfgrass, crown diameters of plants at 45 day STI were significantly lower than at 30 day STI。 We hypothesize that the roots of turfgrass impeding the growth of plants due to competition for moisture and soil nutrients at longer STIs。 We conclude that soil tilling at 30 day intervals was the best practice to obtain greater plant height and crown diameter。 If soil tilling is performed in plant pits during the initial establishment stage, it adds to proper growth of plants。 

Soil tilling at 30 day intervals could result in increased plant height of 13% and crown diameter of 7% in turfgrass areas in comparison to 45 day tilling intervals。 We conclude that the growth of plants was significantly better with turfgrass than without turfgrass。 Plants planted in turfgrass areas attained 8% more height and 4% more crown diameter at 30 day tilling intervals in comparison to plants planted outside turfgrass areas at 45 day intervals。 Taking both plantation models together, height and crown diameter showed significant increases at 7% and 5%, respectively, at tilling intervals of 30 day compared to 45 day (Table 1)。