Abstract : Establishment of ornamental and aesthetic plants in hot, arid conditions of India is difficult due to the prevailing climatic, edaphic and biotic factors。 Effect of turfgrass on the growth of ornamental plants in hot arid conditions has not been studied so far anywhere in the world。 A study was conducted on the campus of Arid Forest Research Institute, Jodhpur, India to assess the performance of a few ornamental plant species in combination with turfgrass and without turfgrass with respect to different soil tilling intervals。 Growth of plants was better with turfgrass than without turfgrass。 We suggest adopting a soil tilling interval of 30 days to achieve optimum growth of ornamental plant species in terms of height and crown diameter。 Our results can help reduce labor costs and achieving better landscapes in fewer days in hot urban conditions of Indian sub continent。83495

Keywords:  ornamental plants; soil working interval; Thar Desert; turf grass; urban forestry & urban greenery

Introduction 

Raising plantations, especially of ornamental species in arid urban regions, is a difficult task, and obtaining good growth in such circumstances is even more challenging。 The hostile and harsh environment of the hot Thar Desert of India, for example, includes extremes of temperature, low and erratic mean annual rainfall, and very high rates of evapotranspiration as the main features that reduce plant growth and survival (Chaudhry et al。 2010)。 A technically sound and well managed landscaping of these areas may overcome the problems of survival and growth。 Landscaping of such areas by planting trees and shrubs with grass lawns not only creates naturalistic and picturesque effects but improves environmental quality and the life style of people (Nielson 1978; Beard et al。 1994)。 A healthy and multifunctional green infrastructure is one of the basic requirements in today’s life, especially in arid hot regions。 It includes planning, designing, selection of plant species according to site and water requirements, proper planting technique, and scientific management (Cheng et al。 2000)。

Urban green spaces have many benefits, for example, reducing noise pollution in cities (Fang et al。 2005; Bolund et al。 1999), reducing storm water runoff (Xiao et al。 1998), alleviating the intensity of heat islands (Potchter et al。 2008), increasing carbon sequestration (Johnson et al。 2003; McPherson et al。 2005; Pataki et al。 2006), reducing air pollution (Nowak 1994; McPherson et al。 1998; Jim et al。 2009) and maintaining biopersity (Attwell 2000)。 In addition to these, proximity of public parks/gardens, natural areas, golf courses, and tree avenues can have a significant effect on real estate values (Luttik 2000; Bolitzer et al。 2000)。 Research in European cities showed that green spaces provide better environment for commercial and residential purposes (Konijnendijk 1999, 2001)。 Turf grasses in combination with trees are helpful in stabilizing atmospheric dust, controlling soil erosion, and absorbing air-polluting gases。 Therefore, planting of trees and turf together not only provides protection from hot and desiccating winds and the invasion of sand in arid regions but also contributes to improvements in our physical and mental health。   

High air temperatures, common in hot arid climates, cause heat stress which decreases the capacity of turfgrass to fix carbon into sugars and other carbohydrates (Stier 2009)。 Therefore, it is always beneficial to raise turf in combination with trees and shrubs in such circumstances to achieve their better growth (Shashua-Bar et al。 2009)。 Trees, shrubs and turfgrasses all require water, sunlight and root space for growth, particularly below ground。 During initial growth stages, the roots of most tree species are spread near the ground surface over two to three feet from the trunk while water absorbing roots are in the top at 15。24 cm of soil。 Grass roots ordinarily occupy greater soil volume than tree roots to compete for water and nutrients, especially around young trees and can impede tree growth during early stages。 Grass roots are sometimes so vigorous that tree roots can not grow in the same soil。 Grass roots also grow very fast, compared to roots of trees。 These roots can quickly and thoroughly penetrate every part of the soil for extracting the all available resources ahead of other plants。 Watson (2004) showed that turf grass could drastically reduce the amount of tree roots present in the top few inches of soil。 Removing of grass from pits of young plants eliminates competition and stimulates growth of young trees。 However, time intervals for soil tilling to remove grass around young plants in a hot arid landscape has not been discussed yet in the scientific literature related to arid zone plantation。 Considering cost effectiveness of any plantation model or landscape design, suitable management practices are needed (Suleiman et al。 2002)。 With this idea in view, we undertook a study of landscape plants in the urban hot arid region of the Thar Desert in Jodhpur city of India and conducted an experiment on management practices of soil tillage for better growth of plants。 The main objective of the study was to assess the optimum soil tilling interval for ornamental and aesthetic plants raised with and without turf grass in hot arid conditions of the Indian subcontinent。 Our findings can help develop aesthetically rich landscapes in hot arid conditions of this region with reduced labor inputs and related expenditures。