Diversity of Shade Trees and Their Influence on the Microclimate of Agro-Ecosystem and Fruit Production of Gulapasir Salak (Salacca Zalacca Var
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International Journal of Basic & Applied Sciences IJBAS-IJENS Vol:12 No:06 214 Diversity of Shade Trees and Their Influence on the Microclimate of Agro-Ecosystem and Fruit Production of Gulapasir Salak (Salacca Zalacca var. Amboinensis) Fruit I Ketut Sumantra, Sumeru Ashari, Tatik Wardiyati, Agus Suryanto Abstract— The presence of shade trees in salak tree Karangasem regency in cultivating the Gulapasir salak trees plantation is necessary as the plant was unable to defend the make other areas interested to do the same. The Gulapasir salak sunlight. The study was aimed to identify the diversity of shade trees are now planted and cultivated in other districts in Bali, trees and their influences on the microclimate and Gulapasir which one of them is Tabanan [2]. salak fruit production in agro-ecosystem in Karangasem Production problems faced by Gulapasir salak farmers in the (original planted area) and Tabanan (new area development). new area, especially in Tabanan, was low fruit yield. Weight The research employed plot methods placed in purposive per fruit, weight of fruit per bunch, and the number of fruits per random sampling on high altitudes 450-750 m above sea level bunch are 7.11%, 31.64%, and 25%, respectively, lower (asl) in Karangasem and Tabanan. The parameters measured compared with production in Sibetan Karangasem [3]. Growing were plant density, frequency, dominancy, Important Value elevation influences the Gulapasir salak fruits. The heaviest Index (IVI), Diversity Index (H), microclimate, fruit number, and fruit weight was produced by plants grown at an altitude of weight of fruits. The differences of shading plant density and its 501-600 m above sea level (asl). Low fruit yield in Tabanan was influences on microclimate were analyzed using t-test, and the relationship between light interception and the number and also due to the low intensity level of cultivation of the trees, weight of fruits was analyzed using regression analysis. The especially in fertilizing, irrigation and shade trees settings [4]. results showed that the density of shade trees and population of Naturally, the flowers of Gulapasir salak trees appear three to salak trees in Karangasem and Tabanan was different. The four times in a year [2, 5-7]. Flowering and pollination of fruit difference in light interception due to different plant densities crops is influenced by environmental factors, particularly the in each zone in Tabanan and Karangasem only caused a microclimate [8] such as temperature, humidity, light intensity decrease in air temperature significantly in the zone 650-750 m and rainfall [9, 10]. Rai et al. [6] found that fruit yield in asl, so the number and weight of fruit produced was lower than Gulapasir salak trees has a positive correlation with humidity, the other two zones. but a negative correlation with sunlight intensity. It means that the plants only need portion of sunlight. In fact, they need 50- Index Term— salak trees, Gulapasir, shading plant, diversity, 70% sunlight [5, 11]. Therefore, sunlight reduction is essential microclimate. in Gulapasir salak tree plantation [12]. I. INTRODUCTION The shade trees and salak trees together will form a certain GULAPASIR salak trees (Salacca zalacca var. amboinensis) are agro-ecosystem in the area. Agro-ecosystem is defined as an originated from Sibetan Karangasem area that began to be ecosystem that is modified and used directly or indirectly by cultivated in 1989 from about 133 trees [1] amounted to 1.5 human being to meet the demand for food and or clothing [13]. million trees in 2007 (Bappeda Karangasem, 2007) or about 25% Therefore, the use of shading plant on the salak trees is of the total population of salak trees in Karangasem regency expected: (1) to increase the productivity in accordance with (Department of Agriculture Bali, 2009). The success of the carrying capacity of the agro-ecosystem, (2) to gain production stability, (3) to achieve continuity of harvest I K. Sumantra is with the Postgraduate Program, Faculty of without lowering the carrying capacity of the agro-ecosystem, Agriculture, Brawijaya University, Jl. Veteran 2, Malang 65145, East and (4) to improve sustainability that is to balance the needs of Java, Indonesia; and the Dept. of Agrotechnology, Faculty of the environment, economy and social culture [13]. Agriculture, Mahasaraswati University, Jl. Kamboja 11A, Denpasar, Indonesia (corresponding author; phone: +62-812; e-mail: Our inventory on types of covering crops in Gulapasir salak [email protected]). tree farming system in the new development area in Bali found S. Ashari, T. Wardiyati, and A. Suryanto are with the Faculty of that each agro-ecosystem zone has different types of shade Agriculture, Brawijaya University, Jl. Veteran 2, Malang 65145, East trees. The plant species commonly used as building material Java, Indonesia. and for land conservation such as Sengon (Albisia falcate), 1213906-6464- IJBAS-IJENS @ December 2012 IJENS I J E N S International Journal of Basic & Applied Sciences IJBAS-IJENS Vol:12 No:06 215 Suren (Toona sureni Merr) and Gempinis (Melia azedarach L.) conducted to determine the dominant value of shade trees, largely dominate the zone 600-800 m asl. Shade trees of calculated by the square method. Based on the inventory and commercial fruits like Mangosteen (Garcinia mangostana L.), the calculation of the population, each plot was then analyzed Durian (Durio zibethinus Murr), and jackfruit (Artocarpus to determine the relative frequency, relative density, relative heterophylla L.) were found in the zone 400-600 m asl. Crop dominance and importance value index (IVI) according to the species used in industry such as clove (Eugenia aromatica methods used by Arrijani [21] as follows: OK) was found in the zone 501-800 m asl [4]. The different in • Relative Frequency (RF) is the appearance frequency of a crop species in the agro-ecosystems are strongly influenced particular species divided by all species and multiplied by by ecological conditions, its economic benefits and its purpose 100%. of natural resources conservation [13, 14]. • Relative Density (RD) is the density of a species divided by So far, the diversity of covering crops and their effects on the density of all species and multiplied by 100%. the microclimate and production of Gulapasir salak fruits in • Relative Dominance (RDo) is the dominance of a species Karangasem and Tabanan areas is unknown. Therefore, it is divided by the dominance of all types and multiplied by important to conduct a research in this area since variation in 100%. agro-ecosystems affect the production of salak fruits [15]. • Importance Value Index (IVI) is the summation of the relative Provision of shade trees to salak trees gives several frequency, relative density and relative dominance. IVI benefits, among others: (1) to modify the micro-climate such as describes the percentage of influence that is formed by a air and soil temperatures [13], (2) to prevent crop damage due plant species to its ecology. The higher IVI of a species to high winds [12], (3) to conserve flora and fauna [16], (4) to shows the more dominant of its influence. protect and improve soil’s physical and chemical properties [17]. Species diversity index (H) was calculated by the formula: However, covering crops planted in mixed with salak trees face many obstacles, including competition for sunlight, n nnii H i1 log (1) competition for water, and competition for nutrient when these NN elements are limited [18]. The level of competition depends on where H is the Shannon-Wiener index of species diversity, n is the characteristics of the plants, the soil and the level of i number of individuals (or Importance Value Index-IVI) of the i- management [19, 20]. It is therefore necessary to study the th species, and N is total number of individuals (or IVI) of all diversity of covering crops and their effects on the the species in site. microclimate and production of salak fruits. This information is Distribution pattern of each type of shade trees was important for plantation management to reduce the negative analyzed using the ratio between the standard deviation (SD) impacts and to create ideal conditions for the growth of salak and the average value [21], with the following criteria: trees and maintain sustainable agro-ecosystems. • If the value of SD / mean = 1, then the type of shade trees This paper describes our study results in identifying species was distributed randomly, of shading trees for Gulapasir salak trees in Tabanan and • If the value of SD / mean> 1 the type of shade trees was Karangasem and how they influence the microclimate and distributed in cluster, and production of Gulapasir salak fruits in Tabanan and • If the value of SD / mean <1 then the type of shade trees was Karangasem.. regularly distributed. The microclimate included sunlight intensity measured using II. MATERIALS AND METHODS lightmeter type LX-101A, observation under the canopy and The research was carried out for 4 months from December - upper the canopy of salak trees were conducted at 12.00 noon March 2010 in Tabanan and Karangasem, Bali, Indonesia at the during maximum irradiation. After obtaining the light intensity, altitude of 450-750 m above sea level (asl). Based on the percentage of light intercepted was acquired. The light development of Gulapasir salak trees in Karangasem and intercepted value was calculated using equation: Tabanan, the experiment field was divided into 3 sub altitude zones, namely zone I (450-550 m), zone II (551-650 m), and zone II III (651-750 m asl). up un It 100% (2) The plot dimension was 20 m × 20 m for the observation of Iup the tree strata and 10 m × 10 m for trees with pole strata. Based where It is the intercepted value of light, Iup is intensity of light on stem diameter, the plant strata were classified into two: Ø > in upper canopy, and Iun is intensity of light in under the 30 cm (tree strata) and Ø 10 - 30 cm (pole strata).