International Journal of Basic & Applied Sciences IJBAS-IJENS Vol:12 No:06 214

Diversity of Shade 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 Karangasem regency in cultivating the Gulapasir salak trees plantation is necessary as the 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 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, ; 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 commonly used as building material Java, Indonesia. and for land conservation such as Sengon (Albisia falcate),

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Suren ( 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  i1  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). These two canopy. strata were selected for the homogeneity and Air temperature and humidity were obtained by measuring representativeness of the sample in each sub zone that was air temperature and humidity under the canopy of salak trees observed. using a thermo-hygrometer (thermometer and hygrometer– The analysis of importance (importance value index/IVI) was TA218c). The number and weight of fruit were measured from

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36 plots of six trees during the main harvest at the end of Karangasem, Erythrina sp. got the highest IVI that was 66.52% February. Salak fruit samples were selected from plants that followed by Musa sp. (58.36%), Durio zibethinus (25.44%), have been fruiting before, have a uniform morphology, age and Albisia falcate (24.93%), Cocos nucifera (24.550%), Garcinia cultivation actions provided. mangostana (22.75%), and Glyricidia sepium (20.745%). The A t-test was used to determine the differences in high IVI of the shading plant was caused by the value of RD, microclimate, the quantity of fruit and the fruit weight due to RF and RDo which was also high (Table I). The diversity index differences in the number of shade trees and the agro- (H) of the shade trees in Tabanan was higher (1.072) than ecosystem salak trees in the original Sibetan Karangasem area those in Karangasem (0.958). This difference occurred due to and the new plantation area. Relationship between the total species found in Karangasem was 13 species, while in microclimate variables and the number of salak trees was Tabanan it was 16 species. analyzed by correlation and regression techniques. In three sub-zones observed in Tabanan, it was known that Coffea sp. was dominant. It can be seen from its high IVI value III. RESULTS AND DISCUSSION in all sub-zones, 50.52% (sub-zone III), 68.07% (sub-zone II) We identified some 20 shade trees species, scattered in and 81.32% (sub-zone I), respectively (see Table 2). Besides, Karangasem (13 species) and Tabanan (16 species) as the Theobroma cacao, Durio zibethinus, Musa paradisiaca, tabulated in Table I. Nine species were equally common in both Erythrina variegate, and Garcinia mangostana were also areas. There were seven shading plant species in Tabanan that found in all sub-zones. In Karangasem Erythrina variegata were not found in Karangasem, namely Coffea sp., Theobroma was dominant only in sub-zones I and II, while sub-zone III cacao L., Eugenia aromatica OK, Melia azedarach L., was dominated by Musa sp. Both types of shade trees had the Aleurites moluccana Willd., Artocarpus heterophylla, and highest IVI value between 49.1% – 66.67% for Erythrina Hibiscus tiliaceus. Meanwhile, there were four shading plant variegate, and 45.88% – 63.62% for Musa sp. Cocos nucifera, species in Karangasem that were not found in Tabanan, Durio zibethinus Murr, and Garcinia mangostana also namely Nephelium lappaceum L., Lansium domesticum, showed IVI value greater than 20%, but the order of the three Baccaurea racemosa (Reinw. Ex. Bl.) MA, and sp. types of IVI values were not consistent across the sub-zones Coffea sp., Theobroma cacao, Musa sp., Erythrina sp., (Table II). Durio zibethinus, and Leucaena glauca were the species that dominated the salak tree plantation in Tabanan area with an importance value index more than 20% (Table I). In

T ABLE I T HE AVERAGE OF RELATIVE DENSITY (RD), RELATIVE FREQUENCY (RF), RELATIVE DOMINANCE (RDO) AND IMPORTANCE VALUE INDEX (IVI) OF SHADE TREES IN GULAPASIR SALAK TREE AGRO-ECOSYSTEM IN T ABANAN AND KARANGASEM (N = 32 PLOTS). No Tabanan Karangasem Name of Shading Plant . RD% RF% RDo% IVI% H RD% RF% RDo% IVI% H 1 Coffea sp. 45.86 9.630 13.038 68.532 –0.146 – – – – – 2 Theobroma cacao L. 9.023 9.630 9.346 30.899 –0.102 – – – – – 3 Musa paradisiaca L. 9.774 13.33 4.384 27.491 –0.095 34.95 16.98 6.426 58.359 –0.138 4 Erythrina variegata L. 6.767 9.630 9.346 25.742 –0.092 29.13 16.98 20.41 66.523 –0.145 5 Durio zibethinus Murr. 3.759 7.407 13.535 24.702 –0.090 4.369 8.491 12.57 25.436 –0.091 6 Leucaena glauca Benth. 3.008 13.33 4.384 20.724 –0.080 0.971 1.887 0.510 3.368 –0.022 7 Glyricidia sepium. 6.767 8.889 2.922 18.578 –0.074 7.282 10.37 3.086 20.745 –0.080 8 Cocos nucifera. 4.511 8.889 4.574 17.974 –0.073 6.311 12.26 5.975 24.550 –0.089 9 Garcinia mangostana L. 2.256 4.444 9.985 16.685 –0.070 2.913 5.660 14.17 22.748 –0.085 10 Albisia falcate. 1.504 2.963 10.289 14.756 –0.065 3.883 7.547 13.50 24.933 –0.090 11 Eugenia aromatica O.K.. 3.008 5.926 1.948 10.882 –0.052 – – – – – 12 Melia azedarach L 1.128 2.222 6.575 9.925 –0.049 – – – – – 13 Toona sureni (Bl.) Merr. 0.752 1.481 3.683 5.917 –0.034 1.942 3.774 8.577 14.293 –0.063 14 Aleurites moluccana Willd. 0.376 0.741 2.192 3.308 –0.022 – – – – – 15 Artocarpus heterophylla 0.752 0.741 0.548 2.041 –0.015 – – – – – 16 Hibiscus tiliaceus. 0.752 0.741 0.351 1.843 –0.014 – – – – – 17 Nephelium lappaceum L – – – – – 3.398 6.604 8.496 18.498 –0.075 18 Lansium domesticum – – – – – 2.427 4.717 2.051 9.195 –0.046 19 Baccaurea racemosa (Reinw. – – – – – 0.485 0.943 0.337 1.766 –0.013 Ex. Bl.) M.A 20 Swietenia sp – – – – – 1,942 3,774 3,873 9,588 –0,048 Total H (diversity index) 1.072 Total H (diversity index) 0.958

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T ABLE II RELATIVE DENSITY (RD), RELATIVE FREQUENCY (RF), RELATIVE DOMINANCE (RDO) AND IMPORTANCE INDEX VALUE (IVI) OF SHADE TREES IN GULAPASIR SALAK TREE AGRO-ECOSYSTEM IN T ABANAN AND KARANGASEM (N = 32 PLOTS). Tabanan Karangasem Sub Zone Name of Shading Plant RD RDo RD RF (%) IVI (%) RF (%) RDo (%) IVI (%) (%) (%) (%) I : Coffea sp. 51.61 15.38 14.33 81.32 – – – – 450– 550 m asl Theobroma cacao L. 16.13 12.82 14.33 43.28 – – – – Durio zibethinus Murr. 4.30 10.26 18.71 33.27 4.41 9.38 15.33 29.12 Leucaena glauca Benth. 5.38 12.82 10.53 28.72 – – – – Musa paradisiaca L. 6.45 15.38 4.68 26.51 30.88 18.76 4.08 53.73 Cocos nucifera. 6.45 15.38 6.74 28.57 8.82 18.76 4.54 32.13 Garcinia mangostana L. 1.08 2.56 18.71 22.35 4.41 9.38 22.43 36.22 Glyricidia sepium. 5.38 10.26 4.68 20.31 10.29 12.51 3.02 25.82 Erythrina variegata L. 3.23 5.13 7.31 15.66 35.29 18.76 12.62 66.67 Toona sureni (Bl.) Merr. – – – – 2.94 6.25 26.32 35.53 Nephelium lappaceum L. – – – – 2.94 6.25 9.97 19.16 II : Coffea sp. 49.02 13.04 6.01 68.07 – – – – 551–650 m asl Garcinia mangostana L. 4.90 10.87 19.46 35.24 2.99 4.88 19.63 27.49 Durio zibethinus Murr. 3.92 8.70 16.69 29.31 5.97 9.76 13.41 29.14 Aleurites moluccana Willd. 0.98 2.17 24.03 27.18 – – – – Musa paradisiaca L. 8.82 13.04 2.67 24.54 28.36 14.64 2.88 45.88 Erythrina variegata L. 6.86 10.87 6.01 23.74 28.36 14.64 9.85 52.85 Cocos nucifera. 5.88 13.04 4.51 23.44 8.96 14.64 3.97 27.57 Theobroma cacao L. 4.90 8.70 9.14 22.74 – – – – Glyricidia sepium. 4.90 8.70 2.67 16.27 5.97 7.32 2.64 15.93 Leucaena glauca Benth. 2.94 6.52 6.01 15.47 – – – – Eugenia aromatica O.K.. 1.96 4.35 2.67 8.98 – – – – Nephelium lappaceum L. – – – – 7.46 12.20 11.04 30.70 Albisia falcate. – – – – 2.99 4.88 16.49 24.36 Lansium domesticum – – – – 2.99 4.88 16.49 24.36 Toona sureni (Bl.) Merr – – – – 2.99 4.88 13.63 21.49 Baccaurea racemosa – – – – 1.49 4.88 2.88 9.26 (Reinw. Ex. Bl.) M.A. III: Coffea sp. 31.58 13.04 5.90 50.52 – – – – 651-770 m asl Albisia falcate. 5.26 8.69 17.27 31.23 8.22 16.67 15.83 40.72 Musa paradisiaca L. 14.47 13.04 1.64 29.15 43.84 16.67 3.12 63.62 Erythrina variegata L. 9.21 13.04 6.54 28.79 23.29 16.67 9.45 49.41 Melia azedarach L. 3.95 6.52 14.72 25.19 – – – – Eugenia aromatica O.K.. 7.89 13.04 3.68 24.61 – – – – Glyricidia sepium. 10.53 8.69 1.64 20.85 5.97 7.32 2.64 15.93 Theobroma cacao L. 5.26 8.69 5.90 19.86 – – – – Toona sureni (Bl.) Merr. 2.63 4.35 12.37 19.35 2.74 5.56 13.08 21.38 Durio zibethinus Murr. 2.63 4.35 11.92 18.90 2.74 5.56 13.08 21.38 Garcinia mangostana L. 1.32 2.17 12.82 16.31 1.37 2.78 22.11 26.26 Artocarpus heterophylla L. 2.63 2.17 3.68 8.48 – – – – Hibiscus tiliaceus. 2.63 2.17 2.36 7.16 – – – – Swietenia sp – – – – 5.48 11.11 10.60 27.19 Cocos nucifera. – – – – 1.37 2.78 3.27 7.42 Lansium domesticum – – – – 2.74 5.56 3.27 11.57 Leucaena glauca Benth. – – – – 2.74 5.56 2.09 10.39

The shade trees species that have the highest IVI like average individual species showed a lower ratio of 1 (Table III). Erythrina sp. and Musa sp. were the type that spreads evenly The result of the analysis showed that the presence of shade in all three sub-zones. It indicated that they had the ability to trees was largely determined by ecological conditions and its adapt to changes in temperature and altitude in the range 450- benefits to the people who manage it. 770 m asl. This was relevant with the area of Tabanan and The spreading characteristics of shade trees in Tabanan can Karangasem. These types of shade trees spread regularly so be classified into 2 types: regular and cluster spreading. that it could be found in each sub-zone ranging from 450 m – Species of shade trees with regular spread (SD/mean < 1) were 770 m above sea level. It can be seen from the results of the Durio zibethinus, Musa sp., Coffea sp., cacao, Erythrina analysis of the ratio between the standard deviation of the variegate, and Glyricidia sepium. While species with cluster

1213906-6464- IJBAS-IJENS @ December 2012 IJENS I J E N S International Journal of Basic & Applied Sciences IJBAS-IJENS Vol:12 No:06 218 spread (SD/mean > 1) were mangosteen, Leucaena glauca, Leucaena glauca, Toona sureni, Albisia falcate, Nephelium Eugenia aromatica, Aleurites moluccana, Toona sureni, lappaceum, Lansium domesticum, Baccaurea racemosa, and Hibiscus sp., Artocarpus heterophylla L., and Melia azedarach. Swietenia were spread in cluster. Glyricidia sepium was found For those in Karangasem, Erythrina lithosperma, Musa distributed randomly (Table III). paradisiaca, coconut, mangosteen, and Durio zibethinus were found in altitude of 450 -770 m and spread regularly; and T ABLE III T HE DISTRIBUTION PATTERNS OF SHADE TREES ON AGRO-ECOSYSTEM GULAPASIR SALAK TREE, ZONE 450 -770 M ASL, IN T ABANAN AND KARANGASEM. Tabanan Karangasem Name of Shading Plant SD/ Spreading SD/ Spreading SD Mean SD Mean Mean Type Mean Type Garcinia mangostana L. 0.49 0.33 1.46 Cluster 0.51 0.55 0.92 Regularly Durio zibethinus Murr. 0.51 0.56 0.92 Regularly 0.51 0.55 0.92 Regularly Leucaena glauca Benth. 0.51 0.44 1.15 Cluster 0.32 0.11 2.91 Cluster Musa paradisiaca L. 0.51 1.44 0.35 Regularly 1.28 4.00 0.32 Regularly Coffea sp. 2.10 6.78 0.31 Regularly – – – – Theobroma cacao L. 1.19 1.33 0.89 Regularly – – – – Erythrina variegata L. 0.91 1.00 0.91 Regularly 0.91 3.33 0.27 Regularly Glyricidia sepium. 0.91 1.00 0.91 Regularly 0.86 0.83 1.03 Random Cocos nucifera. 0.49 0.44 1.11 Cluster 0.46 0.72 0.64 Regularly Eugenia aromatica O.K.. 0.51 0.44 1.15 Cluster – – – – Aleurites moluccana Willd. 0.24 0.06 4.24 Cluster – – – – Toona sureni (Bl.) Merr. 0.32 0.11 2.91 Cluster 0.43 0.22 1.93 Cluster Hibiscus tiliaceus. 0.47 0.11 4.24 Cluster – – – – Artocarpus heterophylla L. 0.47 0.11 4.24 Cluster – – – – Albisia falcate. 0.43 0.22 1.93 Cluster 0.51 0.44 1.15 Cluster Melia azedarach L 0.38 0.17 2.30 Cluster – – – – Nephelium lappaceum L – – – – 0.50 0.39 1.29 Cluster Lansium domesticum – – – – 0.46 0.28 1.66 Cluster Baccaurea racemosa (Reinw. Ex. Bl.) – – – – 0.24 0.06 4.24 Cluster M.A. Swietenia sp – – – – 0.43 0.22 1.93 Cluster

Tables I and II showed that the shade trees of coffee and zones in Tabanan. cacao in Tabanan were more dominant than in Karangasem. Plant density was positively correlated with light Before Gulapasir salak trees were widely cultivated in Tabanan, interception (r = 0953**) and humidity (r = 0288) and this area was the centre of dry land crops cultivation such as negatively correlated with air temperature (r = –0721**). High vanilla, coffee, clove, and cacao. The falling sale of clove and density causes higher interception to light. Fig. 1b shows that vanilla encourages the farmers in this area to convert to the value of interception of light in Karangasem for each sub Gulapasir salak trees for the price was very promising. Unlike in zone was higher and significantly different compared to the the original plantation area in Karangasem, Tabanan was a same sub-zone in Tabanan (t = 5.04, p > 0.05 sub zone I, t = moderate area having no special characteristic in agricultural 4.31, p > 0.05 sub zone II and t = 8.74, p > 0.05 sub zone III). commodity other than salak trees, so that the shade trees were This shows that the interception of light was strongly more on plants which were planted in accordance with the influenced by the level of shade by plants associated with needs of farmers and agro-climate conditions. Hence, the plant density [23]. Gulapasir salak tree in Karangasem was intercropped with Increased light interception in the sub zones I - II in other perennial crops, such as coconut, Durio zibethinus, Karangasem and Tabanan did not cause a noticeable banana, and Erythrina sp. [22]. difference to the temperature (t = 1.78, p <0.05 sub zone I) and The presence of shade trees and salak trees showed (t = 0.96, p < 0.05 II) but was significantly different in the sub- different effects on the microclimate on salak Gulapasir tree zone III (t = 2.83, p > 0.05). For humidity, the increased light plantations. Total density (salak trees and shade trees) on the interception in each sub zone in Karangasem and Tabanan area of 100 m2 in the sub-zones I and III in Karangasem and showed no significant difference (t = 0.43, p < 0.05, t = 0.18, p < Tabanan was different (t = 6.33, p > 0.05 and t = 3.79, p > 0.05), 0.05, t = 0.05, p < 0.05 each sub zone I, II and III). However, it is while was not significant different in sub-zone II (t = 0.83, p < clearly seen in Fig. 1b the tendency that increased light 0.05). Fig. 1a shows the total density of plants in Karangasem interception resulted in the decrease in the average air in sub zones I, II and III was 22.62%, 3.39% and 18% higher, temperature and increase in the humidity. The higher the respectively, compared with the total density in the same sub- interception of light, the lower the temperature under the salak

1213906-6464- IJBAS-IJENS @ December 2012 IJENS I J E N S International Journal of Basic & Applied Sciences IJBAS-IJENS Vol:12 No:06 219 tree canopy (r = –0698**) and the higher the air humidity (r = 0370). Microclimate differences in each zone indicated diverse effects on the number of fruits per bunch, fruit weight per fruit, and fruit weight per plant (Fig. 2). The number of fruits per bunch and fruit weight per fruit in sub zones I and II Karangasem and Tabanan was different (t = 2.21, p > 0.05 and t = 3.46, p > 0.05 for the number of fruits) and (t = 4.73, p > 0.05 and t = 4:04, p > 0.05 for fruit weight per fruit). While the number of fruits per bunch, fruit weight per fruit and fruit weight per tree in sub zone III Karangasem and Tabanan were not significantly different (Fig. 2).

Fig. 2. The number of fruits per bunch, fruit weight per fruit, and the fruit weight per tree in sub zones I, II, III Karangasem (Kr) and Tabanan (Tbn). The increase of light interception negatively affects to the number of fruits per bunch and the weight of fruit per tree in Tabanan and Karangasem (Figs. 3 and 4).

Fig. 1a. The number of shade trees and salak trees per 100 m2 in sub- zones I, II, III Karangasem (Kr) and Tabanan (Tbn).

Fig. 3. The relationship between light interception and the number of fruit per bunch in Tabanan (a) and Karangasem (b). Fig. 1b. Interception of light, humidity and air temperature in sub zones I, II, III, Karangasem (Kr) and Tabanan (Tbn).

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caused a decrease in air temperature significantly in the zone 650-750 m above sea level. Thus, the number and weight of fruit produced were lower than those in the other two zones.

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contrasting an open-grown and a shaded coffee plantation," Agroforestry Systems, vol. 72, pp. 103-115, 2008. [18] Hairiah, K. Widianto, S. R. Utami, and B. Lusiana, WaNuLCas, model simulasi untuk sistem agroforestri. Bogor: International Centre for Research in Agroforestry. Southeast Asian Regional Research Programme, 2002 (in Indonesian). [19] J. Beer, "Advantages, disadvantages and desirable characteristics of shade trees for coffee, cacao and tea," Agroforestry Systems, vol. 5, pp. 3-13, 1987. [20] J. Beer, R. Muschler, D. Kass, and E. Somarriba, "Shade management in coffee and cacao plant ations," Agroforestry Systems, vol. 38, pp. 139-164, 1997. [21] Arrijani, "Struktur dan komposisi vegetasi zona Montana Taman Nasional Gunung Gede Pangrango," Biodeversitas, vol. 9, pp. 134-141, 2008 (in Indonesian). [22] Sukewijaya, I. N. Rai, and Mahendra, "Development of salak bali as an organic fruit," As. J. Food Ag-Ind., vol. Special Issue, pp. 37- 43, 2009. [23] E. A. Curry, "Canopy development in model system: measurement, modification, modelling," Hort. Sci., vol. 26, pp. 997-998, 1991.

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