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Journal : Journal of Tropical Crop Science

Water Balance in Oil Palm Plantation with Ridge Terrace and Nephrolepis biserrata as Cover Crop Ariyanti, Mira; Yahya, Sudirman; Murtilaksono, Kukuh; Suwarto, Suwarto; Siregar, Hasril H.
Journal of Tropical Crop Science Vol 3 No 2 (2016): Journal of Tropical Crop Science
Publisher : Department of Agronomy and Horticulture, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1114.492 KB) | DOI: 10.29244/jtcs.3.2.35-55

Abstract

The existence of oil palm plantations as a possible cause of drought in the surrounding areas in Indonesia is a critical issue. Therefore, information related to the effects of oil palm plantations on the surrounding environment in terms of soil water content (SWC) availability is needed. Soil and water conservation techniques in the form  of ridge terracing and cover crops,  such as Nephrolepis biserrata,  can be  expected to potentially improve soil water  reserves, especially in the dry-season, by accumulating water  in the rainy season.  This study aimed to study the effects of N. biserrata as cover crop, together with the potential effects of ridge terraces, on the water balance in mature oil palm plantations.  The research was conducted in mature oil palm plantations, Afdeling III block 375 (planted in 1996) and block 415 (planted in 2005), Rejosari Unit, PT Perkebunan Nusantara (PTPN) VII in Natar District, South Lampung Regency, Indonesia, from August 2014 to January 2015. The research was based on of setting up 15 m x 20 m experimental plots with the following treatments:  (i) without ridge terraces and without N. biserrata (G0T0); (ii) without ridge terraces but with N. biserrata (G0T1); (iii) with ridge terraces but without N. biserrata (G1T0); (iv) with ridge terraces and with N. biserrata (G1T1).   Hydrology parameter data were collected for each treatment plot; water balance was calculated using a water balance equation. The results showed that the use of the cover crop N. biserrata in combination with ridge terraces helped improving SWC reserves by approximately 71% and 12%, respectively.  The use of N. biserrata as a cover crop reduced the rate of water loss by percolation and run-off, by approximately 36% and 80%, respectively, in an area where the annual rainfall is above 2,400 mm per year.  The presence of N. biserrata shortened the period of SWC deficit by extending the period of a water surplus by 70 days when compared with ridge terracing alone (which reduced the period of SWC by 50 days).
The Roles of Asystasia gangetica (L.) T. Anderson and Ridge Terrace in Reducing Soil Erosion and Nutrient Losses in Oil Palm Plantation in South Lampung, Indonesia Asbur, Yenni; Yahya, Sudirman; Murtilaksono, Kukuh; Sudradjat, Sudradjat; Sutarta, Edy Sigit Sutarta Sigit
Journal of Tropical Crop Science Vol 3 No 2 (2016): Journal of Tropical Crop Science
Publisher : Department of Agronomy and Horticulture, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (215.122 KB) | DOI: 10.29244/jtcs.3.2.49-55

Abstract

Asystasia gangetica (L.) T. Anderson is a weed commonly found on oil palm plantations and can be used as cover crop for mature oil palm plantations due to its tolerance to shading. The use of cover crop is  a soil conservation technique to support sustainable availability of soil nutrients by reducing erosion and nutrients loss, particularly during the rainy seasons. This research aims to determine the roles of A. gangetica as cover crop for measures against erosion and nutrients loss in mature oil palm plantation. This research was conducted in oil palm plantation, Unit Rejosari, PT Perkebunan Nusantara (PTPN) VII, District of Natar, South Lampung Regency from August 2014 to April 2015. The research used split block design in randomized complete block design with two factors and six replications. The main plots were ridge terrace, namely with and without ridge terrace. The sub plots were cover crops, namely with and without cover crops A. gangetica. The results show that using A. gangetica as cover crops in mature oil palm plantations effectively minimized erosion and loss of organic C, N, P, and K by 95.7%, 93.4%, 96.0%, and 90.0 %, respectively. The use of cover crop became more effective when combined with ridge terrace and reduced erosion by 94.1% and loss of organic C, N, P and K by 99.1%, 99.2%, 90.0% and 98.5%, respectively.
Morphological Traits of Maluku Native Forest Clove (Syzygium aromaticum L. Merr & Perry) Mahulette, Asri Subkhan; Hariyadi, Hariyadi; Yahya, Sudirman; Wachjar, Ade; Alfian, Anggra
Journal of Tropical Crop Science Vol 6 No 02 (2019): Journal of Tropical Crop Science
Publisher : Department of Agronomy and Horticulture, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (784.544 KB) | DOI: 10.29244/jtcs.6.02.105-111

Abstract

A study was conducted to study the morphology of the forest cloves groups based on their sizes of their leaves, flowers, fruits and seeds, and to determine their potential yield and optimize their production system. The research was conducted for six months from January until June 2018 in Ambon, Maluku Province, Indonesia. The research used a random sampling technique to > 15-year-old trees in productive clove forest maintained by the local farmer in Ambon. The observation and recording was conducted at several stages of clover growth, namely bud sprouting, flower bud, blooming, perianths and anthers senescence, unripe green and ripe fruits. Different size groups of forest cloves have significant differences in the duration of flower and fruit formation. Forest cloves with large leaves, flowers, fruits and seeds had quicker ripening process than the othersize groups, but their fruits were longer to ripen. Flower from the medium size group had the shortest duration to develop its flower and form its fruit, whereas the smallest type took the longest time in fruit formation process but the duration of fruit ripening was similar to those from large morphology. Among the three different sizes of forest cloves in Maluku, the trees with large leaves, flowers, fruits and seeds group are the best to be commercially developed due to its earliest time to harvest and large flower sizes. Forest cloves are best harvested when the flowers are fully matured, indicated by one or two flower buds from one inflorescence have bloomed.
Plant Growth Performance of Top Grafted Young Cacao at Various Elevations in Indonesia Poleuleng, Andi Besse; Agusta, Herdhata; Yahya, Sudirman; Wachjar, Ade; Tjoa, Aiyen
Journal of Tropical Crop Science Vol 7 No 02 (2020): Journal of Tropical Crop Science
Publisher : Department of Agronomy and Horticulture, IPB University

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (781.91 KB) | DOI: 10.29244/jtcs.7.02.59-65

Abstract

The purpose of this study was to evaluate the plant growth performance of top grafted young cacao cultivated in various elevations. This research was conducted from January-August 2019 in South Sulawesi and Central Sulawesi. A total of 54 plants were taken randomly from 6 locations with 3 altitudes (<300, 300-600, >600 meter above sea level, as.). The results showed that there was not significant different of plant height, stem circle, crown circle, the number of primary branches, the number of flowers, the length of horizontal and vertical roots in response to different elevations. However, the height of primary stem and leaves number of cacao from <300 m asl was significantly greater than those from either 300-600 m asl or > 600 m asl. The largest crown portion of actual biomass was found in the branches, then followed by the leaves and stem. While the highest actual root biomass was found at 10-20 cm soil depth.