Water Table Fluctuations Impact on Oil Palm Low Frond Desiccation Case Study in North Sumatra Peatland

Masalah tanaman kelapa sawit berupa kering pelepah bagian bawah (low frond desiccation/LFD) sering terjadi pada lahan gambut. Kejadian ini umumnya dikaitkan dengan kondisi fluktuasi muka air tanah gambut yang berpengaruh terhadap kelembaban tanah gambut dan ketersediaan serta serapan hara oleh tanaman. Penelitian ini bertujuan untuk mengkaji permasalahan LFD, faktor-faktor penyebab dan upaya pencegahan atau pemulihannya. Kajian LFD telah dilakukan di perkebunan kelapa sawit di lahan gambut daerah Labuhan Batu, Sumatera Utara. Pengamatan meliputi fluktuasi muka air tanah, kondisi kelembaban tanah, sifat kimia tanah, serapan hara daun, pertumbuhan dan produksi tanaman dilakukan pada blok tanaman normal dan blok tanaman mengalami LFD. Hasil penelitian menunjukkan bahwa terjadinya penurunan muka air tanah gambut secara drastis pada saat bulan kering berdampak terhadap penurunan kelembaban gambut, bahkan hingga tanah gambut mengering. Kondisi pengeringan gambut menyebabkan ketersediaan hara dalam tanah dan serapan hara menurun secara nyata, sehingga memicu terjadinya LFD. Serapan hara tanaman yang mengalami LFD berat menurun dengan kisaran penurunan sebesar 25 – 41% untuk hara makro dan 22 – 53% untuk serapan hara mikro. Kondisi LFD berat secara nyata menurunkan pertumbuhan dan produksi tanaman kelapa sawit. Penurunan produksi dapat mencapai 27% per tahun dibandingkan dengan tanaman normal. Tanaman mengalami LFD dapat berangsur pulih dengan penerapan water management yang efektif, kontinyu dan terkontrol melalui pengelolaan muka air tanah pada kisaran kedalaman 40-60 cm pada blok tanaman.Low frond desiccation (LFD) on oil palm plantation has been a major issue, which often occurs on peatland. LFD is generally associated with a fluctuation of peatland water table that affects peat soil moisture, nutrients availability, and nutrients uptake by oil palm. This research aims to study LFD comprehensively, including causative factors and efforts to prevent or recover the LFD occurrence. The LFD study was carried out on peat oil palm plantation at Labuhan Batu, North Sumatra. The observations included fluctuations of the water table, soil moisture, soil chemical properties, leaf nutrient uptake, growth and production between normal and oil palm which had LFD. Results showed that the drastic alleviate of peatland water table at dry months induce soil moisture depletion, even made the peat dried. Peat drying condition alters a significant deflation of nutrient availability and nutrient uptake in the soil, thereby triggered LFD occurrence. The nutrient uptake of the plant with severe LFD was decreased with a range of 25-41% for macronutrients and 22-53% for micronutrients. Severe LFD inhibited the plant growth and significantly decreased yield. The downturn of production could reach 27% per year compared to normal plants. Oil palm with LFD was able to gradually recover with effective, continuous, and controlled water management through groundwater lever in the range of 40-60 cm in the plantation area

Study of Density and Diversity of Soil Organisms Under Mature Oil Palm on Peatland

Penelitian ini dilaksanakan di lahan gambut pada Kebun Panai Jaya, PT Perkebunan Nusantara IV, Provinsi Sumatera Utara. Metode pengambilan sampel yang digunakan dengan cara Pit Fall Trap (untuk menjebak fauna permukaan tanah), Barlese Tullgren (untuk melihat fauna tanah yang aktif di dalam tanah) dan membuat lubang (untuk mendapatkan cacing). Metode yang mendapatkan fauna terbanyak yaitu dengan cara Pit Fall Trap. Fauna tanah berkorelasi positif terhadap suhu, kadar air dan respirasi tanah, sedangkan terhadap pH dan C/N berkorelasi negatif. Hasil penelitian menunjukkan, diantara fauna tanah pada plot penelitian, diketahui bahwa jumlah fauna yang paling mendominasi adalah semut rangrang dan diikuti oleh cacing tanah. Baik fauna tanah (makrofauna dan mesofauna) dan mikroorganisme eukariotik tanah (jamur dan bakteri) ditemukan paling banyak pada areal rumpukan kebun kelapa sawit.This study was conducted on peat land in Kebun Panai Jaya, PT Perkebunan Nusantara IV, North Sumatera province. The sampling method was Pit Fall Trap to trap ground level fauna, Barlese Tullgren to observe the active soil fauna in the soil, and making a soil hole to get the worms sample. The Pit Fall Trap could collect the highest number of the fauna. The soil fauna was positively correlated to temperature, soil moisture, and soil respiration, and it was negatively correlated to soil pH and C/ N ratio. This study showed that, among the soil fauna that found on the observed field, the dominated organisms are weaver ants and followed with earthworms. Both soil fauna (macro and mesofauna) and eukaryotic soil microorganism (fungi and bacteria) were highly found under the frond piles of oil palm plantation

Distribution of macronutrients (N, P, K, Mg) from single-nutrient and compound fertilizers application in oil palm seedlings (Elaeis guineensis Jacq.)

Nutrients availability and plant's ability to absorb nutrients are essential factors in supporting plant performance. There are two forms of fertilizer as a source of nutrients for oil palm, which are single-nutrient fertilizer (SNF) and briquette compound-nutrient fertilizer (BCNF). This study observed the concentration, uptake, distribution, and efficiency of macronutrients in plant organs of oil palm seedlings with two different fertilizer types. An experiment using oil palm seedlings was arranged in non-factorial complete randomized design (CRD) with three treatments, namely control, NPK in the form of briquettes, and single nutrient fertilizer consisting of urea, TSP, MOP, and kieserite with doses adjusting the composition of the slow-release BCNF (16-10-24-0.75) in three replications with a total of 27 seedlings. The results showed that the concentration, uptake, and distribution of nutrients between treatments and control were not significantly different. The order of nutrient uptake in leaves and stems of plants was N > K > Mg and P, while in roots was K > N > Mg > P. In BCNF and SNF treatments, the biomass accumulation in the stems, roots, and leaves were at percentage of 41 %, 30 %, and 29 %, while in the control, the biomass accumulation in the roots, stems, and leaves were at percentage of 39 %, 33 %, and 28 %, respectively. BCNF treatment had a greater efficiency indicated by a higher nutrient use efficiency (NUE) value compared to SNF or control.

Pengaruh Rock Phosphate Dan Dolomit Terhadap Distribusi Perakaran Tanaman Kelapa Sawit Pada Tanah Ultisols

Karakteristik morfologi akar tanaman kelapa sawit bervariasi pada berbagai jenis tanah yang disebabkan oleh perbedaan sifat fisik, kimia dan biologi tanah. Penelitian ini dilakukan untuk mengetahui pengaruh pemberian Rock phosphate dan dolomit terhadap karakteristik akar (perkembangan dan distribusi akar tanaman) pada tanah Ultisol. Penelitian dilaksanakan di Kebun Percobaan Aek Pancur milik Pusat Penelitian Kelapa Sawit, Tanjung Morawa, Sumatera Utara. Perlakuan yang dicobakan pada tanaman berumur 19 tahun dalam penelitian ini adalah K (kontrol); D (Dolomit dengan dosis 1 kg/pohon); RP (Rock Phosphate dengan dosis 1 kg/pohon); dan D+RP (Dolomit dan RP dengan dosis masing-masing 1 kg/pohon). Pengamatan dilakukan pada 1/6 bagian piringan dengan radius 0-4,5 m dari pangkal pohon dan kedalaman 0-40 cm. Distribusi perakaran tertinggi terdapat pada radius 0-1 m dari pangkal pohon. Akar primer lebih banyak ditemukan pada kedalaman 20-40 cm, sedangkan akar sekunder dan tersier lebih dominan pada kedalaman 0-20 cm. Aplikasi RP meningkatkan pH tanah sekaligus kandungan P, K, dan Mg pada perakaran. Total kerapatan akar (g/dm3) pada perlakuan RP berturut-turut 47%, 16%, dan 32% lebih tinggi dibandingkan perlakuan K, D, dan D+RP. Aplikasi RP pada penelitian ini dapat memperbaiki sifat kimia tanah, merangsang pertumbuhan akar, dan serapan hara tanaman

PEMANFAATAN BAKTERI ENDOFIT UNTUK MENINGKATKAN KERAGAAN BIBIT KELAPA SAWIT (Elaeis guineensis Jacq.)

Endophyte bacteria are microorganisms that live within plant tissue, harmless to the host plants, and usually contribute to plant health. Some of the endophytes are proved to be able to enhance plant growth by nitrogen fixation, phytohormones production such as indole acetic acid (IAA) and cytokines. This study aims to observe the influence of endophytic bacteria on the oil palm seedlings growth, nutrient absorption, and its potential on reducing the use of chemical fertilizer. The study was carried out in oil palm nursery at Aek Pancur substation since 3-monthsold until 9-monthsold. Treatments were arranged by using randomized completely block design (RCBD) with six treatments and repeated four times. The treatments are: (1) control; (2) 100% chemical fertilizer (standard); (3) 25% of urea dosage + inoculation of endophyte bacteria (B1N25); (4) 50% of urea dosage + inoculation of endophyte bacteria (B1N50); (5) 75% of urea dosage + inoculation of endophyte bacteria (B1N75); and (6) 100% of urea dosage + inoculation of endophyte bacteria (B1N100). The result showed that B1N75 was the best treatment indicated by higher relative agronomy effectiveness (RAE) up to 5.5% compared to standard.  On the other hand, its growth and biomass production were also equal to standard treatment. It means that application of endophyte bacteria could reduce the use of inorganic nitrogen fertilizer (Urea) up to 25%.Bakteri endofit merupakan mikroorganisme yang hidup di dalam jaringan tanaman, tidak berbahaya bagi tanaman inang, dan berasosiasi dengan tanaman untuk mendukung kesehatan tanaman. Peran bakteri endofit diantaranya adalah penambat nitrogen bebas udara, menghasilkan fitohormon yang dapat merangsang pertumbuhan tanaman seperti IAA dan sitokinin. Tujuan penelitian ini adalah mengetahui pengaruh inokulasi bakteri endofit dalam meningkatkan pertumbuhan bibit kelapa sawit, serapan hara, dan potensi pengurangan dosis urea. Penelitian ini dilaksanakan di pembibitan kelapa sawit Kebun Aek Pancur pada tahap main nursery sejak umur 3 bulan hingga 9 bulan. Perlakuan disusun menggunakan Rancangan Acak Kelompok (RAK) dengan enam perlakuan dan diulang sebanyak empat kali. Perlakuan terdiri dari (1) kontrol; (2) 100% pupuk standar; (3) 25% pupuk urea + inokulasi bakteri endofit (B1N25); (4) 50% pupuk urea + inokulasi bakteri endofit (B1N50); (5) 75% pupuk urea + inokulasi bakteri endofit (B1N75); dan (6) 100% pupuk urea + inokulasi bakteri endofit (B1N100). Hasil penelitian menunjukkan bahwa perlakuan B1N75 merupakan kombinasi perlakuan terbaik yang ditunjukkan dengan tingginya nilai efektif agronomi nisbi (EAN) 5,5% lebih tinggi dari standard dan memiliki performa keragaan serta produksi biomassa kering yang setara dengan 100% pemupukan nitrogen anorganik. Hal ini menunjukkan bahwa aplikasi bakteri endofit dalam penelitian ini mampu menurunkan penggunaan pupuk urea hingga 25%

Shortening harvest interval, reaping benefits? A study on harvest practices in oil palm smallholder farming systems in Indonesia

CONTEXT: Smallholders are responsible for a large share of global palm oil production. Yet, in Indonesia, the main palm oil producing country, smallholders’ yields remain low. Better management practices, including short harvest interval (HI, the number of days between two harvest rounds), could help to raise smallholder yields. However, at present, HI is long in smallholder fields and the drivers underlying this phenomenon are poorly understood. OBJECTIVE: We explored agronomic, socio-economic, and institutional factors that underlie harvesting practices in independent oil palm smallholder farming systems in Indonesia to assess scope for sustainable intensification through shorter HI and reduced harvest losses. METHODS: Combining methods from agronomy and anthropology, we followed harvest interval of 950 farmers in six representative locations across Indonesia via farmer diaries over a period of two years to establish a correlation with yield. To quantify this relationship, we conducted post-harvest field measurements, and to explain which underlying factors impact HI we did qualitative interviews and surveys. RESULTS AND CONCLUSIONS: The HI of smallholders in our study ranged from 10 to 39 days (average: 17-d). Half of the farmers followed long HI (\u3e16-d). Key factors impacting HI include annual fresh fruit bunch (FFB) yield, total palm area per farmer, trusted labor availability, plantation accessibility, and FFB price. Farmers responded to low yield by prolonging HI to increase labor productivity and optimize labor and transportation costs. SIGNIFICANCE: This study contributes to a better understanding of the relation between HI and yield in smallholder farming systems, by uncovering how socio-economic and institutional factors sometimes override agronomic considerations. Long HI can potentially lead to harvest loss from loose fruits and missed bunches, and reduce oil quality from overripe bunches. However, to obtain the benefits of shorter HI requires collective action and incentives along the supply chain to streamline the harvest and sale process

Keanekaragaman Flora Pada Berbagai Tingkat Kepadatan Tanah Di Hutan Pegunungan Taman Nasional Bromo Tengger Semeru (TNBTS)

Degradasi hutan merupakan faktor pembatas dari keberlanjutan ekosistemyang menyebabkan penurunan kualitas tanah, keanekaragaman hayati (flora dan fauna), dan fungsinya sebagai penyedia kebutuhan pokok dan jasa lingkungan. Keberhasilan upaya restorasi hutan yang akan dilakukan di TNBTS perlu dimonitor dan dievaluasi, untuk itu dibutuhkan beberapa informasi kondisi awal baik dari aspek tanah dan keanekaragaman flora sebelum dilakukan restorasi. Tujuan penelitian ini adalah mengkaji keanekaragaman flora pada berbagai stadia pertumbuhan di berbagai tingkat kepadatan tanah di kawasan hutan degradasi dibandingkan dengan kawasan hutan utuh di TNBTS, sebagai baseline dari upaya restorasi kawasan. Penelitian dilaksanakan di TNBTS, Pasuruan, Jawa Timur tepatnya pada dua resort pengelolaan yaitu RPTN Coban Trisula dan RPTN Pananjakan. Pengambilan data dilakukan dari bulan September 2016 hingga Desember 2016. Rancangan yang digunakan adalah rancangan tersarang (Nested Sampling Design) dengan 3 faktor sumber keragaman (SK) yaitu jenis hutan (hutan degradasi dan hutan utuh), kelerengan (Lereng tengah dan bawah) dan kedalaman tanah (0 - 10 cm; 10 - 20 cm; 20 - 30 cm). Pengamatan diulang 4 kali pada 4 Kawasan Konservasi yang berbeda (KK1, KK4, KK5A, dan KK5B), sehingga total pengukuran sebanyak 16 plot dengan 48 sampel tanah. Variabel yang diukur dari aspek flora yaitu indeks nilai penting (INP), indeks keanekaragaman jenis (H), indeks kekayaan jenis (R) dan indeks kemereataan jenis (E) dan dari aspek tanah yaitu berat isi, berat jenis, porositas, ketahanan penetrasi tanah, C-organik dan pH tanah. Berdasarkan hasil penelitian diketahui bahwa rata - rata indeks keanekaragaman jenis (H) di hutan degradasi lebih rendah jika dibandingkan dengan hutan utuh. Indeks H di hutan degradasi bervariasi tergantung dari stadia pertumbuhannya, untuk stadia semai tergolong „sedang‟(H‟=1,68), dan untuk stadia sapihan pancang dan pohontergolong „rendah‟ (H<1). Indeks H di hutan utuh tergolong „sedang‟ untuk stadia pertumbuhan semai, sapihan, pancang dan pohon (1<H<3). Di hutan degradasi, ada 3 jenis flora yang mendominasi yaituStyphellia javanica (stadia semai, INP=85%), pisang atau Musa paradisiaca (pancang, INP=193%), dan mentigen atau Vaccinium varingiaevolium (sapihan dan pohon, INP=147% dan 300%). Di hutan utuh didominasi oleh Eupatorium riparium (semai, INP=105%), Pilea melastomoides (sapihan, INP=146%),Pinanga coronata(pancang, INP=193%), dan Acacia decurrens (pohon, INP=287%).Tanah di kedua jenis hutan di TNBTS memiliki tingkat kepadatan yang rendah, BI tanah rata-rata 0,82 g cm-3, porositas tanah 63%, serta penetrasi tanah 0,10 MPa. Sekitar 20% penurunan jumlah jenis pohon di hutan TNBTS berhubungan dengan peningkatan penetrasi tanah (R=0,2101), namun hal tersebut tidak terjadi pada stadia semai, sapihan dan pancang

First things first: Widespread nutrient deficiencies limit yields in smallholder oil palm fields

CONTEXT: Indonesia is the most important oil palm producing country. Nearly 40% of planted area is managed by smallholders, with yields well below the potential. Efforts to increase productivity have focused on the source of planting material, with little attention paid to plant nutrition. OBJECTIVE: To assess the degree to which current productivity in smallholder oil palm fields is limited by nutrients in scenarios with distinct sources of planting material. METHODS: We collected detailed data on leaf nutrient concentration from 30 fields to derive minimum sampling size needed to diagnose nutrient status. Subsequently, we collected data on yield and palm type from 973 smallholder fields to assess the importance of nutrient status and planting material in the determination of yield. RESULTS AND CONCLUSIONS: Potassium (K) deficiency was widespread (88% of fields) and often severe. Nearly two thirds of fields were also deficient for nitrogen (N) and boron (B), half were phosphorous (P) deficient, and one third were magnesium (Mg) deficient. Nutrient imbalances, especially between K and N, were also common. Fields with sufficient N, P, and K levels yielded 47% more (equivalent to 1.2 t oil ha-1) than deficient fields across the entire range of planting materials. We conclude that improved plant nutrition increases fresh fruit yields in smallholder fields irrespective of the source of planting material. The advantage of certified planting material is reflected in the higher oil extraction rates. SIGNIFICANCE: Increased smallholder oil palm yields on existing plantations through improved plant nutrition offers the opportunity to improve smallholder profits and livelihoods, whilst at the same time increasing total oil production without bringing new areas into cultivation