Hubungan Konsentrasi Hara Nitrogen, Fosfor, dan Kalium Daun dengan Produksi Buah Sebelumnya pada Tanaman Jeruk Pamelo

Penentuan status hara dengan analisis jaringan daun pada tanaman jeruk lebih tepat menggambarkan konsentrasi hara yang berhubungan dengan Perubahan produksi. Penelitian bertujuan menetapkan daun yang tepat untuk diagnosis status hara N, P, dan K pada tanaman jeruk pamelo. Survei dilaksanakan di lahan petani jeruk pamelo Pangkep pada Bulan Maret sampai Juni 2012 dengan ketinggian tempat 17–35 m dpl., dan analisis kimia di Laboratorium Tanah Balai Pengkajian Teknologi Pertanian Sulawesi Selatan. Penelitian menggunakan 150 pohon tanaman jeruk produktif yang berumur 5–8 tahun dengan pengelolaan yang relatif seragam. Pengambilan sampel daun ketiga-empat dan kelima-enam dari terminal dengan posisi cabang bagian atas dilakukan setelah panen. Analisis daun dilakukan dengan metode semi-mikro Kjeldahl untuk N, Spectrophotometer UV-VIS untuk P, dan Flamephotometer untuk K di Laboratorium Tanah BPTP Sulawesi Selatan. Hasil penelitian menunjukkan bahwa daun ketiga-empat memiliki korelasi terbaik dengan hasil serta mengandung konsentrasi hara N rendah (1,15–1,38%), P sedang (0,11–0,20%), dan K tinggi (2,31–2,94%). Konsentrasi N, P, dan K optimum dengan produksi relatif 85% masing-masing sebesar 1,77, 0,16, dan 1,67%. Hubungan konsentrasi hara dengan umur tanaman menunjukkan korelasi yang lemah tetapi rasio daun per buah yang tinggi menunjukkan konsentrasi hara N, P, dan K yang menurun, baik daun ketiga-empat maupun kelima-enam. Hasil penelitian ini dapat digunakan sebagai pedoman dalam menyusun rekomendasi pemupukan untuk tanaman jeruk pamelo

Discriminating Land Characteristics of Yield and Total Sugar Content Classes of Cilembu Sweet Potato (Ipomoea Batatas L.)

Cilembu sweet potato is a unique commodity with high demand market due to its sweet taste. The objectives of this study were to investigate the production performance of Cilembu sweet potatoes in term of production classes and critical limit and to determine discriminating land characteristics classes of yield and total sugar content. This study was conducted in Cilembu sweet potatoes production centers in West Java. Sweet potatoes tuber and soil samples were collected by purposive random sampling during harvest. Cilembu sweet potatoes production classes were defined by decreasing yields criteria in land evaluation. Critical limit production was the lowest yield and total sugar content of raw tuber which harvested in Cilembu village. Discriminating land characteristics were decided by discriminant analysis. Results showed that there was a significant different yield between typical and nontypical areas. Critical limit of yield and total sugar content were 10.5 t ha-1 and 2.32 %, respectively. The discriminating land characteristics of yield classes were soil properties (pH, CEC, P, Ca, Mg, ΔT), and monthly rainfall, whereas for total sugar content classes were effective soil depth, clay, sand and monthly rainfall. These variables are proposed as diagnostic criteria in Cilembu sweet potato land suitability criteria

Kebutuhan Nitrogen Tanaman Kedelai Pada Tanah Mineral Dan Mineral Bergambut Dengan Budi Daya Jenuh Air

The development of soybean in tidal land is faced with problems such as physical, chemical and biological soil properties, that includes high organic matter, high soil acidity, toxicity of Fe and Al, and deficiency of nutrients N, P , K, Ca and Mg. N content is high (> 0.51%) but with low availability. The research objective is to determine the dose and timing of N, P and K fertilizer application in accordance with the needs of soybean crops in order to have optimal growth and yield per unit of land in mineral and peaty mineral soil in tidal swamp land. The research was conducted in mineral and peaty mineral soil of tidal swamp land type C and B, District of Tanjung Lago, Banyuasin, South Sumatera from April to August 2014. The experiment was arranged following split plots design. Wilis and Tanggamus varieties as main plot, application time: 2, 3, 4 WAP, 2, 3, 4, 5 WAP, and 2, 3, 4, 5, 6 WAP as sub plots and fertilizer concentration: 7.5, 10, 12.5 dan 15.0 g/l water as subsub plots with spraying volume of 400 l/ha. Research results showed that mineral soil, dry weight of nodules and Wilis biomass increased with increasing frequency time of fertilizer application, while Tanggamus more fluctuated and declined at higher frequency of fertilizer application. Interaction of Wilis variety, time of fertilizer 2-6 WAP and concentration of 15 g N/I generated the highest yield of 3,5 ton/ha. In the peaty mineral soil, dry weight of nodules and biomass were not significantly different. Wilis productivity tends to decrease with increasing N fertilizer concentrations. Tanggamus productivity tends to increase with increasing N fertilizer concentration at all level of time of fertilizer application. Tanggamus tends to generate higher productivity of 3,2 ton/ha at a concentration of 15 g N/I with time of fertilizer application 2-4 MST. Application of low concentration N at higher frequency of fertilizer application or otherwise, was able to improve the productivity of soybeans in soil with high pyrite content

Penentuan Metode Terbaik Uji Kalium untuk Tanaman Tomat pada Tanah Inceptisols

Penelitian tentang studi analisis kalium tanah dan aplikasi pupuk kalium pada budidaya tomat pada tanah Inceptisols dilakukan di Kebun Percobaan dan Rumah Kaca di Cikabayan, Institut Pertanian Bogor, dari Bulan April hingga November 2011. Tujuan penelitian untuk mendapatkan metode ekstraksi kalium tanah yang terbaik guna menentukan dosis pupuk kalium pada budidaya tomat pada tanah Inceptisols. Penelitian menggunakan rancangan acak kelompok dengan perlakuan pemberian pupuk kalium pada beberapa tingkat dosis, yaitu 0, ¼, ½, ¾, dan 1X, dimana nilai X ialah 608,6 kg K O kg/ha dengan empat ulangan. Perlakuan pemupukan kalium diterapkan pada 3 bulan sebelum penanaman tomat. Analisis korelasi dilakukan antara kandungan K tanah dan pertumbuhan tanaman di dalam rumah kaca menggunakan media inkubasi berasal dari tanah setelah diberi perlakuan. Uji kalium tanah menggunakan lima metode ekstraksi, yaitu metode HCl 25%, NH422) OAc 1 M pH 7, Mehlich I, Truog, dan Morgan Vanema. Hasil penelitian menunjukkan perbedaan yang nyata antara pengaruh perlakuan pupuk K terhadap parameter tinggi tanaman, jumlah daun, dan diameter batang tomat. Bobot segar biomassa dan bobot kering tomat juga menunjukkan perbedaan pengaruh yang nyata antarperlakuan. Nilai korelasi tertinggi ditunjukkan pada metode pengekstrak Truog melalui parameter bobot kering dan basah relatif tanaman (r = 0,7). Dengan demikian, uji K tanah menggunakan metode Truog dapat digunakan sebagai metode ekstraksi yang paling tepat untuk menganalisis unsur hara kalium dalam rangka penyediaan rekomendasi pemupukan K pada budidaya tomat pada tanah Inceptisols

Geographical Classification of Java Tea (Orthosiphon Stamineus) From Java Island by FTIR Spectroscopy Combined with Canonical Variate Analysis

FTIR spectroscopy combined with canonical variate analysis was used for differentiation of java tea (Orthosiphon stamineus) according to their geographical origin. FTIR spectra of all java tea samples were acquired in the mid infrared region (wavenumber range 4000-400 cm-1). Preprocessing signal of FTIR spectra has been carried out prior to canonical variate analysis by standard normal variate. Combination of FTIR spectra in the region 1800-900 cm-1with canonical variate analysis has the power to differentiate java tea samples in terms of geographical origin. The developed method could be used for identification of geographical origin of java tea based on the samples used in this study

Impact of Brachiaria, Arbuscular Mycorrhiza, and Potassium Enriched Rice Straw Compost on Aluminium, Potassium and Stability of Acid Soil Aggregates

Acid soil is commonly grown with cassava, which in general, tolerate low soil fertility and aluminum (Al) toxicity. However, without any improvement efforts such soil will become worse. Intercropping cassava with Brachiaria decumbens (BD) which adapts to acid soil and tolerates low fertility soils as well as application of arbuscular mycorrhiza (AM) and organic matters are among the important efforts to rehabilitate this soil. The experiment was conducted to examine the impact of BD, AM, and potassium (K) enriched rice straw compost on exchangeable Al, available K, and stability of soil aggregates. Experiment was arranged in a completely randomized design with three factors and three replications. The first factor was BD as cassava intercropping, the second factor was AM, and the third factor was 2 t ha-1 rice straw compost enriched with 0 kg, 50 kg, 100 kg, and 200 kg KCl ha-1. Brick pots (1 m length x 1 m width x 0.45 m depth) filled with Kanhapludult soil was used for growing cassava in which row of BD was planted at 60 cm from cassava stem. K-enriched rice straw compost and AM (10 g per stem) were applied around cassava stem at 2 and 12 days after planting, respectively. BD was cut every 30 days and the cutting was returned to the soil. Soil exchangeable Al was analyzed at 0, 3, 6 and 9 months after planting (MAP), while Al and K contents as well as aggregate stability were measured at 6 MAP. The results showed that planting BD decreased 33% exchangeable Al, which means that the root exudates of this grass was effective in detoxifying Al3+. Treatment of BD and/or in combination with AM was effective in preserving K added to the soil, increasing total polysaccharides, and improving soil aggregate stability. This indicated that planting BD and applying AM and Kenriched rice straw compost improved acid soil fertility, and therefore can be recommended in cassava cultivation