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PENTINGNYA HARA K DAN PUPUK BAGI TANAMAN TEBU Bahan kajian MK Pupuk dan Pemupukan Diabstraksikan oleh Prof Dr Ir Soemarno MS Jur Tanah FP UB Oktober 2011. FUNGSI K BAGI TANAMAN Kalium terlibat dalam banyak aspek fisiologis tanaman : Mengaktivkan berbagai jenis ensim
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PENTINGNYA HARA K DAN PUPUK BAGI TANAMAN TEBU Bahan kajian MK Pupuk dan Pemupukan Diabstraksikan oleh Prof Dr Ir Soemarno MS Jur Tanah FP UB Oktober 2011
FUNGSI K BAGI TANAMAN Kaliumterlibatdalambanyakaspekfisiologistanaman: Mengaktivkanberbagaijenisensim Membantufotosintesis Mendorong status energi yang tinggi Mempertahankanturgorsel Meregulasimembukanya stomata daun Membantupenyerapan air Meregulasipengangkutanharadalamtanaman Membantupengangkutandanpenyimpanankarbohidrat Membantupenyerapan N dansintesis protein Membantusintesispatidalamdaun
ASAM HUMAT + PUPUK NPK MEMPERBAIKI KETERSEDIAAN HARA TANAH Aplikasi asam humat bersama dengan pupuk NPK meningkatkan ketersediaan unsur hara dalam tanah (Vertisol dan Alfisol) bagi tanaman. Perlakuan aplikasi terbaiki adalah 10 kg ha-1 asam humat (soil application) + 0.1% asam humat semprotan daun (dua kali) + 0.3% asam humat + 100% NPK dosis rekomendasi. Perlakuan lain yang sama baiknya adalah aplikasi asam humat 20 kg ha-1 HA (soil application) + 100% NPK dosis rekomendasi. Sumber: Journal Acta Agronomica Hungarica Volume 52, Number 3 / November 2004
KALIUM & KUALITAS TEBU KALIUM merupakankation yang banyakterakumulasidalamcairanseltanamantebu. Tanamantebu yang sehatbiasanyamengandungkaliumlebihdari 200 kg K/ha. Kalausuplaikaliumtidakmencukupi, indikator yang paling terpengaruhadalahpanjang-batang yang dapatdigiling, danjumlahbatanganakan. Kaliumjugaberfungsisebagaiaktivatorensim, K sangatpentingdalamprosessintesisdantranslokasisukrosedaridaunkejaringansimpanansukrosedibatangtebu. Respontanamantebuterhadappupuk K sangattergantungpadaketersediaan K-tanah, respon yang signifikanhanyaterjadipadatanah-tanah yang kandungan K-tersedianyarendah Biasanyatanamanteburesponterhadappupuk K denganpeningkatanhasiltebu, tanpapeningkatankadarsukrose. Serapan K yang berlebihanolehtanamantebudapat “menekanataumembatasi” recovery sukroseselamapenggilingan. Sehinggapemupukan K harusdibatasiuntukmencukupiproduksi optimum danuntukmembanturegulasikemasakan, sehinggahasilgulamaksimumdapatdiperolehdaribatangtebu yang dapatdigiling.
KALIUM & KUALITAS TEBU KALIUM merupakankation yang banyakterakumulasidalamcairanseltanamantebu. Tanamantebu yang sehatbiasanyamengandungkaliumlebihdari 200 kg K/ha. Kalausuplaikaliumtidakmencukupi, indikator yang paling terpengaruhadalahpanjang-batang yang dapatdigiling, danjumlahbatanganakan. Kaliumjugaberfungsisebagaiaktivatorensim, K sangatpentingdalamprosessintesisdantranslokasisukrosedaridaunkejaringansimpanansukrosedibatangtebu. Respontanamantebuterhadappupuk K sangattergantungpadaketersediaan K-tanah, respon yang signifikanhanyaterjadipadatanah-tanah yang kandungan K-tersedianyarendah Biasanyatanamanteburesponterhadappupuk K denganpeningkatanhasiltebu, tanpapeningkatankadarsukrose. Serapan K yang berlebihanolehtanamantebudapat “menekanataumembatasi” recovery sukroseselamapenggilingan. Sehinggapemupukan K harusdibatasiuntukmencukupiproduksi optimum danuntukmembanturegulasikemasakan, sehinggahasilgulamaksimumdapatdiperolehdaribatangtebu yang dapatdigiling.
K dan KUALITAS TEBU Kadar sukroseniratebusangatditentukanolehvarietasdankondisiiklim, pemupukanhanyasalahsatufaktor yang ikutmempengaruhirndemen. Biasanyahasilpenelitianpemupukankaliummenunjukkanbahwaresponhasiltebuterhadappupuk K tidakdiikutidenganpeningkatansukrosedalamtebu. HasilpenelitiandiAfrikaselatan, peningkatandosispupuk K yang tidakmendatangkanresponhasiltebu, ternyatahanyasedikitberpengaruhpadakualitastebu. Aplikasipupukkaliumsecarabertahapdua kali (50% saattanamdan 50% padaakhirmusim) memberikanhasiltebudanjumlahbatangtebu yang maksimum, sedangkankualitasniratidakterpengaruhi.
KALIUM DAN RENDEMEN TEBU K has a tendency to increase sucrose solubility during sugar processing, thus maintaining a certain amount of sucrose in solution, one K+ tying up one molecule of sucrose. A significant depression in sucrose concentration of cane following an application of 183 kg K ha–1 in South Africa. Chapman (1980) observed in long term trials in Australia that 196 kg K ha–1 slightly decreased sucrose content in cane when compared to the no K treatment. A more vivid example of K lowering sucrose recovery is provided by Korndorfer (1990) who observed that vinasse (distillery slops) when applied at 120 m3 ha–1 to a dark red dystrophic latosol in Brazil increased cane yield from 98 to 127 t ha–1 but decreased recoverable sucrose concentration in cane from 15.0 to 13.1%.
REKOMENDASI PUPUK K TANAMAN TEBU Sumber: SASRI-FAS, 2002.
PUPUK K TANAMAN TEBU Aplikasipupuk K dapatmeningkatkanhasiltebudanrendemennyakalautanahnyamengandungkaliumkurangdari 102 ppm. Dosis optimum pupuk K sekitar 140 kg/ha dapatmeningkatkanhasilgulasekitar 2.8 t/ha. Aplikasipupuk N dan K mampumeningkatkanhasilgulapadalahantebu yang miskinkalium. Kaliummemperbaikimetabolisme N tanamandankaliummenjadifaktorpembatasuntukproduksiguladilahanini. Tingkat kritisuntukrespon K padatanah-tanahiniadalahsekitar 102 ppm K-terekstraks. Tanah-tanahdnegankandungan K-ekstrakslebihdari 140 ppmtidakresponterhadappupukkalium. Sumber: Better Crops International, Vol. 14, No. 1, May 2000
WAKTU APLIKASI PUPUK K Waktuaplikasipupuk K berpengaruhterhadaphasiltebudan status nutrisi K tanamantebu. Penangguhanseluruhatauseparuhdosispupukrekomendasi 150 Kg K/ha hinggabersamaandengansaatpuncakpertumbuhantanamantebuternyatatidakberpengaruhpadahasiltebudan status haratanaman. Di daerahdengancurahhujanlebihdari 2000 mm per tahun, sebaliknyapemupukankaliumdilakukansetiaptahunpadasaattanam (awalmusim). Sumber: Nutrient Cycling in Agroecosystems Volume 20, Number 3, 153-158.
NilaiKritis K-tanah Nilaikritis K-tersediapadatanahberpasir 46.2 mg/kg. Nilaikritis K-tersediatanahberlempung 51.4mg/kg. Nilaikritis K-tersediapadatanahliat 60 mg/kg.
Klasifikasi ketersediaan kalium tanah bagi tanaman tebu Texture Soil available) Increases yield K(mg/kg kg per K2O kg ( %) Sand Low <46 113 91 China 46- 90 >18 13.3 It is high> 90 - – Loam Low <52 109.2 >15 China 52- 110 88 10 It is high > 110 - – Clay Low <60 139.7 >10 China 60- 120 67.2 7.5 It is high > 120 < 8 < 5
SERAPAN KALIUM TANAMAN TEBU Setiap hektar tanaman tebu menyerap kalium sekitar 100.91-315.28 kg K2O. 2. Hasil tebu berkorelasi positif dengan serapan kalium (r = 0.979**) 3. Hasil tebu (y) berhubungan secara linear dengan serapan kalium (x) : y = 31687.1 + 246.0 x.
Aplikasi pupuk K pada tebu Tanaman tebu menyuerap kalium dalam jumlah yang lebih banyak dibandingkan dengan N dan P Penyerapan K paling banyak terjadi pada fase pertumbuhan awal dan pertengahan vegetatif.
KALIUM TANAMAN TEBU Pengelolaan Kalium Tanaman Tebu harus memperhatikan hal-hal berikut: Nilai kritis K-tersedia dalam tanah, tanah pasir 46.2 mg/kg. Tanah lempung 51.4mg/kg; Tanah liat 60 mg/kg . Setiap hektar tanaman tebu menyerap sekitar 100.91-315.28 kg K2O atau setiap ton tebu menyerap K2O 1.98 - 2.71 kg. Efisiensi pemupukan kalium tanaman tebu 29.4 - 40.6%. Serapan kalium tanaman tebu pada berbagai fase pertumbuhan: Fase kecambah 4.2%, Fase pembentukan anakan 13.7%, Fase vegetatif awal 32.8%, Fase pertumbuhan lanjut 41.2%, Fase pemasakan 8.1%. Kecepatan penyerapan kalium pada fase pertumbuhan awal adalah 160 g/day/hm2 pda tanaman yang dipupuk NPK. Kecepatan penyerapan kalium pada fase pertumbuhan vegetatif sebesar 2180 g/day/hm2. Intensitas penyerapan kalium tanaman tebu dapat menurun menjadi 250 g/day/hm2 pada fase pemasakan.
The potassium cycle in the soil-plant-animal system (from SYERS, 1998)
Effect of K on sucrose content and sugar yield of cane in India (IPI on-farm trials, 2001)
Model Siklus Calvin yang disederhadnakan. Triose phosphates (TP) can either be exported to the cytosol for sucrose synthesis or stay in the chloroplast for starch synthesis; however, the bulk of TP is used for ribulose-1,5-bisphosphate (RuBP) regeneration. Sintesis sukose dalam cytosol is tergantung pada impor Pi oleh khloroplas.
MEKANISME PENYERAPAN K+ OLEH AKAR Proses pertukaran kation antara akar tanaman dengan aprtikel tanah http://click4biology.info/c4b/9/plant9.2.htm
PENYERAPAN KATION K+ Membran plasma sel-tanaman dapat menyerap ion dengan dua cara berbeda yang memerlukan energi: Metode tidak langsung, dimana pompa proton (hydrogen pumps) menciptakan gradien elektrokimia Metode langsung, dimana membran sel secara aktif mengangkut ion tertentu. Proses tidak langsung: Pompa Proton (hydrogen) dalam membran plasma memompa ke luar H+ dan selanjutnya hal ini akan mempunyai dampak ikuran seperti gambar berikut. http://click4biology.info/c4b/9/plant9.2.htm
Penyerapan ion : METODE LANGSUNG Ion K+ yang bebas dan ada dalam larutan tanah diambil secara aktif oleh pompa membran transport aktif. Pompa membran ini bersifat spesifik untuk setiap jenis kation. http://click4biology.info/c4b/9/plant9.2.htm
. Fotoreduksi (reduksi FeIII cyanide) dan foto-fosforilasi dalam kloroplast merupakan fungsi dari konsnetrasi K+ (K1 = suplai K suboptimum, K2 = suplai K optimum)
Peranan K dalam sistem transpor nitrat dan malate dalam tanaman. PEP= phosphoenol pyruvate (Marschner, 1995).
KALIUM MEMPERBAIKI RENDEMEN TEBU AplikasikaliummeningkatkanhasiltebudanrendemenpadatanahAndisolsdanEntisols, kalaukandungan K-tanahkurangdari 102 ppm. Dosis optimum K2O sebesar 140 kg/ha dapatemningkatkanhasilgulasebesar 2.8 t/ha. Peningkatanhasilgula yang konsistenterjadikalaupupukNkdiaplikasikanpadaAndisol yang miskinkalium. Hal iniberarti K dapatmemperbaikipenggunaan N olehtanamandapatmenjadifaktorpembatasuntukproduksigula. Tingkat kritis K-tanahadalahsekitar 102 ppm. Tanah-tanahdengan K-tanahlebihdari 140 ppmternyatatidakresponterhadappemupukan K. Sumber: Better Crops International Vol. 14, No. 1, May 2000
PUPUK K DAN P RENDEMEN TEBU Aplikasi pupuk K dan P memperbaiki kualitas dan hasil tanaman tebu. Dosis yang diaplikasikan adalah potassium (0; 86 dan 172 kg/ha K2O) dan phosphorous (TSP) (0; 64.5 dan 129 kg/ha P2O5). Pupuk K dan P tidak meningkatkan kadar serat tebu; sedangkan kadar air tanaman dipengaruhi oleh pupuk K. Pupuk P meningkatkan kadar gula (polarization %) dan kemurnian nira tebu (°/u). Persen brix tebu menurun pada akhir musim sebagai respon thd pupuk P, sedangkan ratoon hanya sedikit terpengaruh. Sedangkan pupuk K tidak berpengaruh terhadap persen Brix, baik tebu-tanaman maupun ratoon. Sumber: Journal of Applied Sciences 7 (16): 2345-2350, 2007
APLIKASI PUPUK P & K TANAMAN TEBU Aplikasipupuk P dan K berpengaruhterhadaphasiltanamantebu. Dosisaplikasinyaadalah (0, 72, dan 144 kg K/ha) dan (0, 29 dan 58 kg P/ha). Aplikasikaliummeningkatkan diameter batang, tinggibatang, hasiltebudanhasilgula. Aplikasipupuk P meningkatkantinggibatang, jumlahruas, hasilgula. Aplikasi P padaratoonmeningkatkanhasiltebudanhasilgula. Kandungan K-tersediadan P-tersediadalamtanahmenurunsetelahpanentebu. Sumber: Journal of Plant Nutrition . Volume 27, Issue 4, 2004, Pages 663 - 699
DEFISIENSI K TEBU menghambattranslokasifotosintat Defisiensi K menghambattranslokasifotosintatdaridaunkebagiantanamanlainnya. Translokasiiniterhambatdalamhelaidaun yang tidakmenunjukkangejaladefisiensi K dantidakadagejalapenurunanfotosintesis. Padakondisidefisiensi yang parah, lajufotosintesisdankonversihasilfotosintesismenjadihasilakhirakanterhambat. Lajurespirasidaun yang defisien K jugamengalamipeningkatan. Penurunantranslokasi yang disebabkanolehdefisiensi K dianggapsebagaiefekutamaakibatdarimunculnyagejaladefisinesikalium..
Nilai kritis K-tanah yang ditetapkan melalui hasil kajian SASRI-FAS Rekomendasi dosis pupuk K : SASRI-FAS, 2002.
Hubunganantarakandungan K-tukardalamtanahdenganhasilrelatiftebu (sumber: Farina et al., 1992). Farina, M.P.W., Channon, P., Thibaud, G.R. & Phipson, J.D. 1992. Soil and plant potassium optima for maize on a kaolinitic clay soil. S. Afr. J. Plant Soil 9, pp. 193 - 200.
TOTAL KALIUM DALAM TANAH •The soil of the total potassium was≤5 g/kg and accounts for 88.5%, •the total potassium was between 5 to 10 g/kg and accounts for 9.6%, •the content of the total potassium was between 10 to 15 g/kg and accounts for 1.9%, •there is no soil that content of the total potassium is greater than 15 g/kg. Potassium nutrient management for planting area of the sugarcane Hongwei Tan Liuqiang Zhou Rulin Xie Meifu Huang (soil and fertilizer institute, Academy of Agricultural Sciences of Guangxi, 530007)
KALIUM LAMBAT TERSEDIA DALAM TANAH The slow release available potassium was ≤30 mg/kg and accounts for 25%, the slow release available potassium was between 30 to 60 mg/kg and accounts for 50%, the slow release available potassium was between 60 to 120 mg/kg and accounts for 17.3%, the slow release available potassium was between 120 to 180 mg/kg and accounts for 5.8%, the slow release available potassium was between 180 to 240 mg/kg and accounts for 1.9%, there is no soil that slow release available potassium of soil is greater than 240 mg/kg. Potassium nutrient management for planting area of the sugarcane Hongwei Tan Liuqiang Zhou Rulin Xie Meifu Huang (soil and fertilizer institute, Academy of Agricultural Sciences of Guangxi, 530007)
Klasifikasi kalium tersedia dalam tanah untuk produksi tebu Potassium nutrient management for planting area of the sugarcane Hongwei Tan Liuqiang Zhou Rulin Xie Meifu Huang (soil and fertilizer institute, Academy of Agricultural Sciences of Guangxi, 530007)
JUMLAH KALIUM YANG DISERAP TANAMAN TEBU Setiap satu hektar tanaman tebu menyerap K2O sebanyak 100.91 - 315.28 kg. The result of the field experiments is indicated, the sugarcane yield with potassium absorbed amount of sugarcane present positive correlation, coefficient correlation r=0.979**, Whether reach remarkable level extremely, sugarcane yield (y) relational expression with function of sugarcane who absorbed potassium (x):y=31687.1+ 246.0x. Potassium nutrient management for planting area of the sugarcane Hongwei Tan Liuqiang Zhou Rulin Xie Meifu Huang (soil and fertilizer institute, Academy of Agricultural Sciences of Guangxi, 530007)
Change of potassium absorbing intensity for sugarcane in different period ofduration Potassium nutrient management for planting area of the sugarcane Hongwei Tan Liuqiang Zhou Rulin Xie Meifu Huang (soil and fertilizer institute, Academy of Agricultural Sciences of Guangxi, 530007)
Change of N, P and K nutrient content for sugarcane in different growth stage (CK) Potassium nutrient management for planting area of the sugarcane Hongwei Tan Liuqiang Zhou Rulin Xie Meifu Huang (soil and fertilizer institute, Academy of Agricultural Sciences of Guangxi, 530007)
KALIUM BAGI TEBU Potassium (K) is the most abundant cation accumulating in the cell sap of sugarcane plant. A healthy sugarcane crop indeed contains generally more than 200 kg K ha–1 in its aerial parts. Though in the absence of an adequate K supply, leaf area, tiller density and number of green leaves per mother shoot may not be affected, the height of millable stalks at harvest and to a lesser degree the number of stalks may be impaired. By acting mainly as an enzyme activator in plant metabolism, K is fundamental to the synthesis and translocation of sucrose from the leaves to the storage tissues in stalks. It also plays a significant role in controlling the hydration and osmotic concentration within the stomata guard cells. The Effects of Potassium on Growth, Development, Yield and Quality of Sugarcane K.F. NG KEE KWONG Sugar Industry Research Institute, Réduit, Mauritius
RESPON TEBU TERHADAP KALIUM Responses of sugarcane to K fertilization reflect to a large extent the available K status of soil, significant responses being obtained only in soils low in available K. Evaluating the response of sugarcane to K fertilization must also take into account the semi-perennial nature of sugarcane plant. In this context as sugarcane is able to mine the soil of its K reserves, responses to K fertilizers are frequently not observed in plant cane and often even in first and second ratoons. The Effects of Potassium on Growth, Development, Yield and Quality of Sugarcane K.F. NG KEE KWONG Sugar Industry Research Institute, Réduit, Mauritius
RESPON TEBU TERHADAP KALIUM The importance of a balanced nutrition particularly between nitrogen (N) and K in the attainment of the maximum yield should also not be overlooked. In general sugarcane responds to K fertilizers by an increase in cane yield without any change in sucrose concentration in the cane. As an excessive uptake of K by the sugarcane depresses the recovery of sucrose during milling, K fertilization of sugarcane must be kept just adequate to produce an optimum yield and to help regulate maturity so that maximum sugar is recovered from the millable canes. The Effects of Potassium on Growth, Development, Yield and Quality of Sugarcane K.F. NG KEE KWONG Sugar Industry Research Institute, Réduit, Mauritius
TANAMAN TEBU MEMERLUKAN BANYAK KALIUM Sugarcane is capable of rapidly depleting soil of nutrients, particularly potassium. Under South African conditions, for instance, the aerial parts of an adequately fertilized 12 monthold rainfed plant cane crop has been reported to contain 214 kg K ha–1 Wood, R.A. 1990. The roles of nitrogen, phosphorus and potassium in the production of sugarcane in South Africa. Fertilizer Research 26: 87-98. The Effects of Potassium on Growth, Development, Yield and Quality of Sugarcane K.F. NG KEE KWONG Sugar Industry Research Institute, Réduit, Mauritius
TANAMAN TEBU MEMERLUKAN BANYAK KALIUM Under irrigation, a cane crop of similar age and variety may remove as much as 790 kg K ha–1. In the Histosols of Florida, an average of 343 kg K ha–1 was removed from the field at harvest of the sugarcane Coale, F.J., Sanchez, C.A., Izuno, F.T. and Bottcher, A.B. 1993. Nutrient accumulation and removal by sugarcane grown on Everglades Histosols. Agronomy Journal 85: 310-315. The Effects of Potassium on Growth, Development, Yield and Quality of Sugarcane K.F. NG KEE KWONG Sugar Industry Research Institute, Réduit, Mauritius
TANAMAN TEBU MEMERLUKAN BANYAK KALIUM In Australia the average kg K ha–1 in the aboveground biomass of a crop of 84 tonnes cane ha–1 was 198 kg K ha–1 Chapman, L.S. 1996. Australian sugar industry by-products recycle plant nutrients. In : Downstream effects of land use (Ed. Hunter, H.M., Eyles, A.G. and Rayment, G.E.). Queensland Department of National Resources, Queensland, Australia. The Effects of Potassium on Growth, Development, Yield and Quality of Sugarcane K.F. NG KEE KWONG Sugar Industry Research Institute, Réduit, Mauritius
Dry matter and K accumulation rates, tillers and leaf area formation in rainfed ratoon cane harvested in August and fertilized in September in Mauritius The Effects of Potassium on Growth, Development, Yield and Quality of Sugarcane K.F. NG KEE KWONG Sugar Industry Research Institute, Réduit, Mauritius
Effect of K manuring on height, stalk population and yields of sugarcane (Donaldson et al., 1980) Donaldson, R.A., Meyer, J.H. and Wood, R.A. 1990. Response to potassium by sugarcane grown on base saturated clay soils in the Eastern Transvaal lowland. Proceedings of the Annual Congress of South African Sugar Technologists Association 64: 17-21. The Effects of Potassium on Growth, Development, Yield and Quality of Sugarcane K.F. NG KEE KWONG Sugar Industry Research Institute, Réduit, Mauritius
KALIUM DAN RENDEMEN TEBU If the K supply is inadequate, hydrolytic activity of invertase may be intensified resulting in cane with high reducing sugars but low sucrose level Filho, J.O. 1985. Potassium nutrition of sugarcane. In : Potassium in agriculture. (Ed. Munson, R.D.). American Society of Agronomy, Crop Science Society of America, Soil Science Society of America, Madison. pp 1045-1062. The Effects of Potassium on Growth, Development, Yield and Quality of Sugarcane K.F. NG KEE KWONG Sugar Industry Research Institute, Réduit, Mauritius
DEFISIENSI KALIUM TANAMAN TEBU Since K is a highly mobile nutrient in the plant, early symptoms of K deficiency are first seen in the older leaves. Leaf borders and tips will show yellow-orange chlorosis with numerous chlorotic spots that subsequently coalesce into brownish chlorotic blotches. This reduces the green leaf area in which photosynthesis takes place thereby depressing the growth of sugarcane. As rate of photosynthesis decreases with increasing severity of K deficiency, plant growth is retarded, internodes become shorter and the stalks themselves are shorter and smaller in diameter than those of well-fertilized sugarcane plants. The Effects of Potassium on Growth, Development, Yield and Quality of Sugarcane K.F. NG KEE KWONG Sugar Industry Research Institute, Réduit, Mauritius
DEFISIENSI k DAN FOTOSINTESIS TEBU Working with varieties H37-1933 and H50- 7209 (Hartt and Burr, 1967) found that K deficiency suppressed photosynthesis when the foliar K concentration fell to about 0.40 K% dry matter. Hartt, C.E and G.O Burr. 1967. Factors affecting photosynthesis in sugarcane. Proceedings of the Congress of the International Society of Sugar Cane Technologists 12: 510-609. The Effects of Potassium on Growth, Development, Yield and Quality of Sugarcane K.F. NG KEE KWONG Sugar Industry Research Institute, Réduit, Mauritius
RESPON PUPUK KALIUM Lakholine et al. (1979) showed in a 3- year study under Vidarbha conditions in India that there was no response to K applied at 50 -100 kg K ha–1. Prasad et al. (1996), found in a sandy loam calcareous soil of North Bihar that cane yield was increased from 50 t ha–1 without K fertilization to 74.5 t ha–1 with only 60 kg K ha–1. Prasad, R., Prasad, U.S. and Sakal, R. 1996. Effect of potassium and sulfur on yield and quality of sugar cane grown in calcareous soils. Journal of Potassium Research 12: 29-38. The Effects of Potassium on Growth, Development, Yield and Quality of Sugarcane K.F. NG KEE KWONG Sugar Industry Research Institute, Réduit, Mauritius
Response of sugarcane to increasing rates of K in soils of Mauritius with low, medium and high available K as extracted in 0.1M H2SO4 The Effects of Potassium on Growth, Development, Yield and Quality of Sugarcane K.F. NG KEE KWONG Sugar Industry Research Institute, Réduit, Mauritius
Response of sugarcane found from 1990 to 1993 at a site in Mauritius (Sans Souci) with only 0.16 cmol exchangeable K kg–1 The Effects of Potassium on Growth, Development, Yield and Quality of Sugarcane K.F. NG KEE KWONG Sugar Industry Research Institute, Réduit, Mauritius
Sugarcane first ratoon response to K as affected by (A) P rates and (B) K rates in plant cane (Rodella, 1990) Rodella, A.A. 1990. Nutrient response relationships between ratoon and plant crops in sugar cane. Sugar Cane 1: 3-7.