8342937091

Pertanika 14(1). 31 -35 (1991)

Copper and Limę Interaction on the Growth of Com on Tropical Peat

SYED OMAR S.R., M.H. AHMAD HUSNI. A.R. ANUAR AND M.A. ROZILAN

Department ofSoil Science Facu Ity of A picu Itu re Uniycrsili Pertanian Malaysia 43400 UPM Serdang, Se la ngo r Da ru l Eh san, Malaysia.

Key words: copper sulphate, dolomitic limestone, peat, corn, dry matter weight.

ABSTRAK

Kuprum telah dikenalpaślisebagai salah satu mikronutńen yang pali ngterhad dałam kebanyakan tanamanyang ditanampada tanah gambut tropika. Kajian im dijalankan untuk menentukan keson interakńdianlara kuprum dan kapurkeatas tumbesaran jagungmanis (Zea mays L.var. 1'hai Super sweet). Sa mpel tanah gambut yang belum terganggu telahd/amhil padakedalum 0-20 cm. Sampel tanah yang lembab digaul rata dan dimasukkan ke dałampasu plastik dan dirawnt dengan 5 kadarkuprum sulfat (bersamaan kadar 0, 5, 10, I 5 dan 20 kg Cu ha ^!) dan 4 kadar kapur (dolomitic limeslone) (0,2,4 dan lOt kapurha" ¹). Penggunaan kupru m pada kadar 5 kg Cu luf ¹ dan 41 kapur ha~' membeńkan hasil bera t kering yang optimum. Pengambilan kuprum olch jagungadalah rendah pada semua kadar kapur a pabi la penambahan kuprum melebihi kadar lókgCu ha'¹. Kajian ini menunjukkan bahawa tanah gambut yang men gandungi kurangdań 8. 7 fig Cug"¹ yang diekstrak oleh DTPA memerlukan pe m bajda n kuprum. pil tanah gambut sekurang-kurangnya 4.40 membeńkan pengumpulan hasil berat keringjagu ngyang maksim u m. Kajian ini mencadangkan bahawa tanah gambut tropika memerlukan pengapuran dan pembajaan kuprum, dan input-input ini membeńkan kesan sinergistik ke atas tu mbesaran jagungmanis.

ABSTRACT

Copper has been recognized as one oj the most limiting micronutrients in many cropsgrown on tropical peat. iluś study was conducted to detemii ne the ejjects of copper and limę interaction on the growth of sweet corn (Zea mays L.var. 1'hai Supersweel). An undisturbedpeatsample was taken at a depth of 0-20cm. Themoistpeat was then thoroughly mixed and placed in plasticpots which were treated with 5 rat es of copper sulphate (at equivalent rates ofO, 5, 10, 15 and 20 kg Cu ha~¹) a nd 4 rates of dolomitic li mestone (0,2,4 and 101 li me ha ¹). A pplication of copper at the ratę of 5 kg Cu ha~^l and 41 CMI. ha ¹ giues optimum chy matter yield. Addition of copper at a rateof morethan 16 kg Cu ha-1 reduces the uptake of copper łty corn at alt rates oj limę. The results also indicate that peat soil eon taining less (han S. 7/Jgg~¹ I)TPA extractable copper requires copperfertilization. The minimu m peat soilpU thatgives the maxium accumulated corn dry matter yield is 4.40. This study suggests that tropical peat requires li mi ng and copperfertilization and that theseinputs have synergist i c ejjects on the growth of sweet corn.

INTRODUCTION

About 32 million ha in the rain forest regions of Southeast Asia, South America and Africa are covered by peat (Driessen and Sudewo 1977. MaIaysi a, accoun ts for morę than 2.3 m i 11ions ha of peat coyering 7% oftotal land area (Joseph et ai 1974). Copper (Cu) has been recognisedasoneof the most important limiting micronutrients in many cropsgrown on peat. AvailabilityofCu toplantsis closely associated with total Cu content in the soil. 11 is t hus possible to predict Cu sufficiency based on the totdl Cu in soils (Lucas and Knezek 1972). Plantsgrown on minerał soils that contain less than

6 A/gg^_1 or organie soils having less than 30jigg^-1 oftotal Cu might show deficiencyof this element (Katyaland Randhawa 1983).

It has been shown that peat iscapable of bind-ing Cu ions morę strongly than other metals. The release of the ion into the soil solution in peat is slower compared to Cu adsorbed to minerał clays (McLaren. 1972). This is the result of complex formation or specific adsorption involving the