EFFECTS OF MULCHING AND FERTILISER ON NUTRIENT DYNAMICS OF SAND TAILINGS GROWN WITH ACACIA HYBRID SEEDLINGS

Studies on the contribution of oil palm empty fruit bunch (EFB) mulch mat and its impact on fertiliser loss through leaching on sand tailings are lacking. Sand tailings in Malaysia formed through tin mining activities are problematic soils for agriculture and forestry. An experiment with two types of EFB mulch mat applied in combination with NPK (nitrogen:phosphorus:potassium) fertiliser was established in pots containing sandy tin tailing soil to assess their effects on soil nutrient enrichment and leaching. Application of mulch mat reduced leaching of fertiliser compared with treatments without mulch mats. Incorporating fertiliser inside the mulch mat at the production stage could be the best way of applying inorganic fertiliser on sandy soils as the amounts of N, P and K loss was reduced significantly compared with treatments without mulch. There was poor synchronisation between fertiliser input and plant nutrient demand. The amount of fertiliser applied seemed to be in excess of the uptake capacity by roots especially for highly mobile nutrients N and K. Application of mulch mat on sand tailings however did not ameliorate the soil nutrient properties after 16 weeks. This could be due to the porous nature of the sand tailings. Tidak banyak kajian dijalankan terhadap manfaat tikar sungkupan yang diperbuat daripada tandan kosong kelapa sawit (EFB) dan keberkesanannya dalam mengawal kehilangan baja melalui luluh larut di tanah bekas lombong. Aktiviti perlombongan bijih timah di Malaysia meninggalkan tanah bekas lombong yang bermasalah untuk kegiatan pertanian dan perladangan hutan. Satu kajian dijalankan terhadap dua jenis tikar sungkupan EFB yang diaplikasi bersama-sama baja NPK (nitrogen:fosforus:kalium) di atas tanah bekas lombong yang diisi dalam tabung besar untuk menilai kesannya terhadap peningkatan nutrient tanah dan luluh larut. Hasil kajian menunjukkan penggunaan tikar sungkupan berupaya mengurangkan jumlah luluh larut baja apabila dibandingkan dengan rawatan kawalan. Jika baja dimasukkan ke dalam tikar sungkupan semasa tikar tersebut dihasilkan, kehilangan N, P dan K melalui luluh larut berkurang secara signifikan berbanding rawatan tanpa sungkupan. Ini mungkin merupakan cara terbaik untuk membubuh baja inorganik di tanah bekas lombong. Input baja dan keperluan baja oleh pokok tidak selari. Kadar baja yang diberi adalah berlebihan berbanding kapasiti penyerapan akar lebih-lebih lagi untuk nutrien mudah larut seperti N dan K. Aplikasi tikar sungk