Ameliorasi Tanah Gambut dengan Air Laut Mineral Zeolit dan Pasir Vulkan serta Pengaruhnya pada Tanaman Padi Sawah

Abstract

The study aimed to determine the effect of amelioration of seawater, zeolite, volcanic sand and combination of all ameliorants in peat soil from Inbuhan Batu and Asalnn Distric ltove been condrcted in the greenhouse and at Toba plateau peatland, Humbang Hasundutan Distric, Sumatera (Jtara Province. The provision of brackish water and sea water that are flowed vertically (eaching) and incubated for 4 and 8 weeks wcts able to increase the decomposition rate tltat is characterized by the lower of C/N, decreasing cation exchange capacity (CEC) and increasingof exchange bases. But also increase the soil acidity and electric conductivtty (EC) up to more tlwn 4 dS/m Provision of sea water with the lower concentration range (0, 500, |000, 1500 ml) of seawater combinedwith 0, 100, 200 g mineral of zeolite per pot into I0 kg of wet peat and observed for 3 months, indicating that zeolite mineral is capable ofsupporting the peat soil properties and keep the pH not decrease and keep EC not irrcrease drastically, even on same observation the zeolite is able to increase the pH and decrease the EC ofpeat soil. Increasing the concentration of sea water also caused a decline in the value of soil CN and CEC as well as the increasing of bases exchange in the adsorption surface site. Increasing the ru.tmber of bases is effected by the concentration of ions in sea water supplied and also influenced by the incubation period time in which Na-uchonge increased in highest point in the second month observation K, Ca and Mg exchange increased at third month, but no ircreasing in Ca exchange in first month. kolite mineral decreased of Mg-exchange. CEC increased in the 3rd month afier decline in I and 2 month observotion. The provision of sea water effective in increasing the base saturation of peat soil but zeolite slight depressed it. Addition of 200 dpot mineral zeolite ; 1000 g/pot volcanic sand and mix 200 g zeolite + 1000 g volcanic sand/pot is able to increase the pH of the peat soil, but after givtng of 500 , |000 and 1500 ml sea water through leaching repeatedly causing the peat soil pH decreased and peat soil EC increased. Sea water seems to be effective in increasing the rate of decomposition of the peat soil, causing the release of organic acids which indicated by increasing of acidity ofpeat. Volcanic sand most effective in irweasing soil bulk densitlt, P-available ard vegetative plant growth, whereas the sea water is improving the properties of peat soils through increasing bases and decreasing the over number of soil CEC so that the soil base saturation becomes increased. Provision of 500 ml of sea water combinedwith 1000 gvolcanic sand per pot and mix 200 g zeolite + 1000 g volcanic sand per pot gives best results for vegetative rice plants. Experiments in the field with the provision of 5000 g volcanic sand; 5000 g volcanic sand + 2500 ml of sea water and the combination of 500 g zeolite + 5000 gvolcanic sand + 2500 ml seawater per plot (2x2 mz) conducted in plateau peat rice field at Hutabagasan Village, Dolok Sanggul Sub district, Humbang Hasundutan District as a validation of greenhouse experiment. The results showed Oryza sativa var. dendang hybrid produced growth better than O. sativa var. sipiaraja as the local variety. The ameliorant is suppressing the growth of rice plants, especially the dendang hybrid variety