The use of chicken manure, lowland peat and highland peat briquettes on the growth of Macadamia integrifolia in an arid area of Pematang Tambun Village, Simalungun Regency

The catchment area of Lake Toba continues to experience a decline in quality due to frequent fires in this area. Various recovery measures in the form of reforestation are continuously being carried out but often fail due to the difficult terrain due to the steep slope and the rapid loss of water due to gravity. The water immediately dissipates to a lower elevation leading to the lake. As a result, this condition leaves an expanse of barren area that is only overgrown with weeds. This study aimed to see whether lowland and highland peat soil can be used as a water retaining material that has the same quality as manure and to obtain the right dose of this water retaining material to support the growth of Macadamia integrifolia plants. The study was designed using 3 types of water retaining material briquettes, namely: chicken manure, lowland peat and highland peat, each of which was divided into several treatments, namely: 0, 0.5, 0.75, 1.0, 1.25 and 1.5 kg/plant. The difficulty of the steep terrain makes it difficult for planting actions. Therefore, the technology of making briquettes is considered to be a solution. In addition, the conversion into briquettes gives a positive value to peat where acidic peat water can be removed so that the toxic effects of peat can be reduced. The results showed that the three types of briquettes significantly increased plant growth in terms of plant height, leaf area and crown area of M. integrifolia. Although the best plant growth performance was shown by the briquette dose of 1.5 kg/plant, the dose of 0.75 kg/plant seemed to have given no significant growth when compared to a dose of 1.0-1.5 kg/plant.