Impact of Watershed Restoration Based Agroforestry on Soil Quality in the Sub-Watershed Keduang, Wonogiri, Indonesia

Abstract

The upper Solo Wonogiri Watersheed size of the catchment is 135,000 hectares. It is divided into six sub watershed, i.e. the Keduang, Temon, Alang, Wuryantoro, Wiroko, and Upper Solo. The fact that occur in areas upper Solo watershed the zone of distric Wonogiri Central of Java, is currently large (> 90%) is the cultivation of seasonal crops with crops such as cassava, peanuts and not cultivation techniques cropping (Supriyadi, 2007). The implementation of restoration in subwatershed is one of several of cultivation system method that consider the importance of land sustainability. The objective of this research was to identify appropriate indicators for assessing the impact of longterm agroforestry systems on soil quality in areas upper Solo watershed the zone of distric Wonogiri Central of Java, Indonesia. The research was based on descriptive explorative through land surveys, while to know the value of the soil quality in Keduang subwatershed takes the point sample deliberately (purposive sampling). The Soil Quality Index (SQI) is determined by collecting data on indicators that have been selected for each soil function or Minimum Data Set (MDS). Assessment of soil quality using a scoring method data on every indicator. Soil quality index for the retoration in Keduang sub-watershed were 26,67-27,78 for native forest; 24,44-25,56 for agroforestry; and 23,33-26,67 for dry land. The average value of soil quality index in native forest is 27,04; in agroforestry is 24,81 and dry land is 24,07. In native forest value of soil quality is the highest than agroforestry and dry land. The result showed that according to soil quality index, the types of management of landuse could improve soil quality. The better the soil quality, the higher the SQI. Land utiliser foe native forest had better soil quality than agroforestry and dry land, while land utilised for dry land had significant different compossed to the agroforestry system.

The Influence of Two Different Time of Concentration Equations on the GIUH-based Flood Hydrograph Estimates of Keduang and Temon Sub-Watersheds, Indonesia

“…Where t c is the time of concentration (min), L is length of waterline (m), and V is dynamic parameter velocity (m/s). Substitution of equation ( 9) into equations (7) and (8) gives the dynamic parameter velocity of Kirpich and Ventura as written in equations ( 10) and (11), respectively.…”

“…Both Sub-watersheds lay at the watershed of Wonogiri Reservoir, Central Java, Indonesia (see Figure 1). The Wonogiri Reservoir was built as a flood control installation for the Upper Bengawan Solo River and functioned reducing the flood peak from 4000 m 3 /s into 400 m 3 /s [7,8]. The watershed area of Wonogiri Reservoir is approximately 1,260 km 2 .…”

Land Degradation and Option of Practical Conservation Concepts in Manna Watershed Bengkulu Indonesia

“…The agro-forestry system is a solution for the development of agriculture in the watershed. Agro-forestry systems can be a source of farmer income and at the same time maintain environmental services as well as sustain the biodiversity (Supriyadi, 2014). Agro-forestry practices are land use systems that have the potential of improving agricultural land uses and at the same time providing continuous benefits and alleviating adverse environmental effects at local, regional, and global levels (Sobola et al, 2015).…”