Effect of land use and land management on soil erosion and soil quality in a typical small watershed in Java, Indonesia | |
| Author | Bambang Hermiyanto |
| Call Number | AIT Diss. no.AE-04-08 |
| Subject(s) | Land use--Indonesia Soil erosion--Indonesia Soils--Indonesia--Quality |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Technical Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. AE-04-08 |
| Abstract | The effects of land use and land management at the watershed scale on runoff, soil loss and nutrient losses are important criteria for a typical small agricultural watershed in Java, Indonesia. The study addresses the relationships between three small watersheds-with different land use and management practices-and soil and nutrient losses; and between land units-with different slope class, soil type and land use-and soil quality, The three main aims of this study were to identify important soil-quality indicators and develop soil-quality indexes for different land uses and land-management practices; characterize the land-use systems and management practices in terms of their influence on soil erosion and soil quality; and assess runoff, and soil and nutrient losses at the watershed level in relation to terrain characteristics and prevailing land use and management. Hydrological field measurements-consisting of rainfall, runoff, and soil loss-were made over a two-year period, i.e., 2000 and 2001, while sediment sampling for nutrient losses measurement were conducted during a one-year period 2001. Field surveys were conducted to identify the biophysical conditions and to compile an inventory of land use. On the basis of ground slope, soil type and land use, land units were identified, which were assumed to represent typical soil-quality conditions. Soil sampling for the determination of 18 different soil chemical and physical characteristics was based on these land units, Principal components analysis (PCA0, factor correlation and analysis of variance were used to identify the overall soil-quality attributes for the area and develop a compound soil quality index (SQI). In the area, Inceptisols and alfisols are dominant. The three watersheds are characterized by distinctly different land uses, i.e., annual food and grass cropping in tegalan, perennial cropping (rambutan orchard) and bushes in rambutan and perennial cropping (rambutan orchard) and mixed garden in Kalisidi. Based on different slope, sil type and land use, eleven land-units were determined, i.e., 3, 3, and 5 land units in Tegalan, Rambutan, and kalisidi, respectively, Tegalan has 2 land-units of annual food cropping and 1 land-unit of grass; Rambutan has 2 land-units of rambutan orchards and 1 land-unit of mixed garden. Generally, the soil-fertility status of the watershed is low, especially for land planted with annual food crops. With different land use systems over time, the agronomic practices also differ according to the requirement of the crops. The applications anymore in three years' time). The use of these inputs led to a significant increase in land productivity, While in Tegalan, the low rate of only n fertilizer and organic fertilizer (cattle during) applications and the land use of annual food crops with low land-cover has led to the increase of soil loss and the decrease of soil fertility, Annual rainfall and erosivity during the study period were within the normal expected range for the area, Differences in soil erosion from the 3 watersheds-estimated in terms of sediment yield- can be attributed mainly to differences in land-cover. A clear example are the higher runoff rates and sediment yields - despite lower rainfall and erosivity values- from the Rambutan watershed during 2000 when there was significant soil disturbance due to temporary encroachment into the rambutan fruit-tree plantations of r the cultivation of cassava. The data indicate that nutrient losses due to erosion are a major cause of soil fertility depletion in the area, Soil management practices to improve the levels of P, K and organic matter world be required to compensate for losses of plant nutrient and to improve soil-quality in general. Six statistically significant soil-quality indicators (i.e., soil attributes) were identified for the watershed. Most of these indicators relate to the physical characteristics and the organic matter content, i.e., texture (clay), available P, water stable aggregates (WSA), hydraulic conductivity (HC), soil organic carbon (SOC), and bulk density, These indicators were used for the minimum dataset to develop compound soil-quality indexes (SQIs). The indices clearly showed that overall, rambutan orchards, bushland, and grassland land uses maintain higher soil quality than mixed garden and annual food cropping land uses. in addition, mixed garden land use maintains higher soil quality than annual food cropping land use. As addressed in this study, soil quality describes the essential soil conditions that set the limiting frame for long-term soil use. It seems that soil quality is strongly correlated with soil structure. The three decisive indicators in the SQIs -those indicators that can most clearly reveal soil quality changes- are available P, soil aggregate (WSA), and Soil organic carbon (SOC). Therefore, approaches to maintain and enhance soil quality in the study area must be linked to better P and organic fertilizer application and management. To achieve sustainable land use in the study area, land-use systems and technologies need to be adopted at the farm level that reduce soil and nutrient losses and soil degradation risks, increase appropriate P fertilizer application and the efficiency of organic matter cycling, and maintain favorable soil structure. These should include changing land use from annual cropping to perennial cropping (for an example rambutan orchard), improving regular terraces, adding proper fertilizers use (especially P-fertilizer) and ensuring better soil organic matter management. Some soil organic matter management practices that can be chosen individually or applied together are incorporation of crop residues, rotation with legumes, integration of livestock and introduction of organic framing' into farming systems. lastly, with improved land management, the decreasing trends of soil quality in the study are can probably be reversed in the long run. |
| Year | 2004 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. AE-04-08 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Agricultural and Food Engineering (AE) |
| Chairperson(s) | Zoebisch, Michael, Albert; |
| Examination Committee(s) | Zoebisch, Michael, Albert;Singh, Gajendra;Ranamukhaarachchi, S.L;Clemente, Roberto,; |
| Scholarship Donor(s) | DUE Project, University of Jember MSEC Project - CSARD; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2004 |