Changes of Soil Aggregate on Degraded Jasinga Ultisols by Soil Tillage and Organic Matter Practices

Soil aggregate is soil characteristics which is sensitive to change due to soil tillage. Organic matter practices and soil tillage difference have an important role in determining the quality and quantity of soil aggregate. The objective of this research is to study the quality changes of soil aggregation on Ultisols Jasinga degraded by various soil tillage and organic matter practices. This research was carried out at Jasinga Village, Jasinga Sub District, Bogor District in 2003 planting season (PS). The randomized block design with three replications was used. The Main plot was artificial desurfacing which consisted of three treatments, i.e: non-artificial desurfacing, 5 cm depth of artificial desurfacing, and10 cm depth of artificial desurfacing, whereas sub plot treatments were soil tillage and soil rehabilitation with Mucuna sp. (tillage+Mucuna sp.), no soil tillage and without rehabilitation (no tillage without Mucuna sp.), soil tillage without rehabilitation (tillage without Mucuna sp.), and no soil tillage with rehabilitation (no tillage+Mucuna sp.). The result of this research showed that periodic application of fresh organic matters was able to maintain the quality of macroaggregate on eroded soil (0.36-15.47 cm). Minimum soil tillage application and continuos organic matter practices (>21 t ha-1 year-1) are soil conservation technique that has been able to maintain soil aggregate, even without rehabilitation with Mucuna sp. Various organic matters (Mucuna sp., plant waste, and flemingia) are needed to be applied periodically to maintain the quality of soil aggregate

Greenhouse Gas Emissions and Land Use Issues Related to the Use of Bioenergy in Indonesia

Biofuel use is intended to address the ever-increasing demand for and scarcer supply of fossil fuels. The recent Indonesia government policy of imposing 10% mixing of biodiesel into petroleum-based diesel affirms the more important biofuel role in the near future. Palm oil, methane from palm oil mill effluent (POME) and animal wastes are the most prospective agricultural-based biofuels. The production and use of palm oil is interlinked with land use and land use change (LULUC), while the use of methane from POME and animal wastes can contribute in reducing emissions. The current European Union (EU) and the potential United States (US) markets are imposing biodiesels' green house gas (GHG) emission reduction standards (ERS) of 35% and 20%, respectively relative to the emissions of petroleum-based diesel based on using the lifecycle analysis (LCA). EU market will increase the ERS to 50% starting1 January 2017, which make it more challenging to reach. Despite controversies in the methods and assumptions of GHG emission reduction assessment using LCA, the probability of passing ERS increases as the development of oil palm plantation avoid as much as possible the use of peatland and natural forests. At present, there is no national ERS for bioenergy, but Indonesia should be cautious with the rapid expansion of oil palm plantation on existing agricultural lands, as it threatens food security. Focusing more on increasing palm oil yield, reducing pressure on existing agricultural lands for oil palm expansion and prioritizing the development on low carbon stock lands such as grass- and shrublands on mineral soils will be the way forward in addressing land scarcity, food security, GHG emissions and other environmental problems. Other forms of bioenergy source, such as biochar, promise to a lesser extent GHGemission reduction, and its versatility also requires consideration of its use as a soil ameliorant

The Use of Mineral and Organic Soil Conditioner to Improve Soil Quality of Typic Kanhapludults Tamanbogo, Lampung

As soil conditioner, there are many functions of organic matter that would not be replaced by mineral material. Therefore, mineral soil conditioner is better focused on increasing quality of organic soil conditioner. The objective of the research was to obtain the effectiveness of soil conditioner formula (organic matter and zeolit) and its application technique (dose and phase application) in improving soil quality. The research was conducted at KP Tamanbogo, Lampung for three seasons (2006/2007). The experiment employed a split plot design with three reflications. Application techniques of soil conditioner (dose and phase aplication) as main plots and three types formula of soil conditioner as sub plots. Corn was used as test crop. Parameters observed were plant growth and production, and changes in soil properties. The results showed that soil conditioner that applied on Typic kanhapludults could significantly increased corn growth and yield. Soil conditioner with higher organic matter proportion has better effect on corn growth and yield as well as on physical soil properties, which indicated by soil permeability and aggregate stability. The addition of 20% of zeolit in soil conditioner formula increased soil microorganism activities, but the additional up to 30% decrease microorganism activities. The changes of organic matter and zeolit proportion in soil conditioner has significantly effect on soil pH and N content, but has no significantly effect on P, K content, and CEC. Compared to innitial soil condition, application of soil conditioner could increase CEC from <4 cmolc kg-1 to 5.85 cmolc kg-1 respectively. Soil conditioner was better to be applied periodically but must be done every season. For degraded soil such as at KP. Tamanbogo, soil conditioner was applied with 10 t ha-1 dose for innitial rehabilitation process, hereinafter with 5 t ha-1 annual crop season dose

Changes of Soil Organic Matter Fraction on Ultisols Jasinga by Soil Tillage and Organic Matter Practices

In situ organic matters, such as Mucuna sp., Flemingia sp., and plant residues differ in quality (in terms of lignin, cellulose and nutrients contents). Such difference determines soil organic matter content especially labile fraction that could effect on soil properties. The aims of this research were to study: 1) the effects of various sources and quality of organic matters on soil organic fraction, and 2) the relationships between the changes of particulate organic matter and C-microbes (POM and Cmic) and soil quality indicators. The experiments were conducted in greenhouse of the Center for Soil and Agroclimate Research and Development, Bogor, from January to May 2003. The factorial completely randomized design was used with three replications. The first factor was the method of organic matters application: 1) mulch on soil surface and 2) incorporated with soils. The second factor was the sources of organic matters (dosage in equvalent with 2% organic C), i.e: 1) Mucuna sp., 2) Flemingia sp., 3)maize residue, 4) mixture of Mucuna sp., and Flemingia sp., 5) mixture of Flemingia sp. and maize residue, 6) mixture of Mucuna sp. and maize residue, and 7) mixture of Mucuna sp., Flemingia sp., and maize residue. The results showed that on organic matter application with incorporated method, C/N ratio and lignin content of organic matter have positive correlation with organic C, Cmic and Cmic/Corg, but have negative correlation with POMp. The changes of soil qualities caused by short term organic matter application could be seen from the changes of labile fraction of organic matter. When organic matter was incorporated, POMtand POMt/Corg have positive correlation with bulk density, but have negative correlation with RPT, PDC, available K, and total- N. When organic matter was spreaded on the soil surface, Cmic has positive correlation with available P. The changes on labile fraction (Cmic and POMt) was easy to be detected in short period, thus the changes of physical characteristics and the availability of macro nutrients is easy to be predicted