Progress 10/01/02 to 09/30/05
Outputs
Work on this grant continues under a different project number for which a progress report is provided separately. This phase used greenhouse simulation for rehabilitating eroded Oxisols. Physical soil quality factors were reflected by compaction as measured by bulk density; chemical/nutrient quality factors were reflected by available N, and biological factors were reflected by enrichment in organic amendments. Corn plants were monitored by weekly measurements of plant heights. In this first phase, the dry yields of the corn shoots were not significantly affected by soil bulk density but there was a highly significant difference between the applied nitrogen levels and in response to organic amendments. Yields in amended soils were dramatically increased with nitrogen supplement, except for chicken manure because this material is already highly enriched in nitrogen.
Impacts
Eroded tropical soils possess severe constraints that affect their productivity and contribution to the health of the environment. Restoring productivity and quality to these soils, therefore, requires improvements in soil chemical, physical and biological properties. In this phase of the project, a combination of physical manipulation by appropriate tillage, nutrient restoration by fertilization, and biological enhancement by organic amendments offer a promising strategy for integrated management of soil quality restoration in eroded soils.
Publications
- No publications reported this period
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Progress 10/01/03 to 09/30/04
Outputs
Greenhouse simulation of eroded Oxisol rehabilitation continued. Physical soil quality factors were reflected by compaction as measured by bulk density. Densities of 1.0 and 1.3 Mg/m3 were used. Chemical/nutrient quality factors were reflected by available N (0, 0.5 and 1.0%). Biological factors were reflected by enrichment in organic admendments, namely peat moss, redwood, and chicken manure added at levels of 10%, 25% by volume. Leachates were collected weekly and analyzed for nutrient content. The plants were monitored by weekly measurements of plant heights. In the first experiment, the dry yields of the corn shoots were not significantly affected by soil bulk density. In contrast, there was a highly significant difference between the two nitrogen levels and in response to organic amendments. Yields in amended soils were dramatically increased with nitrogen supplement, except for chicken manure because this material is already highly enriched in nitrogen.
Impacts
Eroded tropical soils possess severe constraints that affect their productivity and contribution to the health of the environment. Restoring productivity and quality to these soils, therefore, requires improvements in soil chemical, physical and biological properties. In this phase of the project, a combination of physical manipulation by appropriate tillage, nutrient restoration by fertilization, and biological enhancement by organic amendments seem to be a promising strategy.
Publications
- No publications reported this period
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Progress 10/01/02 to 09/30/03
Outputs
The experiments on greenhouse simulation of eroded Oxisol rehabilitation continued. Pioneer Hybrid 1035 field corn is used as an indicator crop. Soil bulk densities of 1.0 and 1.3 Mg/m3 were used to evaluate root penetration resistance in 2 Kg containers. Two levels of supplemental nitrogen (0, 1.8 g per pot) were compared in the presence of three types of organic additives (peat moss, redwood, and chicken manure). The latter were added at levels of 10%, 25% by volume. Thus, there are total of 28 treatments including controls, and each treatment has 3 replications. To ensure that soil quality indicators include the soils ability to regulate water quality, plastic leachate collectors were installed in each soil container. Leachates were collected weekly and analyzed for nutrient content. The plants were monitored closely with weekly measurements of plant heights. The first experiment was concluded at the end of the 5th week after planting. Based on the dry yields of
the corn shoots, we found no significant difference between the two bulk densities. However, there was a highly significant difference between the two nitrogen levels. Yield benefits of organic amendments were dramatically increased with nitrogen supplement. The exception was chicken manure for which dry yields decreased after nitrogen was added. This is explained by the fact that this material is already highly enriched in nitrogen. Overall, the two best yields were obtained with 10% of peat moss with nitrogen and chicken manure without nitrogen added.
Impacts
Eroded tropical soils possess severe constraints that affect their productivity and contribution to the health of the environment. Restoring productivity and quality to these soils, therefore, requires improvements in soil chemical, physical and biological properties. In this early phase of the project, a combination of physical manipulation by appropriate tillage, nutrient restoration by fertilization, and biological enhancement by organic amendments seem to be a promising strategy.
Publications
- No publications reported this period
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Progress 10/01/01 to 09/30/02
Outputs
No progress to report. This project was initiated on October 1, 2002.
Impacts
(N/A)
Publications
- No publications reported this period
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