Sustaining Soil

The nltimate in no-till agriculture is the use of perennial plants that do not have to be planted each year. Trees in orchards and grapevines in vineyards are certainly such plants. The roots of perennial plants are very effective in holding plants in place. Efforts to develop perennial plants that prodnee grain have had only limited sncc ess so far. This is because a productive grain-bearing plant 

FIGURE 11.7 Construction of terraces on the contour of land and planting crops on the contour are practices that have been very effective in reducing soil erosion. 

Buffer strip of grass to filter suspended soil and nutrients from runoff 

FIGU RE 11.8 Alley cropping of crops between rows of trees running across sloping land can be an effective means of practicing agroforestry sustainably. 

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Declining amounts of arable land, increasing world populations, and increasing costs of fertilizer and food and energy needs will make it increasingly difficult to maintain our soil resources. A key component for sustaining soil productivity is the maintenance of soil organic carbon (SOC). SOC maintenance requires the amount of carbon added to the system to equal the amount of relic carbon mineralized... 

Tiessen, H., Cuevas, E., and Chacon, P. (1994). The role of soil organic matter in sustaining soil fertility. Nature. 371,783-785. 

Glaser, B., Guggenberger, G., Haumaier, L., and Zech, W. (1998a). Sustainable soils in the Brazilian Amazon. In Humic Substances Downunder Understanding and Managing Organic Matter in Soils, Sediments, and Waters, 9th IHSS Conference, Adelaide, Australia. 

Romheld, V., and Neumann, G. (2006). The rhizsosphere Contributions of the soil-root interface to sustainable soil Systems. In Biological Approaches to Sustaible soil Systems, Uphoff, N., et al., eds., Taylor Francis, New York, pp. 91-107. 

EC (2001a). Organic contaminants in sewage sludge for agricultural use. In H. Langenkamp, and P. Part (eds.), European Commission, Joint Research Centre, Institute for Environment and Sustainability, Soil and Waste Unit. 

Vanlauwe, B. (2004) Integrated soil fertility management research at TSBF the framework, the principles, and their application.- In Bationo, A. (ed.) Managing Nutrient Cycles to Sustain Soil Fertility in sub-Saharan Africa.-Academy Science Publishers, Nairobi, Kenya. 

Lobo MC. (2007). Sustainable soil remediation. The use of combined technologies. Proceedings of the Sixth Symposium on Electrokinetic Remediation, Vigo, Spain. 

What agiiculmral practices are essential to sustaining soil productivity ... 

A part of the crust crucial for the existence of humans and most other nonaquatic life forms is the thin layer of weathered rock, partially decayed organic matter, air spaces, and water composing soU that supports plant life. Were Earth the size of a geography classroom globe, the average thickness of the soil layer on it would be only about the size of a human ceU The top layer of soil that is most productive of plants is topsoil, which is often only a few centimeters thick in many locations or even nonexistent where poor cultivation practices and adverse climatic conditions have led to its loss by wind and water erosion. The conservation of soil and enhancanent of soil productivity are key aspects of sustainability. Soil is discussed in detail in Chapter 10. 

Management Strategies for Sustaining Soil Productivity Via Agroforestiy Systems... 

On add, infertile soils (Oxisols, Ultisols, Dystropepts, Psamments, and Spodosols) the potential of trees to sustain soil productivity Hes in their role for maximizing soil cover (via canopies and mulch) and minimizing the loss of scarce nutrients via rainfall run off, soil erodon, and leaching 4). Due to reduced nutrient losses in systems with trees, the nutrient use efficiency of relatively small amounts of chemical fertilizers can be significantly improved. 

We suggest the following strategies to enhance the potential of agroforestiy systems to sustain soil productivity on recently deforested add, infertile soils in the Amazon ... 

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