www.sare.org publications building-soils-for-better-crops-3 organic-matter-management Organic Matter Management As we discussed in chapter 3, there are no generally accepted guidelines as to how much organic matter should be in a particular soil. And it is difficult to be sure exactly why problems develop when organic matter is depleted in an individual field. However, even in the early 20th century, agricultural scientists proclaimed, “Whatever the […]
www.sare.org publications building-soils-for-better-crops-3 summary-and-sources-5 Summary and Sources Summary The overall strategies of ecologically sound crop and soil management focus on prevention of factors that might limit plant growth. These three strategies are to grow healthy plants with enhanced defense capabilities, stress pests, and enhance beneficial organisms. There are a variety of practices that contribute to these overall goals and have been discussed […]
www.sare.org publications building-soils-for-better-crops-3 ecological-crop-and-soil-management Ecological Crop and Soil Management We’ll discuss ecological crop and soil management practices as part of a general framework for approaching ecological crop management (figure 8.4). The heart of the matter is that the strength of the system is improved by creating improved habitat both above ground and in the soil. Although it is somewhat artificial to talk separately about […]
www.sare.org publications building-soils-for-better-crops-3 ecological-principles-for-agriculture Ecological Principles for Agriculture Approaching agriculture and soil management from an ecological point of view means first understanding the characteristics that comprise strong natural systems. Let’s take a look at overall strategies that can contribute to similar strength of crops, animals, and farms. Then we’ll briefly discuss practices that contribute to creating vital and strong agricultural systems (discussed in […]
www.sare.org publications building-soils-for-better-crops-3 plant-defenses-management-practices-and-pests Plant Defenses, Management Practices, and Pests Before discussing the key ecological principles and approaches to soil management, let’s first see how amazing plants really are. They use a variety of systems to defend themselves from attack by insects and diseases. Sometimes they can just outgrow a small pest problem by putting out new root or shoot growth. Many plants also produce […]
www.sare.org publications building-soils-for-better-crops-3 summary-and-sources-4 Summary and Sources Summary There is true nutrient cycling on most farms as crop residues or manures produced by animals fed crops grown on the farm are returned to the soil. However, there are potentially large flows of nutrients onto and off of farms, and we are concerned about cases where the flows are unbalanced. The inflow occurs as […]
www.sare.org publications building-soils-for-better-crops-3 implications-of-nutrient-flow-patterns Implications of Nutrient Flow Patterns Long-distance transportation of nutrients is central to the way the modern food system functions. On average, the food we eat has traveled about 1,300 miles from field to processor to distributor to consumer. Exporting wheat from the U.S. Pacific Northwest to China involves an even longer distance, as does the import of apples from New […]
www.sare.org publications building-soils-for-better-crops-3 differing-flow-patterns Differing Flow Patterns Different types of farms may have distinctly different nutrient flow patterns. Farms that exclusively grow grain or vegetables have a relatively high annual nutrient export (figure 7.2a). Nutrients usually enter the farm as either commercial fertilizers or various amendments and leave the farm as plant products. Some cycling of nutrients occurs as crop residues are […]
www.sare.org publications building-soils-for-better-crops-3 summary-and-sources-3 Summary and Sources Summary Soil degradation is one of the world’s great environmental problems. At the same time as rivers are contaminated with sediments eroded from soils, severe erosion in many parts of the world results in a significant decrease in soil productivity. Although the immediate cause for water erosion may be intense rainfall, there are a number of […]
www.sare.org publications building-soils-for-better-crops-3 chemical-contamination-of-soil Chemical Contamination of Soil Soils can be contaminated with chemicals—either naturally or by human activity—to such an extent that crops are adversely affected. In this section we’ll start with a discussion of problems of saline and sodic (alkaline) soils, normally found in arid and semiarid regions. Then we’ll discuss other types of chemical contamination. Sodic and Saline Soils Special soil […]