Agricultural Info

S.A.Composters agricultural info What are some features of good soil? Any farmer will tell you that a good soil:

  • feels soft and crumbles easily,
  • drains well and warms up quickly in the spring,
  • does not crust after planting,
  • soaks up heavy rains with little runoff,
  • stores moisture for drought periods,
  • has few clods and no hardpan,
  • resists erosion and nutrient loss,
  • supports high populations of soil organisms,
  • has a rich, earthy smell,
  • does not require increasing inputs for high yields,
  • produces healthy, high-quality crops.

Understanding the principles by which native soils function can help farmers develop and maintain productive and profitable soil both now and for future generations.  The soil, the environment, and farm condition benefit when the soil’s natural productivity is managed in a sustainable way.  Good soil management produces crops and animals that are healthier, less susceptible to disease, and more productive.

An acre of living topsoil contains approximately 900 pounds of earthworms, 2,400 pounds of fungi, 1,500 pounds of bacteria, 133 pounds of protozoa, 890 pounds of arthropods and algae, and even small mammals in some cases. Therefore, the soil can be viewed as a living community rather than an inert body. Soil organic matter also contains dead organisms, plant matter, and other organic materials in various phases of decomposition. Humus, the dark-colored organic material in the final stages of decomposition, is relatively stable. Both organic matter and humus serve as reservoirs of plant nutrients; they also help to build soil structure and provide other benefits. All these organisms from the tiny bacteria up to the large earthworms and insects. interact with one another in a multitude of ways in the soil ecosystem. Organisms not directly involved in decomposing plant wastes may feed on each other or each other’s waste products or the other substances they release.

Appropriate mineral nutrition needs to be present for soil organisms and plants to prosper. Adequate levels of calcium, magnesium, potassium, phosphorus, sodium, and the trace elements should be present, but not in excess.

Benefits of organic matter

The benefits of a topsoil rich in organic matter and humus are many. They include rapid decomposition of crop residues, granulation of soil into water-stable aggregates, decreased crusting and clodding, improved internal drainage, better water infiltration, and increased water and nutrient holding capacity. Improvements in the soil’s physical structure facilitate easier tillage, increased water storage capacity, reduced erosion, better formation and harvesting of root crops, and deeper, more prolific plant root systems.

The primary factors affecting organic matter content, build-up, and decomposition rate in soils are oxygen content, nitrogen content, moisture content, temperature, and the addition and removal of organic materials. All these factors work together all the time. Any one can limit the others. These are the factors that affect the health and reproductive rate of organic matter decomposer organisms.

All the soil organisms mentioned previously, except algae, depend on organic matter as their food source. Therefore, to maintain their populations, organic matter must be renewed from plants growing on the soil, from animal manure or compost. When soil livestock are fed, fertility is built up in the soil, and the soil will feed the plants.

Compost is not as good a source of readily available plant nutrients as raw manure. But compost releases its nutrients slowly, thereby minimizing losses. Quality compost contains more humus than its raw components because primary decomposition has occurred during the composting process. However, it does not contribute as much of the sticky gums and waxes that aggregate soil particles together as does raw manure, because these substances are also released during the primary decomposition phase. Unlike manure, compost can be used at almost any rate without burning plants. Composting also reduces the bulk of raw organic materials. especially manures, which often have a high moisture content.

Erosion control

Topsoil is the capital reserve of every farm. Ever since mankind started agriculture,  erosion of topsoil has been the single largest threat to a soil’s productivity and consequently, to farm profitability. The major productivity costs to the farm associated with soil erosion come from the replacement of lost nutrients and reduced water holding ability, accounting for 50 to 75% of productivity loss. Soil that is removed by erosion typically contains about three times more nutrients than the soil left behind and is 1.5 to 5 times richer in organic matter. This organic matter loss not only results in reduced water holding capacity and degraded soil aggregation, but also loss of plant nutrients, which must then be replaced with nutrient amendments.

Protecting the soil from erosion is the first step toward a sustainable agriculture. Since water erosion is initiated by raindrop impact on bare soil, any management practice that protects the soil from raindrop impact will decrease erosion and increase water entry into the soil. The soil should be covered to protect it from temperature extremes as well.

Mulches, cover crops, and crop residues serve these purposes well.

Tillage

While tillage has become common to many production systems, its effects on the soil can be counter-productive. Tillage can be beneficial or harmful to a biologically active soil, depending on what type of tillage is used and when it is done. Tillage affects both erosion rates and soil organic matter decomposition rates.

Tillage smoothes the soil surface and destroys natural soil aggregations and earthworm channels. Porosity and water infiltration decrease following most tillage operations. Plow pans may develop in many situations, particularly if soils are plowed with heavy equipment or when the soil is wet. Tilled soils have much higher erosion rates than soils left covered with crop residue. In fact, tillage for production of annual crops has created most of the erosion associated with agriculture. Perennial grain crops not requiring tillage provide a promising alternative for drastically improving the sustainability of future grain production.

Shallow tillage incorporates residue and speeds the decomposition of organic matter by adding oxygen that microbes need to become more active.

Both no-till and reduced-tillage systems provide benefits to the soil. The advantages of a no-till system include superior soil conservation, moisture conservation, reduced water runoff, long term buildup of organic matter, and increased water infiltration. A soil managed without tillage relies on soil organisms to take over the job of plant residue incorporation formerly done by tillage. On the down side, no-till can foster a reliance on herbicides to control weeds and can lead to soil compaction from the traffic of heavy equipment.  

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