| One of the most difficult problems found in | | | | |
| many parts of Australia is the presence of | | | | Irrigation In Hobby Farm |
| excess salt in the soil. Soil salinity is an | | | | |
| indication of the level of soluble chemical | | | | Sadly, salt accumulation has become a concern |
| compounds present. | | | | on my hobby farm due to the dry conditions |
| | | | and lack of fresh irrigation water. Reduced |
| Salinity And Natural Salts | | | | rainfall has resulted in the build up of salt |
| | | | near the soil surface. This occurs as water |
| Salts are released naturally when rocks break | | | | evaporates from the soil surface and crystals |
| down, the most predominant being sodium | | | | form. Irrigation restrictions mean I am |
| chloride or common salt. Other salts include | | | | unable to wash excess from near the root |
| compounds of magnesium, potassium and | | | | system of the young trees and these young |
| calcium. When the levels become elevated | | | | plants are showing signs of stress. I expect |
| soils are damaged and crop production is | | | | many of the young trees to be damaged and not |
| diminished. | | | | survive the next summer. Increased levels of |
| | | | salt are also causing the formation of a |
| Salt problems occur naturally in the | | | | crust or hardening of the soil surface. This |
| landscape, but many areas become saline due | | | | is damaging the basic structure of the soil |
| to excess clearing of vegetation, over | | | | and affecting the germination of some plant |
| cultivation and poor irrigation practices. | | | | seeds. |
| The end result is that plants find it more | | | | |
| difficult to absorb water from the soil; | | | | Soil Salinity Management |
| plants wilt more readily, produce less growth | | | | |
| and in severe cases tissues are damaged. | | | | These methods include: |
| Eventually sensitive plants will die and salt | | | | |
| affected areas show a greatly reduced variety | | | | - Raising soil levels by mounding the soil |
| of plant growth. | | | | before planting, |
| | | | |
| Salt Crystals And Soil Test | | | | - Adding organic matter such as compost, |
| | | | |
| In extreme cases a white crust of dried salt | | | | - Not over cultivating soil and planting salt |
| forms on the soil surface and very few plants | | | | tolerant crops. |
| are able to survive. | | | | |
| | | | There is however no substitute for a good |
| The standard unit used when measuring salt | | | | rain as this will wash away much of the salt |
| levels is deciSiemens per metre (ds/m). This | | | | which accumulates near the soil surface |
| is measured using an electrical conductivity | | | | during times of drought. |
| meter (EC meter). The greater the level of | | | | |
| dissolved salt, the higher the reading These | | | | Salt control is one of the more important |
| readings can be converted into a measure | | | | problems to be faced if the hobby farm is to |
| which is easier to visualise known as parts | | | | sustain a diverse range of plants and |
| per million (ppm). A 1000 ppm water sample | | | | animals. Rainwater collection and storage |
| contains 1 gram of dissolved salt in each | | | | will be vital if this threat is to be |
| litre of water. Few crops are productive if | | | | overcome. It is an essential requirement for |
| levels are in excess of 2500 ppm. or 2.5 | | | | life, but in excess it is a sure recipe for |
| grams of dissolved salt per litre of water. | | | | disaster. |