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