Holding rain water for future use is one of the topics that is being discussed recently.
We are having really dry spells followed by really wet weather. This not ideal for any of us. Many are feeling helpless in the face of floods and the devastation that it brings. The clean-up from these events is both time consuming and costly. People who monitor our rivers also tell us that there are significant changes to the rivers as the flood size and frequency increase.
As we shift into a new pattern of weather events, how can we improve our resilience of our land and farming practices to improve our wild swings from drought to flooding.
As well as infrastructure preparation and water storage which comes at a significant cost, there is an opportunity that lies beneath our feet.
Soil carbon is a gigantic sponge. It is estimated that an extra one percent of carbon that is 30 centimetres deep will increase the water holding capacity of the soil by 187,000 litres per Hectare. To put some context to this, 10 Hectares of soil with one percent extra carbon would hold the amount of water that is in an Olympic swimming pool. This is a significant amount of water. A healthy well-functioning loam soil which has an increase of five percent of soil organic matter through developing new soil management practices will store approximately one million litres of water per Hectare to a depth of 30 centimetres.
Scientists tell us that a top performing healthy loam soil with very high organic matter (OM) is capable of infiltrating up to 250 mm per hour of rainfall in one hour. Bearing in mind rainfall that totals over 40mm per hour or more can bring catastrophic surface flooding such as occurred in Tasman during Cyclone Gita, the potential for soils therefore to both mitigate localised on-farm damage and downstream flood damage, while storing water for summer droughts, is immense.
Soil infiltration rates give a good overview of how well your own soil is functioning in relation to water capture and will only cost a little of your time. To find out how, contact us at Fertilizer NZ.
The more of the heavy downpour can infiltrate your soil, the less this water will impact your farm and your neighbours downstream. Visualise the worst rainstorm possible on your property, imagine if the bulk of it ends up running off the surface of your property and concentrating into the gully flow rather than soaking in. This is where a picture of poor soil infiltration rates become apparent during an unforeseen storm.
Fertilizer NZ can help in conducting the infiltration tests and show how more carbon can be added to your soil to mitigate some effects of a storm and lead to having a lesser impact on your property when a drought occurs.
Holding rain water for future use