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Currently water is a very controversial subject for some. Basically in NZ, most of the agricultural water abstraction occurs in the East Coast and Central areas. However, the principles apply anywhere. It matters not whether the extraction is for rural or urban purposes. What matters is that it is happening with no thought given to aquifer recharge. Check out the meaning of abstraction; you may be surprised.

 

Freshwater abstraction for agriculture

 

We tend to think in terms of surface water. Underground aquifers are out of sight and out of mind. But surface and underground water are connected as one. Take it from the surface and it reduces the aquifer. Pump it from the aquifer and it reduces the river. Most of this occurs in summer when the flows are at their lowest. In short, one-way removal of water for crops and cities, will lead to drying the land out. This is the opposite result of our intentions.

A cross-section of a river is basically a concave structure. Below that the aquifer is a convex one; like two spoons with their humps touching. Extraction of water from either causes that one not to contribute to the other; more importantly it can cause separation of one source from the other. So how can we change that? Simply put it is a matter of diverting excess runoff water and allowing time for it to infiltrate back into the soil and eventually the aquifer. Give and you shall receive.

Some rivers have been straightened and stop-banked at to hasten the flow to the sea. This is a flawed concept, reflecting short term thinking. Those stop-banks need to lead to infiltration zones outside of the stop-banks limits where excess winter rain can be channelled for aquifer “duties.” Further inland, snow melt needs to be channelled in a similar way. There are dozens of solutions, but no political will do take any action whatsoever. Everything is borrowed from our grandchildren. Let’s leave things in a better state than we found them; not the opposite.

NZ is a relatively damp place, but irrigation is becoming more and more popular. This is a flawed concept given that under NPK science, we have not extracted anywhere near the potential production from the land by properly improving soil fertility in the first place. By increasing soil fertility using the Albrecht-Kinsey system, we can increase pasture DM and quality by >25% on many properties. The best figures I know are a 46% improvement in five years. This is happening all around the world. Not only that, soil water infiltration and retention will increase along with carbon content with some properties increasing carbon by 5t/ha per year. Topsoil and rooting depth are also increasing. Pests and diseases and their chemical rescue remedies take a back seat. Profitability increases and farming becomes an absolute pleasure again.

It does not stop with soil fertility either. This sentence is from a DairyNZ publication. After the 3-leaf stage, older (ryegrass) leaves die resulting in wastage and feed quality falls as dead material builds up. What absolute rubbish! The plants are under-nourished by the NPK system. Ryegrass plants grow up to 5 green leaves per tiller. How can you expect to increase production; when pasture is operating below its potential on two counts? One, the nutrition is lacking, and two, the rotation is too fast, being based on a premature 3-leaf cycle of one plant. But that is the system we work under. It’s self-limiting totally constrained by borders, boundaries and boxes.

Give Kiwi Fertiliser a call if you are interested in finding out how to improve your farming operations.

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