What is Sediment

What is the sediment that is clogging our waterways and polluting the lake?

Below are a few video demonstrations of soil infiltration vs soil run off. These demonstrate why in recent times WECA has been focused on soil and soil health. Agricultural systems within NZ have been focused on output and growth and failed to identify the collapse of the soil and microbial life which supports the whole system.

In a collapsed compacted soil, the water fails to infiltrate, making farmers increasing reliant on external irrigation. When NZ farms, on average, receive 1000mm of rain per annum, it’s a real failure of the ecosystem to need irrigation on pastureland.

Rainfall Simulation demonstrating infiltration and erosion on tilled and untilled soil.


Emaline’s demo of Water Infiltration – Aggregated vs Non-Aggregated Soil.


Water Movement Through Soil Profiles Under Three Different Farming Systems


Soil Carbon – How Nature builds the Soil Carbon Sponge


Can we stop rains from taking away our topsoil

One of the more interesting aspects of the last video from ‘Kiss the Ground’ is it’s similarities to the NZ wet climate. Meaning our chemical agricultural topsoils run off into our waterways. But in the 1930s America experience the ‘Dust Bowl’ whereby in a drought the agricultural topsoil blew away, creating dust storms and destroying crops. Causing a famine. A significant amount of research was done to avoid this crisis happening again – much of it forgotten after the second world war and the adoption of german agrochemicals.

For those of you interested further a great book is ‘Tree Crops’ by J Russell Smith, written in 1929. It focuses on a permanent agriculture crop integrating producing trees. Certainly it seems under the accords NZ has signed for permanent forests, some of these trees would be a better option than the Pine.

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