Field investigations between 2002 and 2011 identified soil structural degradation to be widespread in SW England with 38% of the 3243 surveyed sites having sufficiently degraded soil structure to produce observable features of enhanced surface-water runoff within the landscape. Soil under arable crops often had high or severe levels of structural degradation. Late-harvested crops such as maize had the most damaged soil where 75% of sites were found to have degraded structure generating enhanced surface-water runoff. Soil erosion in these crops was found at over one in five sites. A tendency for the establishment of winter cereals in late autumn in the South West also often resulted in damaged soil where degraded structure and enhanced surface-water runoff were found in three of every five cereal fields. Remedial actions to improve soil structure are either not being undertaken or are being unsuccessfully used. Brown Sands, Brown Earths and loamy Stagnogley Soils were the most frequently damaged soils. The intensive use of well-drained, high quality sandy and coarse loamy soils has led to soil structural damage resulting in enhanced surface-water runoff from fields that should naturally absorb winter rain. Surface water pollution, localised flooding and reduced winter recharge rates to result from this damage. Chalk and limestone landscapes on the other hand show little evidence of serious soil structural degradation and <20% of fields in these landscapes generate enhanced runoff.
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A good little video showing different aspects that affect how well a soil manages the water that falls on it, will it run off or move down into the soil. Will it have a negative impact with run off and flooding or will it have a positive impact on plants and aquifers.
Altough only an introduction it touches on things such as soil compaction, drainage, leaching, capillary action in unsaturated soils, gravity as the dominant force that moves water downward in saturated soils. The soils texture and structure, platy, prismatic, columnar, granular, and blocky soils. Percolation rates and pore sizes etc
Leaked text of blockbuster report says changes in climate have already caused impacts on natural and human systems
Climate change has already left its mark “on all continents and across the oceans”, damaging food crops, spreading disease, and melting glaciers, according to the leaked text of a blockbuster UN climate science report due out on Monday.
Government officials and scientists are gathered in Yokohama this week to wrangle over every line of a summary of the report before the final wording is released on Monday – the first update in seven years.
Nearly 500 people must sign off on the exact wording of the summary, including the 66 expert authors, 271 officials from 115 countries, and 57 observers.
But governments have already signed off on the critical finding that climate change is already having an effect, and that even a small amount of warming in the future could lead to “abrupt and irreversible changes”, according to documents seen by the Guardian.
“In recent decades, changes in climate have caused impacts on natural and human systems on all continents and across the oceans,” the final report from the Intergovernmental Panel on Climate Change will say.
Continue reading “IPCC Report: Climate Change Felt On All Continents And Across The Oceans”
When soil is depleted of organic matter, water just runs off it. A rethink of farming practice is much more vital than dredging or barriers.
The Prince of Wales’s visit to the Somerset Levels has once more drawn attention to the dire circumstances faced by thousands of people because of floods. And as more extreme rain drenches the UK, calls for more flood defences and river dredging have predictably become louder. There is, however, another focus that has been hardly mentioned. It’s soil or, more specifically, the benefits we could gain by treating it better.
The way we use land has fundamentally altered the way that many of our soils work. Intensive cultivation and grazing cause massive soil loss, with sediments leaving fields to clog up watercourses. Machinery and animal hooves have also caused many soils to become compacted so that, instead of absorbing water, holding it and slowly letting it go, it runs off hard impermeable surfaces all at once.
Because of intensive farming reliant on inorganic fertilizers, there has also been a widespread reduction in the proportion of soils comprising decaying plant remains – the so-called organic matter. Soils depleted in this way hold less water than when they have a healthier proportion of once living material, thereby further altering their ability to ameliorate flood risk.
Continue reading “How To Really Stop Flooding”