|Scooped by Jim Hall|
Biochar Investment for Drought-Proofing Soil
Biochar is usually thought of as a soil amendment, similar to compost or lime. But unlike most soil amendments, biochar is stable in soil and it accumulates when more is added every year.
Biochar has been shown to increase the water holding capacity (WHC) of soil in a linear fashion – the more biochar you add, the more water the soil will hold. In this sense, biochar could be seen as a capital investment in soil infrastructure.
In regions like California where drought can be severe and is increasing with climate change, biochar should be part of a package of agricultural infrastructure investments that includes precision irrigation systems. Taken together, more efficient irrigation and biochar may allow fields and orchards to survive periods of very low water availability.
Biochar has many other advantages over alternative drought measures:
1. Unlike an irrigation system, biochar requires no annual maintenance.
2. Biochar also increases the water use efficiency (WUE) of plants because it encourages the growth of roots and root symbionts such as mycorrhizal fungi.
3. Biochar relieves soil salinity by several mechanisms including the binding of salts.
4. Additionally, biochar improves soil nutrient retention and uptake by plants.
5. Biochar can also induce systemic plant resistance to disease and infection.
6. Biochar promotes humification of soil organic matter, so its benefits increase over time.
The State of California is taking various measures to address the severe drought of 2014. One measure will be grants and subsidies to farmers to improve water delivery systems. But this only addresses the challenge of efficiently getting the reduced water allocation to the field. Better use of water in the field can only be addressed through soil additives like compost or biochar. Compost is helpful, but it must be reapplied with every crop.
An economic return analysis would reveal that biochar pays for itself rather quickly as a drought-proofing measure. Done on a large scale, biochar could help save California agriculture. The cost of applying biochar strategically over time will likely be comparable to the cost of upgrading irrigation systems. Without biochar, more efficient water delivery alone will not be enough to compensate for the reduction in water allocations, now and in the future.
Wilson Biochar Associates
Posted on Facebook by Michael Whittman from Blue Sky Biochar.