Crops & Soils

Biochar and Basalt Dust Interactions – Thomas Goreau, Global Coral Reef Alliance http://www.youtube.com/watch?v=Vw8_4zBnNdQ Biochar and rock dusts such as basalt are widely regarded as excellent slow-release, long-lasting, natural fertilizers by themselves, which should work even better in combination. But there are few studies of their interactions or optimal combinations. A long-term study of biochar and basalt dust interactions in 32 plots, using combinations of 3 levels of biochar and 4 levels of basalt dust, with replicates and controls is underway at New Harmony Farm, in West Newbury, Massachusetts. Because the benefits of both basalt dust and biochar become greatest after several years, long term changes in crop yields, elemental composition of soil and crops, carbon storage, and greenhouse gas emissions will be measured. The first crop of beets and radishes showed very strong stimulation of plant productivity (measured as total fresh weight per plant at harvest) by basalt powder, up to 2.5 times greater for beet and 2.2 times for radish. We found inhibition of beet and radish yields by biochar in the first crop, probably due to nutrient immobilization caused by the high C/N ratio. Basalt powder was observed to strongly increase earthworm activity. The inhibitory effect of biochar disappeared by the second crop of radishes, which was sown late and affected by early frost. This is presumably because the microbial flora associated with the biochar and rock powder became more mature, and as base cations from basalt weathering are taken up on biochar cation exchange sites. Preliminary data showed reduced greenhouse gas emissions in biochar and basalt powder treated plots compared to controls. We expect that the agricultural productivity, crop nutritional quality, soil carbon storage, and greenhouse gas emissions will evolve as biochar and basalt powder continue to mature and interact. The long-term results will provide useful guidelines for managing biochar/rock dust combinations to optimize economic, environmental, ecological, and climate change benefits. Biochar & Meat Bone Meal Impact on Soils – Priit Tammeorg, University of Helsinki Poor water retention and nutrient deficiency commonly limit crop yields in sandy soils and biochar (BC) use as a soil conditioner has been previously reported to improve these limiting factors in subtropical and temperate soils. We studied the effects of BC on soil properties, earthworm density and biomass and spring wheat yield formation when applied together with mineral fertiliser or meat bone meal (MBM) to an Endogleyic Umbrisol with a loamy sand texture in boreal conditions. In a two-year field experiment conducted in Helsinki, Finland, biochar was applied at rates 0, 5, 10, 20 and 30 t ha-1 with three fertiliser treatments (unfertilised control, MBM and mineral fertiliser). The soil moisture content, the leaf area index and the relative leaf chlorophyll content were monitored during the experiment. Additionally, soil water holding capacity (WHC), soil fertility, earthworm density as well as grain yield, its quality and yield components were analysed. BC increased the WHC and the available water content of the soil in the first year and reduced bulk density and increased porosity in the second year after application. BC application increased also the contents of easily soluble K and total C in soil but had only insignificant effects on other soil nutrients, pH, moisture content or density and biomass of earthworms. Interestingly, the highest BC addition decreased the soil NO3-N content over the control in first year, and increased it significantly on the second year. BC application did not affect significantly the wheat yield formation, grain yield or the quality of it in any year. Our results suggest that BC has a potential in increasing the contents of water, C and K in soil and can consequently relieve K deficiency and mild drought stress of plants when applied to loamy sand in a boreal climate with MBM or mineral fertiliser. Furthermore, BC use as a soil amendment does not bring about immediate earthworm avoidance reactions under field conditions. The follow-up of the experiment should be continued in order to investigate longer term effects in soil and plant properties. Research conducted by: Priit Tammeorga, Asko Simojokib, Frederick L. Stoddarda, Tuure Parviainena, Visa Nuutinenc, Pirjo Mäkeläa, Elina Vaarab, Laura Alakukkud, Juha Heleniusa aDepartment of Agricultural Sciences, P.O. Box 27 (Latokartanonkaari 5, Plant Production Sciences), FIN-00014 University of Helsinki, Finland. bDepartment of Food and Environmental Sciences, P.O. Box 27 (Latokartanonkaari 11, Environmental Soil Science), FIN-00014 University of Helsinki, Finland cMTT Agrifood Research Finland, Plant Production, FIN-31600 Jokioinen, Finland. dDepartment of Agricultural Sciences, P.O. Box 28 (Koetilantie 5, Agrotechnology), FIN-00014 University of Helsinki, Finland. Removing nutrients from agricultural runoff and returning them to the land: Kirk Jones, Whole Farm Systems Water bodies around the world are suffering from too many nutrients while farmers struggle to keep their nutrients on their soil. Working with Shelburne Farm’s Vermont dairy to preserve the precious resource of Lake Champlain, we tested the effectiveness of using various media to retain phosphorus, ammonium, and E. coli in a simulated agricultural runoff environment. Eleven initial media were screened for elemental content, phosphorus sorption and pH. Media were judged for sorption by mass and by time. Phosphorus adsorption isotherms were plotted for softwood biochar, activated carbon and coral sand. Pyrolysis effects on nitrogen and phosphorus in biochar are discussed along with nutrient availability in soils. The aim is to develop a nutrient and carbon sequestering runoff filtration media that can enhance crop yields and support long term soil health