40 Years of Organic Green Manure for the Win

A new study finds:

  • Organic Green Manure and Organic Animal Manure treatments increased cumulative water infiltration by about 10 times compared with the conventional farming treatment
  • Soil aggregates increased by 50% with the Organic Green Manure and by 30% with the Organic Animal Manure treatments in the upper 15-cm depth
  • At the same depth, bulk density was 3% lower under organic practices than in the conventional farming treatment, suggesting that organic farming reduces the soil’s susceptibility to compaction.

Organic Farming and Soil Physical Properties: An Assessment after 40 Years

Continuous Monocropping.

A new study using a LARGE dataset has found for corn and soybean:

  • Analysis of 748,374 yield records showed a 4.3% yield penalty for continuous corn.
  • Corn yield penalties were more severe in areas with low moisture and low yields.
  • Continuous soybean showed a 10.3% yield penalty, worse in low-yielding years.
  • Corn yield penalties grew with up to 3 yr of continuous cropping, but not more.
  • Soybean penalties increased monotonically with number of years continuously cropped.

Continuous Corn and Soybean Yield Penalties across Hundreds of Thousands of Fields

 

Cover Crops May Increase Soil Microbial Biomass 3x More Than Compost

Three to six times more microbial biomass carbon and nitrogen depending on soil type.

These results provide evidence that carbon (C) inputs from frequent cover cropping are the primary driver of changes in the soil food web and soil health in high-input, tillage-intensive organic vegetable production systems.

Fresh is best.

Cover cropping frequency is the main driver of soil microbial changes during six years of organic vegetable production

New Slow-release Nitrogen Calcium Phosphate Fertilizer

ureaca

Researchers have used nanoparticles to create a a fertilizer that releases nutrients over a week, giving crops more time to absorb them (ACS Nano 2017, DOI: 10.1021/acsnano.6b07781).

They attached urea molecules to nanoparticles of hydroxyapatite, a naturally occurring form of calcium phosphate found in bone meal. Hydroxyapatite is nontoxic and a good source of phosphorous, which plants also need.

In water, the urea-hydroxyapatite combination released nitrogen for about a week, compared with a few minutes for urea by itself. In field trials on rice in Sri Lanka, crop yields increased by 10%, even though the nanofertilizer delivered only half the amount of urea compared with traditional fertilizer.

Slow-release nitrogen fertilizer could increase crop yields | Chemical & Engineering News http://cen.acs.org/articles/95/web/2017/02/Slow-release-nitrogen-fertilizer-increase.html

They should call it UreaCa! Geddit?

Alternately you could just use fresh plant litter or cover crop residues that leach nitrogen over two weeks and also feed soil microbes carbon. Or faba bean that will release it over three years[1] and build soil carbon so eventually you don’t need to add any.

[1] Carbon and Nitrogen Release from Legume Crop Residues for Three Subsequent Crops
Abstract | Digital Library https://dl.sciencesocieties.org/publications/sssaj/abstracts/79/6/1650

[2] Formation of soil organic matter via biochemical and physical pathways of litter mass loss : Nature Geoscience : Nature Research http://www.nature.com/ngeo/journal/v8/n10/full/ngeo2520.html