I believe improved crop practices are a vital aspect in meeting our cellulosic feedstock needs. There are a few areas that offer significant potential:
- crop rotation,
- the use of polyculture plantations,
- perennials as energy crops, and
- better agronomic practices.
We address all four issues here. Though none of these have been extensively studied, early studies and knowledgeable speculation point to their likely utility. Further study of these techniques is urgently needed, especially the use of grasses or other biomass-optimized winter cover crops.
Crop rotation
I have proposed the usage of a 10 year x 10 year energy and row crop rotation. As row crops are grown in the usual corn/soy rotation, lands lose topsoil and get degraded, need increased fertilizer and water inputs, and decline in biodiversity. By growing no-till, deep-rooted perennial energy crops (like miscanthus or switchgrass -- see below) for ten years following a ten year row crop cycle, the carbon content of the soil and its biodiversity can be improved and the needs for inputs decreased. The land can then be returned to row crop cultivation after ten years of no-till energy crops.
Currently unusable degraded lands may even be reclaimed for agriculture using these techniques over a few decades. A University of North Dakota study highlights some of the benefits for food crops. I expect similar or even greater benefits for food crop/energy crop long cycle rotations, especially in soil carbon content: