Cropping System Impacts on Proton Balance and Soil Acidity In Dryland Agriculture Systems of the Palouse.

Accelerated acidification due to cropping system practices is severely impacting the current and future sustainability of Palouse cropping systems.  Intensive agriculture with its reliance on the use of ammonium (NH₄⁺)-based fertilizers and removal of alkalinity in farm products (grain and hay) is causing a significant decline in soil pH.  Currently soil pH (1:1 water) of less than 5 are commonly reported and there are virtually no local, developed sources of agricultural lime.  Proton activity is a controlling factor of soil acidity (SA) and many management and environmental drivers influence the release or consumption of protons.  Our overall objective is to more holistically evaluate cropping system impacts on soil acidification processes by using a cation/anion accounting approach that entails a systematic tracking of proton (H⁺) and hydroxyl (OH^-) generating processes that result from system cycling of C, N, and S.  Long-term studies comparing different cropping systems were evaluated including no-tillage, perennial-based and organic farming systems to assess impacts on soil acidification processes.