Premium
Opposing effects of different soil organic matter fractions on crop yields
Author(s) -
Wood Stephen A.,
Sokol Noah,
Bell Colin W.,
Bradford Mark A.,
Naeem Shahid,
Wallenstein Matthew D.,
Palm Cheryl A.
Publication year - 2016
Publication title -
ecological applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.864
H-Index - 213
eISSN - 1939-5582
pISSN - 1051-0761
DOI - 10.1890/16-0024.1
Subject(s) - organic matter , environmental science , nutrient cycle , cycling , soil organic matter , agroecosystem , nutrient , agronomy , soil water , agriculture , ecology , soil science , biology , archaeology , history
Soil organic matter is critical to sustainable agriculture because it provides nutrients to crops as it decomposes and increases nutrient‐ and water‐holding capacity when built up. Fast‐ and slow‐cycling fractions of soil organic matter can have different impacts on crop production because fast‐cycling fractions rapidly release nutrients for short‐term plant growth and slow‐cycling fractions bind nutrients that mineralize slowly and build up water‐holding capacity. We explored the controls on these fractions in a tropical agroecosystem and their relationship to crop yields. We performed physical fractionation of soil organic matter from 48 farms and plots in western Kenya. We found that fast‐cycling, particulate organic matter was positively related to crop yields, but did not have a strong effect, while slower‐cycling, mineral‐associated organic matter was negatively related to yields. Our finding that slower‐cycling organic matter was negatively related to yield points to a need to revise the view that stabilization of organic matter positively impacts food security. Our results support a new paradigm that different soil organic matter fractions are controlled by different mechanisms, potentially leading to different relationships with management outcomes, like crop yield. Effectively managing soils for sustainable agriculture requires quantifying the effects of specific organic matter fractions on these outcomes.