A global meta-analysis of yield stability in organic and conservation agriculture

Abstract

One of the primary challenges of our time is to enhance global food production and security. Most assessments in agricultural systems focus on plant yield. Yet, these analyses neglect temporal yield stability, or the variability and reliability of production across years. Here we perform a meta-analysis to assess temporal yield stability of three major cropping systems: organic agriculture and conservation agriculture (no-tillage) vs. conventional agriculture, comparing 193 studies based on 2896 comparisons. Organic agriculture has, per unit yield, a significantly lower temporal stability (−15%) compared to conventional agriculture. Thus, although organic farming promotes biodiversity and is generally more environmentally friendly, future efforts should focus on reducing its yield variability. Our analysis further indicates that the use of green manure and enhanced fertilisation can reduce the yield stability gap between organic and conventional agriculture. The temporal stability (−3%) of no-tillage does not differ significantly from those of conventional tillage indicating that a transition to no-tillage does not affect yield stability.

Processing Tomato–Durum Wheat Rotation under Integrated, Organic and Mulch-Based No-Tillage Organic Systems: Yield, N Balance and N Loss

“…The adoption of TIC in ORG+ considerably improved the N self-sufficiency of this system [31], raising (+35%) the Ndfa as compared to ORG. As expected, the Noutput values confirmed the gap between organic and conventional farming systems [32]; the Noutput values observed in ORG+ were the lowest in accordance with the finding of Knapp and van der Heijden [33] and Cooper et al [34]. Nsurplus was high in both INT and ORG+, but such effects resulted from different reasons: in INT, there was a very high Ninput and a high Noutput, while in ORG+ there was high Ninput coupled with low Noutput.…”

Responses of the Terrestrial Ecosystem Productivity to Droughts in China

“…This is because in the CASA model, factors involving agricultural productions (e.g., fertilization, agricultural management, and irrigation) have been excluded. In fact, these factors play an important role in promoting agricultural yield (Knapp and van der Heijden, 2018). Compared to other studies, our derived NPPs for evergreen broad-leaf forest and deciduous needle-leaf forest are very similar to observed NPP.…”

Organic Farming Provides Reliable Environmental Benefits but Increases Variability in Crop Yields: A Global Meta-Analysis

“…We hypothesize that organic farms will have lower yields as well as greater variability in yield over time compared to conventional farms (Knapp and van der Heijden, 2018). This is because organic farms are more reliant on ecosystem services for production of high crop yields, whereas conventional farms can rely more heavily on external inputs (Reganold and Wachter, 2016).…”