Conservation agriculture enhances resistance of maize to climate stress in a Malawian medium-term trial

AbstractMacro-organisms contribute significantly to soil fertility improvement. The influence of conservation agriculture (CA) in southern Africa on their populations has not yet been fully understood. Thus, the objective of the current study was to evaluate the effects of CA and conventional tillage on below ground biological activity in a CA long-term trial in Monze, Zambia from 2011 to 2013. The study had ten treatments which differed by tillage systems (conventional ploughing, planting basins and direct seeding) and crop diversification intensity (sole cropping, 2- or 3-year crop rotations) involving maize, cotton and sunn hemp. These factors were combined to create rotation-tillage (RotTill) treatments. Sampling of macrofauna was done once per year using a metal frame measuring 0.25 m2, hand-sorted to 30-cm depth. RotTill treatments had a significant effect on earthworms (Lumbricus terrestris), termites (Coptotermes formosanus), dung beetles (Scarabaeus viettei) and centipedes (Lithobius forficatus). Earthworms and termites were more abundant in CA treatments than in conventionally ploughed (CP) treatments. Biota diversity was generally higher in CA treatments than in CP controls. Conventional mouldboard ploughing generally reduced macrofauna, thus affecting biological soil fertility and the beneficial effect of the interactions of these organisms with the soil. CA treatments had the highest maize grain yields throughout the study period. Based on the results, reduced tillage systems and crop rotations increase biological activity shown by increased densities of termites and earthworms.

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Rotation, Mulch and Zero Tillage Reduce Weeds in a Long-Term Conservation Agriculture Trial

Agronomy ◽

10.3390/agronomy10070962 ◽

2020 ◽

Vol 10 (7) ◽

pp. 962

Author(s):

Simon Fonteyne ◽

Ravi Gopal Singh ◽

Bram Govaerts ◽

Nele Verhulst

Keyword(s):

Weed Management ◽

Conservation Agriculture ◽

Conventional Tillage ◽

Weed Species ◽

Weed Biomass ◽

Perennial Weeds ◽

Term Trial ◽

Density And Biomass ◽

Three Components

Weed management is one of the main challenges of conservation agriculture. Although all three components of conservation agriculture (minimal tillage, permanent soil cover and crop diversification) can reduce weed populations, these effects may only become apparent in the medium to long term. This study evaluated weed biomass, density and diversity with and without herbicide control in a long-term trial initiated in 1991 in the Mexican Highlands to evaluate all three components of conservation agriculture. Data were collected in 2004, 2005, 2013, 2014 and 2015. Weed density and biomass were generally lower in conservation agriculture than with conventional tillage. The three components of conservation agriculture significantly reduced weed biomass, which was lower when all three components were applied together. When herbicides were applied, weed biomass in conservation agriculture was 91% lower in maize and 81% lower in wheat than in conventional tillage. Different treatments favored different weed species, but no trend toward increased perennial weeds was observed in conservation agriculture. These data supported claims stating that if adequate weed control is achieved in the initial years, weed populations in conservation agriculture systems are lower than in conventional tillage systems.

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