Friends or foes? Population dynamics of beneficial and detrimental aerial arthropods under Conservation Agriculture

Mhlanga, Blessing; Muoni, Tarirai; Mashavakure, Nilton; Mudadirwa, Derek; Mulenga, Rabson M.; Sitali, Mwangala; Thierfelder, Christian

doi:10.1016/j.biocontrol.2020.104312

Cited by 8 publications

(4 citation statements)

References 36 publications

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“…No-tillage and crop residue retention encourage soil life and microbial activity benefiting both above and below ground biodiversity (Mashavakure et al, 2019; Mhlanga et al, 2020; Muoni et al, 2019). Research by Muoni et al (2019) and Thierfelder and Wall (2010) confirmed that no-tillage with residue cover significantly increases the abundance of earthworms which are most important to develop a conducive soil pore structure (Kladviko, Griffith and Mannering, 1986a; Kladviko, Mackay and Bradford, 1986b).…”

Section: The Issue Of Residue Retention In Mixed Crop/livestock Systemsmentioning

confidence: 99%

Unanswered questions and unquestioned answers: the challenges of crop residue retention and weed control in Conservation Agriculture systems of southern Africa

Thierfelder,

Mhlanga,

Ngoma

et al. 2024

Renew. Agric. Food Syst.

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Production and utilization of crop residues as mulch and effective weed management are two central elements in the successful implementation of Conservation Agriculture (CA) systems in southern Africa. Yet, the challenges of crop residue availability for mulch or the difficulties in managing weed proliferation in CA systems are bigger than a micro-level focus on weeds and crop residues themselves. The bottlenecks are symptoms of broader systemic complications that cannot be resolved without appreciating the interactions between the current scientific understanding of CA and its application in smallholder systems, private incentives, social norms, institutions, and government policy. In this paper, we elucidate a series of areas that represent some unquestioned answers about chemical weed control and unanswered questions about how to maintain groundcover demanding more research along the natural and social sciences continuum. In some communities, traditional rules that allow free-range grazing of livestock after harvesting present a barrier in surface crop residue management. On the other hand, many of the communities either burn, remove, or incorporate the residues into the soil thus hindering the near-permanent soil cover required in CA systems. The lack of soil cover also means that weed management through soil mulch is unachievable. Herbicides are often a successful stopgap solution to weed control, but they are costly, and most farmers do not use them as recommended, which reduces efficacy. Besides, the use of herbicides can cause environmental hazards and may affect human health. Here, we suggest further assessment of the manipulation of crop competition, the use of vigorously growing cover crops, exploration of allelopathy, and use of microorganisms in managing weeds and reducing seed production to deplete the soil weed seed bank. We also suggest in situ production of plant biomass, use of unpalatable species for mulch generation and change of grazing by-laws towards a holistic management of pastures to reduce the competition for crop residues. However, these depend on the socio-economic status dynamics at farmer and community level.

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Section: The Issue Of Residue Retention In Mixed Crop/livestock Systemsmentioning

confidence: 99%

Unanswered questions and unquestioned answers: the challenges of crop residue retention and weed control in Conservation Agriculture systems of southern Africa

Thierfelder,

Mhlanga,

Ngoma

et al. 2024

Renew. Agric. Food Syst.

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“…Improved soil health may also aid in decreasing insect pests, weeds, and disease incidences through improved biological control. It may help in minimizing rates of population buildup of insect pest species, through disruption of the life cycle in the absence of host plant (Dumanski et al, 2006;Kassam et al, 2009), releasing secondary metabolites, and enhancing the biodiversity of beneficial insects and thus improved biological control of pests (Mhlanga et al, 2020).…”

Section: Diversified Crop Rotationmentioning

confidence: 99%

“…Contrarily, planting crops using conventional tillage has been reported to disturb arthropod habitats, and disrupt their life cycle resulting in reduced biological activity (Mhlanga et al, 2020). Agronomic crop management using conventional or CA practices is presumably may lead to shifts in diversity as well as the abundance of insect pests due to changes in their habitats (Jasrotia et al, 2021;Wilson and Fox, 2021).…”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, more diverse systems (e.g., crop residue retention, mixed cropping, intercropping, and cover cropping) can result in higher niche diversification and provide the predators with shelter and hunting ground (Mashavakure et al, 2019b;Feng et al, 2023). Thus, increased biological activity in CA systems may encourage the emergence of new pest species while also favoring the natural enemies of these pests (Mhlanga et al, 2020). Under CA, both positive and negative shifts in pest attacks, damage, and crop yield consequences have been documented (Chabert and Sarthou, 2020;Kumar et al, 2022).…”

Section: Introductionmentioning

confidence: 99%

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Conservation agriculture based crop management practices impact diversity and population dynamics of the insect-pests and their natural enemies in agroecosystems

Jasrotia

Kumari

Malik

et al. 2023

Front. Sustain. Food Syst.

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Human efforts to grow abundant food through the persistent use of resource-intensive farming practices have resulted in declining soil health, and deterioration of ecosystem functions and services. Conservation agriculture (CA) has emerged as a practice to minimize the impacts of conventional resource-exhaustive and energy-intensive agriculture. Minimum soil disturbance, permanent soil cover, and diversification are the key components of CA. Tillage through conventional practices on the other hand has detrimental effects on the soil and environment as it requires deep inversion of soil with instruments such as mouldboard plow, disc plow etc. leaving very less organic matter in soil after establishment of crop. Even though, CA advocates many benefits over conventional agriculture in terms of soil and water conservation, the consequent changes in moisture and temperature regimes due to reduced tillage and surface cover would likely going to influence the biological activity, including insect pests and their natural enemies which dwell within these agroecosystems. The changed crop conditions under CA may favor particular insect communities and their ecological niches. The adoption of such practices may lead to decrease in insect pests with major activity on the crop canopy. However, the activity of the insect pests that spend their maximum life span at the soil surface or beneath the soil surface may increase. Recent insect-pest outbreaks in North-Western India and imbalances reported in Indo-Gangetic Plains point to the need for a better understanding of the inter-relationships between tillage intensity, residue retention, and insect pest population dynamics. The current review analyzes the existing state of knowledge of these dynamics and presents the scenarios that may emerge as CA get more acceptance. This review will help to develop countermeasures to improve performance and ecosystem services of Conservation agriculture (CA) based cropping systems.

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Management of maize-legume conservation agriculture systems rather than varietal choice fosters human nutrition in Malawi

Muoni,

Mhlanga,

Öborn

et al. 2024

Food Sec.

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Malawi smallholder farmers are facing climate-induced challenges that have increased food and nutrition insecurity in the country, thus sustainable intensification practices has been widely recommended. The objective of this study was to assess the effects of cropping systems with improved varieties on total system productivity and nutrition under different environments. The study involved on-farm experiments in ten communities in Central and Southern Malawi, incrementally established from 2005/2006 to 2018/2019 cropping seasons. Each community had six demonstration plots with three main treatments: conventional ploughing (CP): sole maize grown on seasonally constructed ridges and furrows; no-tillage (NT): sole maize grown on retained ridges with minimum soil disturbance and residue retained; and Conservation agriculture (CA): maize intercropped either cowpea, pigeon pea or groundnut on retained ridges as in NT. Our results show that total system nutrition was higher in CA treatments than NT and CP. The yields of maize were at least 800 kg ha−1 higher in CA and NT than CP despite the variety that was grown. Legume yields were also higher under CA and NT than CP. High protein yield was observed in CA systems (at least 100 kg ha−1 higher than CP) where maize and legume intercrops were rotated with grain legumes. Our results show nutrients and energy gains in CA and NT systems that can be invested in practices that increases the resilience of smallholder farmers to climate change. Conservation agriculture and NT systems have more influence on productivity of smallholder farms, despite the genotypes used (hybrids or OPVs).

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Friends or foes? Population dynamics of beneficial and detrimental aerial arthropods under Conservation Agriculture

Cited by 8 publications

References 36 publications

Unanswered questions and unquestioned answers: the challenges of crop residue retention and weed control in Conservation Agriculture systems of southern Africa

Unanswered questions and unquestioned answers: the challenges of crop residue retention and weed control in Conservation Agriculture systems of southern Africa

Conservation agriculture based crop management practices impact diversity and population dynamics of the insect-pests and their natural enemies in agroecosystems

Management of maize-legume conservation agriculture systems rather than varietal choice fosters human nutrition in Malawi

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