Benefits and Risks of Intercropping for Crop Resilience and Pest Management

Harnessing monocrop breeding strategies for intercrops

Intercropping is considered advantageous for many reasons, including increased yield stability, nutritional value and the provision of various regulating ecosystem services. However, intercropping also introduces diverse competition effects between the mixing partners, which can negatively impact their agronomic performance. Therefore, selecting complementary intercropping partners is the key to realizing a well-mixed crop production. Several specialized intercrop breeding concepts have been proposed to support the development of complementary varieties, but their practical implementation still needs to be improved. To lower this adoption threshold, we explore the potential of introducing minor adaptations to commonly used monocrop breeding strategies as an initial stepping stone towards implementing dedicated intercrop breeding schemes. While we acknowledge that recurrent selection for reciprocal mixing abilities is likely a more effective breeding paradigm to obtain genetic progress for intercrops, a well-considered adaptation of monoculture breeding strategies is far less intrusive concerning the design of the breeding programme and allows for balancing genetic gain for both monocrop and intercrop performance. The main idea is to develop compatible variety combinations by improving the monocrop performance in the two breeding pools in parallel and testing for intercrop performance in the later stages of selection. We show that the optimal stage for switching from monocrop to intercrop testing should be adapted to the specificity of the crop and the heritability of the traits involved. However, the genetic correlation between the monocrop and intercrop trait performance is the primary driver of the intercrop breeding scheme optimization process.

Biotechnological and socio-environmental potential of Campomanesia adamantium (Myrtaceae): an interdisciplinary review

Guavira (Campomanesia adamantium, Myrtaceae) is a native fruit from the Brazilian Cerrado savanna and is socio-economically important for the indigenous and traditional people living in the Central-West. This is a bibliographic review of the biological properties of guavira and its derivatives, and, after discussing experimental studies, an interdisciplinary approach is conducted highlighting the im-portance of Agroforestry Systems as an ecological restoration tool to leverage the production chain of guavira while providing ecosystem services. Many research groups studied effects of polyphenols and other bioactive compounds and biological properties of this fruit and other plant parts such as antibiotic, antioxidant, anti-inflammatory, anti-hyperlipidemic, anti-diarrheic and antitumoral activities, cardiovascular and hepatic protection and action against neuropathic pain. Besides, guavira by-products benefit poultry intestinal health, similarly to antibiotics added to their feed. Furthermore, several biotechnological products were found, like pulp flour, seasoning from the peel, sunscreen, and seed oil similar to olive oil with pharmaceutical and industrial potential. We conclude by emphasizing the importance of guavira for restoration and preservation of the threatened Brazilian Cerrado, and for the socio-environmental development of family agriculture. The same approach and study are welcome and necessary in other regions and domains worldwide having their native flora as means for a restorative end.

Assessment of molybdenum application on soybean physiological characteristics in maize-soybean intercropping

Soybean is a leguminous crop known for its efficient nitrogen utilization and ease of cultivation. However, its intercropping with maize may lead to severe reduction in its growth and yield due to shading effect of maize. This issue can be resolved by the appropriate application of essential plant nutrient such as molybdenum (Mo). Aim of this study was to assess the effect of Mo application on the morphological and physiological characteristics of soybean intercropped with maize. A two-year field experiment was conducted for this purpose, and Mo was applied in the form of sodium molybdate (Na2MoO4), and four different levels were maintained i.e., 0, 60, 120 and 180 g ha-1. Soybean exhibited varying responses to different levels of molybdenum (Mo) application. Notably, in both sole and intercropped cropping systems, the application of Mo at a rate of 120 g ha-1 demonstrated the highest level of promise compared to other application levels. However, most significant outcomes were pragmatic in soybean-maize intercropping, as application of Mo @ 120 g ha-1 significantly improved soybean growth and yield attributes, including leaf area index (LAI; 434 and 441%), total plant biomass (430 and 461%), transpiration rate (15 and 18%), stomatal conductance (9 and 11%), and yield (15 and 20%) during year 2020 and 2021 respectively, as compared to control treatment. Similarly, Mo @ 120 g ha-1 application resulted in highest total grain yield (626.0 and 725.3 kg ha-1) during 2020 and 2021 respectively, which exceeded the grain yields of other Mo levels under intercropping. Moreover, under Mo application level (120 g ha-1), grain NPK and Mo contents during years 2020 and 2021 were found to be 1.15, 0.22, 0.83 and 68.94 mg kg-1, and 1.27, 0.25, 0.90 and 72.18 mg kg-1 under intercropping system increased the value as compared to control treatment. Findings of current study highlighted the significance of Mo in enhancing soybean growth, yield, and nutrient uptake efficiency in maize-soybean intercropping systems.

Exploring the future of GM technology in sustainable local food systems in Colombia

The security of Earth's food systems is challenged by shifting regional climates. While agricultural processes are disrupted by climate change, they also play a large role in contributing to destabilizing greenhouse gases. Finding new strategies to increase yields while decreasing agricultural environmental impacts is essential. Tropical agriculture is particularly susceptible to climate change: local, smallholder farming, which provides a majority of the food supply, is high risk and has limited adaptation capacity. Rapid, inexpensive, intuitive solutions are needed, like the implementation of genetically modified (GM) crops. In the Latin American tropics, high awareness and acceptance of GM technologies, opportunities to test GM crops as part of local agricultural educations, and their known economic benefits, support their use. However, this is not all that is needed for the future of GM technologies in these areas: GM implementation must also consider environmental and social sustainability, which can be unique to a locality. Primarily from the perspective of its educators, the potential of a rural Colombian university in driving GM implementation is explored, including the role of this type of university in producing agricultural engineers who can innovate with GM to meet regionally-dependent environmental and cultural needs that could increase their sustainability.

Bio-Intensive Tactics for the Management of Invasive Fall Armyworm for Organic Maize Production

Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is an invasive pest native to the American continent. The present study focused on bio-intensive tactics like intercropping, using natural enemies, botanical insecticides and biopesticides for managing S. frugiperda for the organic production of maize in Indian conditions. A total of eight different parasitoids attacking the different stages of S. frugiperda viz., eggs and larvae were found in the study area. The total parasitism rate due to all the parasitoids ranged from 28.37 to 42.44%. The egg-larval parasitoid, Chelonus formosanus Sonan (Hymenoptera: Braconidae) was the dominant parasitoid (12.55%), followed by Chelonus nr. blackburni (Hymenoptera: Braconidae) (10.98%) and Coccygydium sp. (4.85%). About 36.58 percent of the egg masses collected was parasitized by egg parasitoids, among which Telenomus remus (Nixon) (Hymenoptera: Scelionidae) was the dominant parasitoid. The botanicals insecticides such as citronella and annona extract were most effective, resulting in 100% mortality of FAW larvae (168 h after treatment). The essential oil of garlic (100%) was found highly effective in inhibiting egg hatching, followed by geraniol (90.76%). The maize intercropped with lady's finger (okra) recorded significantly the lowest pest infestation and recorded higher grain yield (6.17 q/ha) than other intercropping systems and control (5.10 q/ha). The overall bioefficacy of commercial biopesticides against the larvae of S. frugiperda was in the following order azadirachtin > Metarhizium anisopliae (Metch.) Sorokin (Hypocreales: Clavicipitaceae) > Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Clavicipitaceae) at 168 h after treatment.

Biological control interventions reduce pest abundance and crop damage while maintaining natural enemies in sub-Saharan Africa: a meta-analysis

Insect pests are a major challenge to smallholder crop production in sub-Saharan Africa (SSA), where access to synthetic pesticides, which are linked to environmental and health risks, is often limited. Biological control interventions could offer a sustainable solution, yet an understanding of their effectiveness is lacking. We used a meta-analysis approach to investigate the effectiveness of commonly used biocontrol interventions and botanical pesticides on pest abundance (PA), crop damage (CD), crop yield (Y) and natural enemy abundance (NEA) when compared with controls with no biocontrol and with synthetic pesticides. We also evaluated whether the magnitude of biocontrol effectiveness was affected by type of biocontrol intervention, crop type, pest taxon, farm type and landscape configuration. Overall, from 99 studies on 31 crops, we found that compared to no biocontrol, biocontrol interventions reduced PA by 63%, CD by over 50% and increased Y by over 60%. Compared to synthetic pesticides, biocontrol resulted in comparable PA and Y, while NEA was 43% greater. Our results also highlighted that the potential for biocontrol to be modulated by landscape configuration is a critical knowledge gap in SSA. We show that biocontrol represents an effective tool for smallholder farmers, which can maintain yields without associated negative pesticide effects. Furthermore, the evidence presented here advocates strongly for including biocontrol practices in national and regional agricultural policies.

Introduction to the Collection: Climate Change, Insect Pests, and Beneficial Arthropods in Production Systems

Climate change is expected to alter pressure from insect pests and the abundance and effectiveness of insect pollinators across diverse agriculture and forestry systems. In response to warming, insects are undergoing or are projected to undergo shifts in their geographic ranges, voltinism, abundance, and phenology. Drivers include direct effects on the focal insects and indirect effects mediated by their interactions with species at higher or lower trophic levels. These climate-driven effects are complex and variable, sometimes increasing pest pressure or reducing pollination and sometimes with opposite effects depending on climatic baseline conditions and the interplay of these drivers. This special collection includes several papers illustrative of these biological effects on pests and pollinators. In addition, in response to or anticipating climate change, producers are modifying production systems by introducing more or different crops into rotations or as cover crops or intercrops or changing crop varieties, with potentially substantial effects on associated insect communities, an aspect of climate change that is relatively understudied. This collection includes several papers illustrating these indirect production system-level effects. Together, biological and management-related effects on insects comprise the necessary scope for anticipating and responding to the effects of climate change on insects in agriculture and forest systems.