Intercropping is a farming practice involving two or more crop species, or genotypes, growing together and coexisting for a time. On the fringes of modern intensive agriculture, intercropping is ...important in many subsistence or low‐input/resource‐limited agricultural systems. By allowing genuine yield gains without increased inputs, or greater stability of yield with decreased inputs, intercropping could be one route to delivering ‘sustainable intensification’. We discuss how recent knowledge from agronomy, plant physiology and ecology can be combined with the aim of improving intercropping systems. Recent advances in agronomy and plant physiology include better understanding of the mechanisms of interactions between crop genotypes and species – for example, enhanced resource availability through niche complementarity. Ecological advances include better understanding of the context‐dependency of interactions, the mechanisms behind disease and pest avoidance, the links between above‐ and below‐ground systems, and the role of microtopographic variation in coexistence. This improved understanding can guide approaches for improving intercropping systems, including breeding crops for intercropping. Although such advances can help to improve intercropping systems, we suggest that other topics also need addressing. These include better assessment of the wider benefits of intercropping in terms of multiple ecosystem services, collaboration with agricultural engineering, and more effective interdisciplinary research.
Aims
Intercropping cereals with legumes may achieve high crop yields at reduced input levels. Several studies have indicated that intercropping increases phosphorus use efficiency but no overarching ...analysis exists on the role of species traits and input levels. Here we synthesize the available information on P use efficiency in cereal/legume intercropping.
Methods
Global data on yields, P uptake and nutrient input in cereal/legume mixtures were extracted from the literature and statistically analyzed. Co-variables explaining P uptake efficiency and yield were considered.
Results
P uptake was substantially increased with an average value of LER
P
, the land equivalent ratio for P uptake, of 1.24, and an average NE
P
(observed P uptake minus expected P uptake) of 3.67 kg P ha
−1
. The conversion efficiency of P uptake to biomass decreased with P uptake and was lower in intercrops than in sole crops but the conversion efficiency to yield was not affected by intercropping. The P fertilizer requirement was 21% lower in intercrops than in sole crops for the same yields.
Conclusions
Substantial improvements in land use efficiency and P uptake are obtained by cereal/legume intercropping. Cereal/legume intercropping has therefore potential to increase P fertilizer use efficiency in agriculture.
•Interspecific water competition existed between rubber trees and intercrops.•Observed water uptake complementarity differed from that of previous reports.•Intercrops could promote surface soil water ...availability for rubber trees.•Facilitative effects were most marked in rubber-galangal agroforestry.
Despite the development of rubber agroforestry systems for ecological and economic benefits in Southeast Asia, knowledge of their water uptake dynamics and interspecific water interactions remains limited. The objective of this study is to reveal the water relations (i.e., competition/complementarity) between rubber (Hevea brasiliensis) trees and different kinds of intercrops. We investigated the stable isotopes (δD and δ18O), fine root length density, and soil water content (SWC) under three agroforestry practices and one rubber monoculture across a year (2017/2018). Our results indicated that rubber trees acquired more than 40.5 ± 21.3 % of their water from shallow (0−20 cm) soil stratum, as do perennial galangal (Alpinia officinarum), tea (Camellia sinensis), and cocoa (Theobroma cacao). The complementarity hypothesis was not supported for rubber trees and the intercrops. In the dry season (November to April), there was strong interspecific competition for shallow water resources where the intercropping was practiced. However, intercropping increased the available soil water, enabling rubber trees to acquire more (9.4–24.3 %) shallow soil water. In the wet season (May to October), interspecific water competition was less pronounced based on the relative difference in soil water content (RDSW). Higher relative water content, in the order rubber-galangal > rubber-tea > rubber-cocoa, further showed that facilitative effects dominated interspecific water competition in all the agroforestry practices. This information regarding water relations between rubber trees and their intercrops will be essential to optimize land and water resource utilization in this region.
Facilitation takes place when plants ameliorate the environment of their neighbours, and increase their growth and survival. Facilitation occurs in natural ecosystems as well as in agroecosystems. We ...discuss examples of facilitative root interactions in intercropped agroecosystems; including nitrogen transfer between legumes and non-leguminous plants, exploitation of the soil via mycorrhizal fungi and soil-plant processes which alter the mobilisation of plant growth resources such as through exudation of amino acids, extra-cellular enzymes, acidification, competition-induced modification of root architecture, exudation of growth stimulating substances, and biofumigation. Facilitative root interactions are most likely to be of importance in nutrient poor soils and in low-input agroecosystems due to critical interspecific competition for plant growth factors. However, studies from more intensified cropping systems using chemical and mechanical inputs also show that facilitative interactions definitely can be of significance. It is concluded that a better understanding of the mechanisms behind facilitative interactions may allow us to benefit more from these phenomena in agriculture and environmental management.
Fall armyworm (FAW) is a multi-generational invasive insect pest of maize. Field experiments were conducted in diverse ecologies at Hyderabad, Telangana (Location 1); Dholi, Bihar (Location 2); ...Kolhapur, Maharashtra (Location 3) during the rainy season from July-November, 2023 to assess the impact of maize intercropping with legumes and leafy vegetables on FAW damage, abundance of beneficial insects, weed dynamics, and yield. In the present study, location-specific intercrops were selected for the experimentation. In location 1, maize intercropped with cowpea followed by groundnut reduced the level of FAW infestation compared to sole maize. The increased natural enemy population (coccinellids, spiders, earwigs); weed suppression, and higher yields were observed in maize when intercropped with cowpea followed by groundnut and red amaranthus. In location 2, maize intercropped with cowpea followed by green gram and black gram reduced the FAW damage and higher natural enemy population. Maximum yield was obtained in maize intercropped with black gram followed by green gram and cowpea. However, concerning weed suppression and cost-benefit ratio, green gram followed by black gram was found to be superior. Minimum FAW infestation, abundant natural enemy population, weed suppression, and improved economic returns were observed in maize when intercropped with cowpea followed by groundnut and fenugreek in location 3. Each intercrop had its advantages concerning pests, weed suppression, an abundance of natural enemy populations, and higher yields. Therefore, it is suggested that the selection of plants as intercrops with maize should be based on the location-specific importance of particular aspects to attain multifunctional benefits. The present results revealed that crop diversification with location-specific intercrops can reduce significant yield losses caused by FAW and promote higher yields in maize.
Display omitted
•Location-specific intercropping in maize reduced FAW damage as compared to sole maize.•Plant diversity increased the natural enemy population such as coccinellids, spiders and earwigs of FAW.•Growing intercrops in maize resulted in weed suppression as the intercrops increase the competition for light.•Improved maize yield and higher benefit-cost ratio were obtained with location-specific intercrops in maize.
Biodiversity can support a greener revolution in Africa Snapp, Sieglinde S.; Blackie, Malcolm J.; Gilbert, Robert A. ...
Proceedings of the National Academy of Sciences - PNAS,
11/2010, Letnik:
107, Številka:
48
Journal Article
Recenzirano
Odprti dostop
The Asian green revolution trebled grain yields through agro-chemical intensification of monocultures. Associated environmental costs have subsequently emerged. A rapidly changing world necessitates ...sustainability principles be developed to reinvent these technologies and test them at scale. The need is particularly urgent in Africa, where ecosystems are degrading and crop yields have stagnated. An unprecedented opportunity to reverse this trend is unfolding in Malawi, where a 90% subsidy has ensured access to fertilization and improved maize seed, with substantive gains in productivity for millions of farmers. To test if economic and ecological sustainability could be improved, we preformed manipulative experimentation with crop diversity in a countrywide trial (n = 991) and at adaptive, local scales through a decade of participatory research (n = 146). Spatial and temporal treatments compared monoculture maize with legume-diversified maize that included annual and semiperennial (SP) growth habits in temporal and spatial combinations, including rotation, SP rotation, intercrop, and SP intercrop systems. Modest fertilizer intensification doubled grain yield compared with monoculture maize. Biodiversity improved ecosystem function further: SP rotation systems at half-fertilizer rates produced equivalent quantities of grain, on a more stable basis (yield variability reduced from 22% to 13%) compared with monoculture. Across sites, profitability and farmer preference matched: SP rotations provided twofold superior returns, whereas diversification of maize with annual legumes provided more modest returns. In this study, we provide evidence that in Africa, crop diversification can be effective at a countrywide scale, and that shrubby, grain legumes can enhance environmental and food security.
Intercropping ensures multiple benefits like enhancement of yield, environmental security, production sustainability, and greater ecosystem services. In order to better understand how mixed crop ...cultures mitigate stressful conditions, this study aims to highlight the beneficial effect of the intercropping legume-cereal in enhancing nutrient uptake for plant growth and productivity in low phosphorus (P) soils. To address this question, faba bean (Vicia faba L. cv. Sidi Aich) and barley (Hordeum vulgare L. cv. Rihane 3) were grown as sole- and inter-crops over two growing seasons in 2017 and 2018 in a northern Algerian agro-ecosystem with a semiarid Mediterranean climate. The results showed that the plant growth and nodulation were significantly increased by 18% and 32%, respectively, for intercropping than for sole cropping and so more in 2018 compared to 2017. Moreover, grain yield and resource use efficiency (N and P) were significantly improved, as indicated by higher land equivalent ratio (LER > 1) in intercropping over sole cropping treatments. Also, the P and N concentrations measured in the rhizosphere were increased compared to bulk soil and even more so in the rhizosphere of intercropped species over two seasons. Our findings suggest that intercropping cereals with legumes may achieve high crop productivity and land use efficiency at reduced input levels.
•The n-dimensional hypervolumes and multivariate analysis revealed differences in plant species performances in sole crops and intercrops.•The changes in hypervolumes resulted from the plasticity of ...plant phenotypic traits.•High trait values were associated with small plant trait variability under more productive conditions.
The relevance of intercropping, where two or more crop species are simultaneously grown on the same land space, is growing due to its potential for improving resource use and maintaining stable yields under variable weather conditions. However, the actual growth of intercropped species may differ resulting from the idiosyncratic effect of crop diversity, and with this, the realized benefits from intercrops are found to depend critically on the cultivar, species, management and environmental conditions. This study aimed to apply a trait-based approach, in which ecological niche spaces are defined through n-dimensional hypervolumes, to identify the contribution of species/cultivar, cultivation design (sole crop or intercrop) and management (low or high fertilization) to the trait diversity of four crop species, pea-barley and faba bean-wheat, when grown as sole crops and intercrops. Four traits were used as trait axes for the trait space analysis: canopy height, shoot biomass, tiller/node number, and grain yield. We found that trait spaces differed with crop species and cultivars, and whether they were grown as intercrops or sole crops. Trait spaces differed between high and low fertilization only for the cereals grown in the more productive site (i.e. Denmark). Species grown as intercrops had larger volumes than when grown as sole crops, as a result of trait plasticity. This response to intercropping was apparent in almost all the species grown in Sweden and Denmark, except for wheat in Denmark. The study demonstrated that individual species responded to intercropping compared to sole cropping through the plasticity of traits, which influenced the shape of the hypervolumes to divide up the trait space between the species. The findings are important in illustrating the plastic responses of arable crops, which are relevant for understanding the productivity of species grown in intercrops as compared to sole crops.