Disentangling the contribution of trait plasticity to improve the productivity of a maize–soybean intercrop system for the Midwest, USA

AimPhenotypic plasticity is hypothesized to contribute to a species’ capacity to occupy broader ranges of conditions and to optimally exploit resource‐rich environments. Although this is supported by case studies of individual species, we do not know whether larger plasticity in functional traits is generally associated with ecological characteristics of species such as their niche breadth or niche position. Here, we test whether there is such a relationship for plasticity in leaf functional traits.LocationCentral Europe.MethodsWe surveyed 110–132 grassland plant species for plasticity in five leaf traits [leaf thickness, leaf greenness, specific leaf area, leaf dry matter content (LDMC) and plant height] and for biomass changes in response to experimental fertilization, shading and waterlogging. Trait plasticity and changes in biomass were compared with species niche characteristics along three environmental axes (light, nutrient and soil moisture) derived from a vegetation‐plot database.ResultsAlthough response of several traits to experimental treatments correlated with niche position and breadth (change in leaf thickness, greenness and biomass in response to fertilization; change in LDMC due to shading; and change in plant height and biomass due to waterlogging), we did not find evidence that species with broader niches or species from resource‐rich environments are more plastic. Ecological generalists even turned out to be less plastic in some traits, including leaf thickness after fertilization and waterlogging. Generalists also displayed smaller plastic response averaged across all five traits (‘composite plasticity’), though the relationship was not statistically significant. This composite plasticity was positively related to absolute change in biomass in all experimental treatments.Main conclusionsOur results suggest that larger species‐level plasticity in leaf traits is not necessarily associated with a capacity to occupy a broader range of environments or with growth in resource‐rich habitats; rather, it may indicate species’ sensitivity to environmental changes.

Functional-structural plant (FSP) models are useful tools for understanding plant functioning and how plants react to their environment. Developing tree FSP models is data-intensive and measuring tree architecture using conventional measurement tools is a laborious process. Light detection and ranging (LiDAR) could be an alternative nondestructive method to obtain structural information about tree architecture. This research investigated how terrestrial LiDAR (TLS)-derived tree traits could be used in the design and parameterization of tree FSP models. A systematic literature search was performed to create an overview of tree parameters needed for FSP model development. The resulting structural parameters were compared to LiDAR literature to get an overview of the possibilities and limitations. Furthermore, a tropical tree and Scots pine FSP model were selected and parametrized with TLS-derived parameters. Quantitative structural models were used to derive the parameters and a total of 37 TLS-scanned tropical trees and 10 Scots pines were included in the analysis. Ninety papers on FSP tree models were screened and eight papers fulfilled all the selection criteria. From these papers, 50 structural parameters used for FSP model development were identified, from which 28 parameters were found to be derivable from LiDAR. The TLS-derived parameters were compared to measurements, and the accuracy was variable. It was found that branch angle could be used as model input, but internode length was unsuitable. Outputs of the FSP models with TLS-derived branch angle differed from the FSP model outcomes with default branch angle. Results showed that it is possible to use TLS for FSP model inputs, although with caution as this has implications for the model variable outputs. In the future, LiDAR could help improve efficiency in building new FSP models, increase the accuracy of existing models, add metrics for optimization, and open new possibilities to explore previously unobtainable plant traits.

The intercropping system with the right dose of phosphorus will show higher yields than the monoculture planting system. The study was carried out with the aim of: (i) comparing crop yields between intercropping and monoculture planting systems, (ii) comparing the efficiency of land use of each planting system, and (iii) phosphorus doses which provide the highest yield for each cropping system. The study was conducted at the Experimental Garden of the Faculty of Agriculture, University of Sultan Ageng Tirtayasa Cikuya Karang Kitri District Serang, starting from April to July 2019. The experiment used a factorial randomized block design. The first factor is the planting system consisting of three levels, namely the system of soybean monoculture planting, maize monoculture planting system, and intercropping system of soybean+corn. The second factor is the dose of phosphorus fertilizer consisting of two levels, namely 25 kg.ha−1 and 100 kg.ha−1. Each treatment combination was repeated three times. To find out the purpose of the study used the Land Equity Ratio (LER) indicator and Variant Analysis of observational data which included: plant height, number of leaves, weight per plant, crop weight per plot and seed dry weight. The plant growth with corn monoculture is better than intercropping system. The yield of plants with intercropping systems is higher than that of monoculture systems. Plant yields in both cropping systems (intercropping and monoculture) were higher by giving phosphorus doses of 100 kg.ha−1 compared to 25 kg.ha−1.

Coastal wetland ecosystems are increasingly threatened by escalating salinity levels, subjecting plants to salinity stress coupled with interactions in the community. Abiotic factors can disrupt the balance between competition and facilitation among plant species. Investigating the effects of different neighboring species and trait plasticity could extend the stress gradient hypothesis and enhance understanding of vegetation distribution and diversity in salt marshes. We conducted a greenhouse experiment and investigated the plastic response of wetland grass Phragmites australis to seven neighboring plants of three functional types (conspecifics, graminoids and forbs) under soil salinity (0 and 10 g/L). Plant height, base diameter, density, leaf thickness, specific leaf area and total and part biomasses were measured. Additionally, the relative interaction index (based on biomass) and the relative distance plasticity index (RDPI) were calculated. Salinity significantly reduced the biomass, height, density and diameter of P. australis. The functional types of neighboring plants also significantly affected these growth parameters. The influence of graminoids on P. australis was negative under 0 g/L, but this negative effect shifted to positive facilitation under 10 g/L. The facilitation effect of forbs was amplified under salinity, both supporting the stress gradient hypothesis. The growth traits of P. australis had a plastic response to salinity and competition, such as increasing belowground biomass to obtain more water and resources. The RDPI was higher under salt conditions than in competitive conditions. The plant–plant interaction response to stress varies with plant functional types and trait plasticity.

Computational botany: advancing plant science through functional–structural plant modelling

Phenotypic plasticity is an important adaptive strategy that enables plants to respond to environmental changes, particularly temperature fluctuations associated with global warming. In this study, the phenotypic plasticity of Iris pumila leaf traits in response to an elevated temperature (by 1 °C) was investigated under controlled experimental conditions. In particular, we investigated important functional and mechanistic leaf traits: specific leaf area (SLA), leaf dry matter content (LDMC), specific leaf water content (SLWC), stomatal density (SD), leaf thickness (LT), and chlorophyll content. The results revealed that an elevated temperature induced trait-specific plastic responses, with mechanistic traits exhibiting greater plasticity than functional traits, reflecting their role in short-term acclimation. SLA and SD increased at higher temperatures, promoting photosynthesis and gas exchange, while reductions in SLWC, LDMC, LT, and chlorophyll content suggest a trade-off in favor of growth and metabolic activity over structural investment. Notably, chlorophyll content exhibited the highest plasticity, emphasizing its crucial role in modulating photosynthetic efficiency under thermal stress. Correlation analyses revealed strong phenotypic integration between leaf traits, with distinct trait relationships emerging under different temperature conditions. These findings suggest that I. pumila employs both rapid physiological adjustments and longer-term structural strategies to cope with thermal stress, with mechanistic traits facilitating rapid adjustments and functional traits maintaining ecological stability.

Crop canopies are composed of individual plants. Yet, in the analysis of crop characteristics such as canopy photosynthesis, growth and performance, plants are normally not considered as individual entities with their own developmental pattern and plastic responses to their environment. Therefore, in research questions that implicitly or explicitly contain aspects of individual plant development, modelling tools that scale up processes at the level of the plant to the level of the canopy can be used. In this chapter, the functional-structural plant (FSP) modelling approach will be introduced. FSP modelling provides the possibilities to simulate individual plants in a stand setting, and their architecture in 3D over time. It can take into account light interception and scattering at the level of the leaf as a function of leaf size, angle and optical properties, and use this information to determine photosynthesis, photomorphogenesis, and overall plant growth and development. Therefore, FSP modelling can be used to translate individual plant behaviour to whole canopy performance while taking into account phenotypic variation between individuals and plastic responses to local conditions, as well as the consequences of active manipulation of plant architecture such as pruning or herbivory.

Plant species mixtures improve productivity over monocultures by exploiting species complementarities for resource capture in time and space. Complementarity results in part from competition avoidance responses that maximize resource capture and growth of individual plants. Individual organs accommodate to local resource levels, e.g. with regard to nitrogen content and photosynthetic capacity or by size (e.g. shade avoidance). As a result, the resource acquisition in time and space is improved and performance of the community as a whole is increased. Modelling is needed to unravel the primary drivers and subsequent dynamics of complementary growth responses in mixtures. Here, we advocate using functional-structural plant (FSP) modelling to analyse the functioning of plant mixtures. In FSP modelling, crop performance is a result of the behaviour of the individual plants interacting through competitive and complementary resource acquisition. FSP models can integrate the interactions between structural and physiological plant responses to the local resource availability and strength of competition, which drive resource capture and growth of individuals in species mixtures. FSP models have the potential to accelerate mixed-species plant research, and thus support the development of knowledge that is needed to promote the use of mixtures towards sustainably increasing crop yields at acceptable input levels.

AimThe usual hypothesis about the relationship between niche breadth and range size posits that species with the capacity to use a wider range of resources or to tolerate a greater range of environmental conditions should be more widespread. In plants, broader niches are often hypothesized to be due to pronounced phenotypic plasticity, and more plastic species are therefore predicted to be more common. We examined the relationship between the magnitude of phenotypic plasticity in five functional traits, mainly related to leaves, and several measures of abundance in 105 Central European grassland species. We further tested whether mean values of traits, rather than their plasticity, better explain the commonness of species, possibly because they are pre‐adapted to exploiting the most common resources.LocationCentral Europe.MethodsIn a multispecies experiment with 105 species we measured leaf thickness, leaf greenness, specific leaf area, leaf dry matter content and plant height, and the plasticity of these traits in response to fertilization, waterlogging and shading. For the same species we also obtained five measures of commonness, ranging from plot‐level abundance to range size in Europe. We then examined whether these measures of commonness were associated with the magnitude of phenotypic plasticity, expressed as composite plasticity of all traits across the experimental treatments. We further estimated the relative importance of trait plasticity and trait means for abundance and geographical range size.ResultsMore abundant species were less plastic. This negative relationship was fairly consistent across several spatial scales of commonness, but it was weak. Indeed, compared with trait means, plasticity was relatively unimportant for explaining differences in species commonness.Main conclusionsOur results do not indicate that larger phenotypic plasticity of leaf morphological traits enhances species abundance. Furthermore, possession of a particular trait value, rather than of trait plasticity, is a more important determinant of species commonness.

Colonization of a novel environment is expected to result in adaptive divergence from the ancestral population when selection favors a new phenotypic optimum. Local adaptation in the new environment occurs through the accumulation and integration of character states that positively affect fitness. The role played by plastic traits in adaptation to a novel environment has generally been ignored, except for variable environments. We propose that if conditions in a relatively stable but novel environment induce phenotypically plastic responses in many traits, and if genetic variation exists in the form of those responses, then selection may initially favor the accumulation and integration of functionally useful plastic responses. Early divergence between ancestral and colonist forms will then occur with respect to their plastic responses across the gradient bounded by ancestral and novel environmental conditions. To test this, we compared the magnitude, integration, and pattern of plastic character responses in external body form induced by shallow versus open water conditions between two sunfish ecomorphs that coexist in four postglacial lakes. The novel sunfish ecomorph is present in the deeper open water habitat, whereas the ancestral ecomorph inhabits the shallow waters along the lake margin. Plastic responses by open water ecomorphs were more correlated than those of their local shallow water ecomorph in two of the populations, whereas equal levels of correlated plastic character responses occurred between ecomorphs in the other two populations. Small but persistent differences occurred between ecomorph pairs in the pattern of their character responses, suggesting a recent divergence. Open water ecomorphs shared some similarities in the covariance among plastic responses to rearing environment. Replication in the form of correlated plastic responses among populations of open water ecomorphs suggests that plastic character states may evolve under selection. Variation between ecomorphs and among lake populations in the covariance of plastic responses suggests the presence of genetic variation in plastic character responses. In three populations, open water ecomorphs also exhibited larger plastic responses to the environmental gradient than the local shallow water ecomorph. This could account for the greater integration of plastic responses in open water ecomorphs in two of the populations. This suggests that the plastic responses of local sunfish ecomorphs can diverge through changes in the magnitude and coordination of plastic responses. Although these results require further investigation, they suggest that early adaptive evolution in a novel environment can include changes to plastic character states. The genetic assimilation of coordinated plastic responses could result in the further, and possibly rapid, divergence of such populations and could also account for the evolution of genes of major effect that contribute to suites of phenotypic differences between divergent populations.

Colonization of a novel environment is expected to result in adaptive divergence from the ancestral population when selection favors a new phenotypic optimum. Local adaptation in the new environment occurs through the accumulation and integration of character states that positively affect fitness. The role played by plastic traits in adaptation to a novel environment has generally been ignored, except for variable environments. We propose that if conditions in a relatively stable but novel environment induce phenotypically plastic responses in many traits, and if genetic variation exists in the form of those responses, then selection may initially favor the accumulation and integration of functionally useful plastic responses. Early divergence between ancestral and colonist forms will then occur with respect to their plastic responses across the gradient bounded by ancestral and novel environmental conditions. To test this, we compared the magnitude, integration, and pattern of plastic character responses in external body form induced by shallow versus open water conditions between two sunfish ecomorphs that coexist in four postglacial lakes. The novel sunfish ecomorph is present in the deeper open water habitat, whereas the ancestral ecomorph inhabits the shallow waters along the lake margin. Plastic responses by open water ecomorphs were more correlated than those of their local shallow water ecomorph in two of the populations, whereas equal levels of correlated plastic character responses occurred between ecomorphs in the other two populations. Small but persistent differences occurred between ecomorph pairs in the pattern of their character responses, suggesting a recent divergence. Open water ecomorphs shared some similarities in the covariance among plastic responses to rearing environment. Replication in the form of correlated plastic responses among populations of open water ecomorphs suggests that plastic character states may evolve under selection. Variation between ecomorphs and among lake populations in the covariance of plastic responses suggests the presence of genetic variation in plastic character responses. In three populations, open water ecomorphs also exhibited larger plastic responses to the environmental gradient than the local shallow water ecomorph. This could account for the greater integration of plastic responses in open water ecomorphs in two of the populations. This suggests that the plastic responses of local sunfish ecomorphs can diverge through changes in the magnitude and coordination of plastic responses. Although these results require further investigation, they suggest that early adaptive evolution in a novel environment can include changes to plastic character states. The genetic assimilation of coordinated plastic responses could result in the further, and possibly rapid, divergence of such populations and could also account for the evolution of genes of major effect that contribute to suites of phenotypic differences between divergent populations.

Background: Intercropping increases crop yield per unit area by intensifying the use of land. Cultivation of maize with leafy vegetables provides better use of land and other environmental resources, which results in higher economic yield. The current investigation aimed to study the effect of maize-spinach and maize-radish intercropping on growth and yield of maize under rainfed condition of Namsai district of Arunachal Pradesh. Methods: The field experiment was conducted during 2021 in randomized block design consisting of 3 treatments i.e. T1- Sole Maize, T2- Maize + spinach and T3- Maize + radish with four replications. Observations on growth and yield parameters and yield of maize were recorded on harvesting of the crop. The results were analysed using standard statistical procedures of ANOVA. Result: In maize + spinach and maize + radish intercropping, plant height (176.3 cm), numbers of leaves (15.49) and leaf area (5407 cm2 plant-1) were significantly greater in sole maize than the intercropping system. On the other hand, the yield parameters as well as yield of maize was higher in maize + radish intercropping as compared to maize + spinach and sole maize system. The grain yield of maize under maize + radish intercropping was 3066.25 kg ha-1. The B:C (1.92) was significantly higher in intercrops than the sole maize crop. From this study, it can be concluded that the intercrops are agronomically and economically viable than sole cropping. The intercropping of maize with radish would be profitable due to higher yield of maize as well as B:C (2 rows of maize and 2 rows of soybean) under farmer’s field condition of Namsai district of Arunachal Pradesh.

Intercropping system is a common method and it can increase the productivity, use efficiency of irrigation water and land and improve soil fertility.Therefore, the current investigation was conducted during 2016/2017, 2017/2018 and 2019/2020 seasons to study the effect of intercropping faba bean (main crop) -onion (secondary crop) on the yield and yield components and nutrient uptake.The experiment design was a randomized complete blocks, with three replicates.The experiment included 11 treatments of cropping system (sole faba bean, sole onion, 1faba bean:1 onion, 1faba bean:2onion, 1faba bean:3onion, 2faba bean:1onion, 2faba bean:2onion, 2faba bean:3onion, 3faba bean:1onion, 3faba bean:2onion and 3faba bean:3onion).Results showed that 1faba bean :3onion was not significantly different as compred, with sole onion and recorded the highest value of vegetative parameters; plant height (cm), leaf number, bulb diameter (cm) and plant fresh weight (g).Same trend was observed for yield and yield components, and nutrient uptake compared to other intercropping systems.However, regarding to faba bean vegetative characters, 3faba bean :1onion gave the greatest value with no significant difference comparing with sole faba bean and other intercropping systems treatments.Similar trend was observed for nitrogen, phosphorus and potassium uptake.Among all intercropping and sole faba bean treatments, 3faba bean:1onion recorded significant increase in total yield of faba bean with an increase percentage 13.51%,16.55% and 13.84% during 1 st , 2 nd , and 3 rd seasons, respectively.Moreover, the highest land equivalent ratio was obtained with 3faba bean:1onion in the three seasons, which were 1.249, 1.248 and 1.275, respectively.This was followed by 1faba bean: 3onion, which were 0.999, 0.923 and 1.005 in the 2016/2017, 2017/2018 and 2019/2020 seasons, respectively.Taken together, the intercropping system of 3faba bean:1onion or 1faba bean: 3onion could be againful model to obtain the greatest use efficiency of land and irrigation water.

Intercropping has great potential for alleviating arable land competition, improving land output and promoting sustainable agricultural development. However, the applicability of maize-soybean strip intercropping under drip fertigation in arid northwest China remains unclear, especially under various row configurations. A two-season (2022 and 2023) field experiment was performed in the Hexi Region of northwest China to investigate the responses of plant growth, yield performance, water-land productivity and economic profit of drip-fertigated maize-soybean strip intercropping systems to eight row configurations. The results showed that intercropping significantly reduced aboveground biomass accumulation of maize and soybean by 18.77% and 47.81% on average compared to monocropping, respectively. Intercropping significantly decreased the 100-grain weight, ear length and ear width of maize, and reduced the 100-grain weight and pod number of soybean, resulting in reduced grain yields of intercropped maize and soybean (by 13.08% and 48.73%, respectively), but two rows of maize alternating with four rows of soybean (M2S4), three rows of maize alternating with four rows of soybean (M3S4), four rows of maize in wide and narrow rows alternating with four rows of soybean (M4S4-MN), and four rows of maize in wide and narrow rows alternating with six rows of soybean (M4S6-MN) produced greater population grain yield compared to monocropping. Among all intercropping systems, the largest water-land productivity and economic profit occurred in M2S4 (1.61 in 2022 and 1.42 in 2023 for land equivalent ratio; 29.23 kg ha−1 mm−1 in 2022 and 28.22 kg ha−1 mm−1 in 2023 for water productivity; 23,965 CNY ha−1 in 2022 and 23,059 CNY ha−1 in 2023 for economic profit), followed by M4S4-MN (1.53 in 2022 and 1.36 in 2023 for land equivalent ratio; 27.11 kg ha−1 mm−1 in 2022 and 26.58 kg ha−1 mm−1 in 2023 for water productivity; 22,327 CNY ha−1 in 2022 and 22,224 CNY ha−1 in 2023 for economic profit). The M2S4 is thus the optimal row configuration for drip-fertigated maize-soybean strip intercropping systems in terms of grain yield, economic profit and land productivity, while the M4S4-MN is recommended by further considering the efficiency of mechanized sowing and harvesting.

Above‐ground biomass (AGB) is an important indicator of grassland ecosystem performance. Easily measured plant functional traits (PFTs) may provide useful predictors of the response of plants to grazing. Understanding the response of PFTs to grazing and the relationship between PFTs and AGB is very important for effectively predicting the response of ecosystems to grazing and rangeland management. A grazing experiment was conducted in Gangcha County, Qinghai Province, in the northeastern part of the Qinghai–Tibet Plateau in 2012 and 2013. We investigated the response of PFTs in three dominant species ( Elymus nutans , Kobresia humilis , and Stipa purpurea ) to grazing, using six stocking rates. Plant height (PH), plant weight, leaf area, and leaf dry biomass of these three dominant species had significantly negative relationships with stocking rate. Leaf thickness (LT) of these three species usually showed a unimodal response to grazing. Specific leaf area generally showed a quadratic relationship with grazing intensity. No consistent effects of grazing were observed on nitrogen content per unit mass ( N mass ) and nitrogen content per unit area ( N area ). PH, leaf area, and leaf dry mass (LDM) were positively associated with AGB, but LT, N mass , and N area had no statistically significant association with AGB. We thus conclude that PH, leaf area, and LDM best predict the effects of grazing on AGB. Finally, 2.87 sheep/ha is recommended as the optimal stocking rate in this region to maintain the health of this grassland ecosystem and to allow for sustainable development.