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publicSep 2024View details →

Data from: Evaluating the effects of cotton intercropping on cool‐season perennial forage persistence, forage mass, and nutritive value in the southeastern United States

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publicJul 2021View details →

Interspecific interactions regulate plant reproductive allometry in cereal-legume intercropping systems

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publicAug 2023View details →

Pan trap and plant-flower visitor observation data for: Multi-species crop mixtures increase insect biodiversity in an intercropping experiment

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publicAug 2022View details →

Temporal stability of productivity is associated with complementarity and competitive intensities in intercropping

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publicJun 2022View details →

Overyielding is accounted for partly by plasticity and dissimilarity of crop root traits in maize/legume intercropping systems

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publicSep 2023View details →

Original data for for intercropped maize experiments, root barrier experiments in intercropped maize, and unilateral shading experiments

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publicDec 2024View details →

Data from: Intercropping generates trait plasticity, which corresponds with year-to-year stability in productivity

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publicJun 2024View details →

Data from: The interplay of intercropping, wildflower strips and weeds in conservation biological control and productivity

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opencc-zeroDec 2015View details →

Data from: Can intercropping with the world's three major beverage plants help improve the water use of rubber trees?

The dramatic expansion of rubber plantations in mainland South-East Asia and south-west China has caused many eco-environmental problems, especially negative hydrological consequences. These problems have gradually worsened and pose formidable threats to rubber agriculture, especially in the light of increasingly frequent extreme weather events. Although rubber-based agroforestry systems are regarded as the best solution for improving the sustainability of rubber agriculture and environmental conservation, plant water use and related interactions have rarely been examined in such systems. We primarily used stable isotope (δD, δ18O and δ13C) methods to test whether intercropping could improve the water use and extreme weather tolerance (extreme cold and drought in our study) of rubber trees in three types of promising agroforestry systems (i.e. rubber with tea, coffee and cocoa) in Xishuangbanna, China. We found that the rubber tree is a drought-avoidance plant with strong plasticity with respect to water uptake. This characteristic is reflected by its ability to cope with serious seasonal drought, allowing it to avoid interspecific competition for water. The rubber trees showed wasteful water behaviour unless they were intercropped with tea or coffee. However, these intercropped species exhibited drought-tolerance strategies and maintained lower water use efficiencies to strengthen their competitive capacity for surface soil water. The stable δ13C values of the intercrop leaves indicated that all the agroforestry systems have stable internal microclimatic environments or higher resistance. Synthesis and applications. This study suggests that interspecific competition for water can enhance the water use efficiency of drought-avoidance plants (i.e. rubber trees) and lead to complementarity between the root distributions of plants in rubber agroforestry systems (i.e. rubber with tea, coffee and cocoa). All agroforestry systems have higher resistance, but tea was the most suitable intercrop in terms of water use because the interspecific competition for water was moderate and the agroforestry system retained much more soil water and improved the water use efficiency of the rubber tree. Considering the root characteristics of the tea trees, we suggest that the crops selected for intercropping with rubber trees should have a relatively fixed water use pattern, short lateral roots and a moderate amount of fine roots that overlap with the roots of the rubber trees in the shallow soil layer.

opencc-zeroDec 2018View details →

Data from: Intercropping of marine finfish in shrimp ponds: a maiden feasibility study

Diversification of shrimp farming with marine finfish in a farmer participatory research model was attempted. The study is intended to find an economically viable finfish culture during the fallow period of shrimp farms. The Silver pompano, Trachinotus blochii intercropped with Pacific white shrimp, Litopenaeus vannamei culture in coastal shrimp ponds was assessed for growth, survival, and economic viability. During the grow-out period of 100 days; fishes grew from 40.23 ± 1.40 g to 256.56 ± 1.08 g in weight and 12.83 ± 0.19 cm to 25.11 ± 0.09 cm in length. The daily weight gain (DWG) and daily length gain (DLG) were 2.16 g/day and 0.12 cm/day, respectively. Relative growth rate (RGR) and specific growth rate (SGR) recorded for weight was 537.80% in 100 days and 1.85% per day, respectively. Pompano has exhibited its sturdiness and adaptability to the land-based culture system as evident by an overall survival percentage of 89.8% including nursery and grow-out phases. The realized feed conversion ratio was 1.94. The culture period of 100 days is found to be enough to attain a desirable harvest size of 250 g. The projected production potential of the experimental demonstration farm of 4500 m2 water spread area for culture was 16.2 tonnes/cycle with a benefit-cost ratio (BCR) of 1.34 over operational cost. The present participatory trial empirically proved the viability of Silver pompano as an intercrop in coastal shrimp ponds. Thus, the introduction of Pompano in shrimp ponds is recommended and can be promoted for sustainable intercropping with shrimp farming along the Indian coast for improving people's livelihoods.

opencc-zeroJun 2021View details →

Nitrogen fixation and crop productivity enhancements codriven by intercrop root exudates and key rhizosphere bacteria

1. Crop diversity management is widely used to increase agricultural productivity and sustainability. Recent studies have demonstrated that maize root exudates can drive interspecific facilitation to enhance N2 fixation of bean in intercropping systems. However, the mechanisms of N2 fixation enhancement stimulated by root exudates in the intercropping systems remain unclear. 2. Four experiments were designed to provide a progressively deeper understanding of how root exudates stimulate microbial-mediated N2 fixation. First, the effects of faba bean/maize intercropping on yields and soil microbial communities were determined in a field experiment. Second, root-derived interspecific facilitation was evaluated using a root partitioning approach. Third, the key microbial taxa in the faba bean rhizosphere were traced using 13C-labeled maize root exudates. Fourth, the codriven mechanism of maize root exudates and microorganisms in the faba bean rhizosphere were explored. 3. Faba bean/maize intercropping with maize residue return increased the yields of faba bean (26%), maize (27%), and broccoli (9.1%) compared to that under monocropping. Nodulin-like 4 (NODL4), chalcone-flavanone isomerase (CFI), and early nodulin-like (ENODL2) gene expression in faba bean roots intercropped with maize increased by 1.5-2.3-fold compared to that observed under monoculture. More than half of the N2 fixation of faba bean increase under intercropping was due to interactions with microorganisms. Nine key bacterial genera in the faba bean rhizosphere were identified by 13C-DNA based stable isotope probing analysis. Among them Agromyces, Arthrobacter, Bacillus, Lysobacter, and Paenibacillus directly fix N2, while Gemmatimonas, Heliobacillus, Natronocella, and Sorangium increase the N2 fixation capacity of Azotobacter by providing additional carbon sources. These key bacteria triggered by maize root exudates played an important role in the rhizosphere facilitation of intercropping. 4. Synthesis and applications. We demonstrated a novel root-root facilitation of N2 fixation and increased crop yields codriven by root exudates and rhizosphere bacteria under faba bean/maize intercropping, and nine key bacteria associated with this process were identified by 13C-DNA based stable isotope probing. We recommend the adoption and optimization of intercropping systems with residue return to reduce the shortcomings of continuous cropping and to increase the sustainability of crop <a>production</a>.

opencc-zeroNov 2023View details →

Long-term effects of intercropping on multi-trophic structure and bio-thermodynamic health of mixed Eucalyptus-native tree plantations

1. The intercropping approach of Eucalyptus and native trees has been widely recommended, as an ideal replacement for monoculture Eucalyptus plantations (EUs), to ameliorate global biodiversity loss and mitigate environmental change. However, both suitable native tree species and the best intercropping ratio between Eucalyptus and native trees have not been determined. 2. To fill this gap, a four-level intercropping gradient of Eucalyptus urophylla planted with eight native tree species was set up (i.e., 20%NS, 30%NS, 40%NS, 50%NS), monitored and compared to a monoculture E. urophylla plantation (EU) and a randomly mixed plantation of nine native tree species (NS) in southern China. 3. The results showed that the intercropping ratio of Eucalyptus and native trees had a long-term effect on tree layer structure and health status and a cascading effect on the thermodynamic health state of soil microbes. Shade-tolerant woody species are more suitable for intercropping with Eucalyptus. Intercropping plantations with not less than 30% native trees were more favorable for long-term survival and growth of both planted Eucalyptus and native trees and provided much more favorable conditions for the natural immigration of other native trees, which leads to a healthy plant community with significantly higher eco-exergy compared to EU. The initial mixing ratio between Eucalyptus and high diversity native trees affected soil fertility through its long-term effects on the biodiversity and bio-thermodynamic state of trees and soil microbes. 4. Synthesis and applications. Our results highlight the long-term positive effect of the intercropping ratio of Eucalyptus and high diversity native trees on multi-trophic biodiversity conservation, bio-thermodynamic health development, and soil fertility conservation. In the conversion of monoculture Eucalyptus plantations (EU) to multi-species plantations, it is recommended to mix more than 30% native tree species that have different ecological niches with Eucalyptus.

opencc-by-4.0Nov 2023View details →

The importance of management on the productivity of cereal-pea intercrops

Poster presented at the Internal Legume Conference, Granada, September 2023

opencc-by-4.0Jan 2022View details →

Dataset of the paper: A first-year melon/cowpea intercropping system improves soil nutrients and changes the soil microbial community

Dataset and raw data

openMar 2022View details →

Raw data for "Assessing Cover Crop and Intercrop Performance Along a Farm Management Gradient" (2022)

This dataset accompanies the publication "Assessing Cover Crop and Intercrop Performance Along a Farm Management Gradient" by Stratton et al. in the journal Agriculture, Ecosystems, and Environment (2022). <a href="https://doi.org/10.1016/j.agee.2022.107925">https://doi.org/10.1016/j.agee.2022.107925</a> METHODS: We conducted our experiment between May 2018 and December 2019 on 14 farms in the eastern coastal highlands region of Santa Catarina, Brazil. The mean altitude of sites was 467 m (+/- 161 m).  Eastern Santa Catarina has a subtropical climatic pattern, with mean annual rainfall ranging from 1,500-1,700 mm (Wrege et al., 2012). While 2018 had typical weather patterns for the region, 2019 was a dry year, particularly during the spring months (Appendix B, Table B.1). All farms were located in the Colonial Serrana Catarinense soil microregion, one of 16 designated microregions in the state of Santa Catarina (EMBRAPA, 2004). Primary soil types in our study site are associations of dystric Cambisols and haplic Acrisols (typic Dystrocryepts and typic Paleudults in the USDA Soil Taxonomy), which tend to be moderately to highly acidic, with limited soil nutrient availability and moisture retention (EMBRAPA, 2004; IUSS Working Group WRB, 2015; USDA, 2010). To support crop production, farmers in the region typically apply lime (calcium and magnesium carbonate) to agricultural fields to increase soil pH from <5.5 to 6 (Comissão de Química e Fertilidade do Solo - RS/SC, 2016). Exact farm locations within the region are not given and farmer identities have been anonymized. Experimental design The fully factorial experiment had six treatments (Figure 2): (1) cover crop + pea-cucumber intercrop, (2) cover crop + pea monocrop, (3) cover crop + cucumber monocrop, (4) fallow + pea-cucumber intercrop, (5) fallow + pea monocrop, and (6) fallow + cucumber monocrop. Due to the timing of farm recruitment, only conventional and transitioning farms participated in the first year of cover cropping (2018); agroecological farms were added to the study during the vegetable intercropping period of 2018 and had their first round of cover cropping in 2019. The cover crop mixture treatment was designed to emulate traditional practices in the region, as well as to include functionally complementary legume and grass species: common vetch (Vicia sativa L.) and black oat (Avena strigosa Schreb). We also selected vegetables with distinct ecological functional traits, such that intercropping represented an increase in functional diversity relative to mono-cropped vegetables. Snow peas are N-fixing legumes with a vining, upright structure and a deep root system, whereas cucumbers are low-lying, non-legume cucurbits that provide groundcover and have a relatively shallow, extensive root system.   Cover crop treatments consisted of two adjacent 50 m2 plots in each field, one of which was planted with the cover crop mixture; the other served as a weedy fallow control. In 2018, the cover crop mixture seeding rate was 72 kg/ha black oat and 36 kg/ha common vetch. Due to poor vetch performance in mixtures at this rate, we increased the vetch seeding rate to 60 kg/ha in 2019, maintaining the black oat rate from 2018. Cover crop seeds were inoculated with the Brazilian strain Rhizobium etli (SEMIA 384; source: FEPAGRO) at 4 g/kg vetch seed prior to planting. Cover crops were grown until peak flowering, and then cover crops (and weeds in the fallow) were incorporated into the soil by rototiller (n = 7 farms) or by hand hoeing (n = 7 farms), based on farms’ available machinery, between September 5-10 in 2018 and September 10-18 in 2019 (approximately one week following cover crop sampling on each farm).   Vegetables were planted two weeks following cover crop and weed biomass incorporation within a period of 7-10 days across sites. Harvest dates were spaced such that crops were growing for approximately the same period across farms. The 50 m2 plots were each divided into three intercrop treatments with a ~1 m2 pathway between each treatment, for a total of 6 treatments randomly assigned to plots per 100 m2. We planted a climbing variety of snow peas (Pisum sativum subsp. sativum var. macrocarpum, “Torta de flor roxa”) and pickling cucumber (Cucumis sativa L. var. Pepino HT 05) in intercrops and in their respective monocrops, using a replacement design (i.e., equivalent crop densities in all treatments). Snow pea seeds were inoculated with Rhizobium leguminosarum var. viceae (SEMIA 3007/BR 619, source: UFSC ENR/CCA) at a rate of 4 g/kg directly prior to planting. There were five rows of crops per treatment, with only the three middle rows harvested to limit edge effects. In-row spacing was 60 cm for cucumber and 20 cm for peas, with 60 cm between rows in both intercrops and monocrops. Cucumbers were grown as starts for 2.5 weeks before planting, and peas were planted from seed on the same planting date as cucumber starts.   In the summer between January and May 2019 all fields were planted to a sunflower (Helianthus annuus L.) crop, which was incorporated into the soil during flowering approximately two weeks prior to cover crop planting in 2019. Because we sought to understand the effects of crop diversification given existing water and nutrient limitations on working farms, the experiment was entirely rainfed and legume N fixation was the sole external N source. Soil sampling and analysis Prior to the first cover cropping period, we collected a composite sample of 15-20 soil cores (2.5 cm diameter, 20 cm depth) on both the cover crop and fallow sides of each experimental field (n = 28) for analysis of baseline conditions (see Appendix B for full details). Briefly, soil was analyzed for pH, macro- and micronutrients, and soil organic matter (SOM) by the Santa Catarina State Agricultural Agency (EPAGRI) in Ituporanga, Santa Catarina, Brazil, using standard protocols (Comissão de Química e Fertilidade do Solo - RS/SC, 2016). pH was measured with a glass electrode both with and without Sikora’s buffer, and buffered pH is used throughout this paper (Tecnal TEC-11 MP). Soil organic C and total soil N to 20 cm were determined by dry combustion on a Leco TruMac CN Analyzer (Leco Corporation, St. Joseph, Michigan, USA). We measured soil texture (% clay, sand, and silt) using a total dispersion method with sodium hexametaphosphate (Empresa Brasileira de Pesquisa Agropecuaria (EMBRAPA), 1997). Bulk density was estimated from the mass of 10 fresh soil cores per treatment, with subsequent accounting for soil moisture.   We measured C mineralization as a baseline indicator of soil microbial activity and biological soil fertility at the start of the experiment, and N mineralization as a response variable following the second year of cover crop treatments. Specifically, using the baseline soil sample, we conducted a short-term (24-hour) C mineralization assay to determine potentially mineralizable C (PMC), which measures the flux of CO2 following re-wetting of previously air-dried, sieved soil using a Li-Cor (Franzluebbers et al., 2000; Hurisso et al., 2016). To measure potentially mineralizable N (PMN), we conducted a two-week aerobic incubation using fresh soil collected at vegetable crop planting in the second year of the experiment (spring 2019), two weeks after cover crop and weed biomass incorporation (Drinkwater et al., 1996; Appendix B.2). PMN was calculated as the difference between extractable soil inorganic N (NH4+ and NO3-) at the start and end of the incubation. We used pre-incubation extractable inorganic N concentration (mg/kg) as a measure of soil inorganic N availability at vegetable crop planting.  Cover crop sampling and analysis Cover crop biomass sampling took place from August 28-September 2 in 2018 and September 4-10 in 2019. During peak flowering of both common vetch and black oat, we destructively harvested the aboveground biomass of cover crop mixtures and weedy fallows from two 0.5 x 0.5 m quadrats of each treatment per field. We took care to avoid treatment edges, cut plant material to the soil surface, and separated harvested plant material by species, grouping all weeds together. Aboveground biomass was dried in a forced-air oven at 60 °C for 48 hours. Following grinding in a Wiley mill to 2 mm, % N and C content was determined by dry combustion on an elemental analyzer (Leco, as above). Community-weighted means were calculated for total aboveground biomass C and N in cover crop species and weeds, to determine the overall C and N inputs to soil following incorporation of biomass on each farm. We measured biological N2 fixation in inoculated common vetch from the cover crop phase of the experiment in 2018 and 2019. Vetch N fixation was estimated using the 15N natural abundance method (Shearer and Kohl, 1986), which compares stable N isotope ratios in the legume and reference species (oat monocultures) (Appendix C).  Vegetable crop sampling and analysis To capture the full production period of both cucumber and pea crops, yield was measured in two harvests, which were approximately 14 days apart on each farm. Harvest dates ran from November 16-December 6 in 2018 and November 20-December 4 in 2019. We measured yield by weighing all harvestable fruit from three designated, representative row sections (6 plants on average per row) per crop type per treatment. Rows were sampled from the center of each treatment to reduce edge effects. We calculated yield as total crop production (g) per plant harvested in each row. Mean yield for each crop type was calculated as the average of the three harvested rows per treatment on a per-plant basis and was then aggregated to the plot and hectare level based on experimental planting densities. Total N harvested, or “N yield”, was calculated for all treatments by multiplying the % N in each vegetable crop by its yield (kg/ha) after accounting for crop water content. Using plot-level yield data, we subsequently calculated the relative yield total (Land Equivalent Ratio, LER) for intercrop treatments by farm using the standard equation (Vandermeer, 1989) (Table 1). As a relative measure of total crop production per area, when mean LER > 1, intercrops were considered to have “overyielded” compared to their component monocrops. We calculated the LER for N yield (LERN in kg N/ha) using the same formula.   At the second vegetable harvest, we destructively sampled whole aboveground crop biomass, including residues and remaining fruits, from the designated experimental rows.  Following the harvest, a minimum of six representative cucumbers per treatment (from different plants) per farm were washed in deionized water, air-dried, sliced, and the middle sections were combined into a homogenized, composite sample of ~100 g and then dried for one week at 60 ºC. All peas from each treatment’s subplot were washed in deionized water, air-dried, de-stemmed, chopped, and each homogenized sample (35-60 g fresh material) was subsequently dried at 60 ºC in a forced-air oven for 48 h to one week, until fully desiccated. Dried vegetable biomass residues were ground using a Wiley mill; vegetable crop samples were ground in a coffee grinder; and all vegetable samples were analyzed for % C and N on a LECO elemental analyzer. See supplemental material from Stratton et al. 2022 for further detailed information on methods.

opencc-zeroMay 2022View details →

Soil biota is decisive for overyielding in intercropping under low phosphorus conditions

Cereal/legume intercropping typically increase crop yield, however, the mechanisms through which soil microbes mediate overyielding in intercropping under different nutrient availability remain elusive. Here we examined the effect of soil biota and phosphate (P) availability on intercropping advantages in wheat (Triticum aestivum) /faba bean (Vicia faba) systems using a pot experiment consisting of soil sterilization treatment and different P supply levels. A complementary experiment on the contribution of different microbial groups was also included using the removal method. Intercropping advantage was observed only in the presence of microbes and was mainly associated with increase of wheat biomass. Overyielding effect was stronger under low-P than high-P conditions, and was negatively correlated with P availability and the effect of soil biota in the monoculture. The effect was likely related to the enlarged active P pools and modified microbial communities associated with the alteration of rhizosphere traits (protons and carboxylates) by the neighboring faba bean. Similarly, simplification of soil microbes significantly increased the growth and P uptake of wheat plants while faba bean growth was less affected. Synthesis and applications. Our research provides compelling evidence that soil microbiome is important in driving intercropping overyielding by regulating interspecific interactions under nutrient limited conditions. These findings have important implications for crop species choice in designing and managing intercropping systems where crop functional traits, soil microbiome and nutrient management should be integrated in pursuit of sustainable agriculture.

opencc-zeroOct 2021View details →

Third and fourth trophic level composition shift in an aphid-parasitoid-hyperparasitoid food web limits aphid control in an intercropping system

1. Understanding how resource diversification affects ecological interactions, food web structure and ecosystem functioning is essential in both fundamental and applied ecology. While plant diversification strategies (either in- or around-field) are often proposed in agricultural landscapes as practices to improve the biological control of herbivores by natural enemies, results remain variable and unsure. 2. Here, we studied the effect of an in-field diversification practice (the intercropping of leguminous crops within cereal fields, an increasingly common practice but with inconsistent results on biological control) on cereal aphid control and the structure of a cereal-aphid-parasitoid-hyperparasitoid food web for two years. 3. We report that aphid control was not increased in mixed fields, nor was cereal parasitoid diversity and food web complexity. Nevertheless, the provision of alternative hosts in mixed fields led to a functional community composition shift, favouring generalist parasitoid species over specialist ones. 4. Moreover, we observed a higher hyperparasitism rate in mixed fields, suggesting that secondary parasitoids were favoured by alternative resources, which may have disrupted aphid control by primary parasitoids. 5. Synthesis and applications. This study demonstrates that parasitoid community composition shift and increased top-down control by the fourth trophic level can impact parasitoid efficiency to control herbivores. These results highlight the necessity to study fine-scale mechanisms within food webs to be able to set-up efficient methods to support biodiversity and associated ecosystem services in agricultural landscapes.

opencc-by-4.0Jul 2023View details →

Datasets for crop, soil properties and soil greenhouse gas emissions from an intercropping experiment with broccoli and fava bean

Datasets with all properties measured during three crop cycles of an experiment developed to assess the efficiency of intercropping between broccoli and fava bean to enhance crop productivity, soil health and carbon sequestration and storage and reduce soil greenhouse gas emissions and the use of external inputs.  We compared a broccoli monocrop (Brassica oleracea var. italica Plenck), a fava bean monocrop (Vicia faba L.) and different broccoli-fava bean intercropping systems in three winter crop cycles: 2018/2019, 2019/2020 and 2020/2021. The intercropping systems were: i) mixed intercropping (alternation within the same row of broccoli and fava bean plants), row intercropping 1:1 (combination of alternate rows of broccoli - fava bean) and row intercropping 2:1 (combination of two rows of the broccoli crop and one row of fava bean).

publicMay 2022View details →

Soil biota is decisive for overyielding in intercropping under low phosphorus conditions

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