Effects of tomato-Sedum alfredii Hance intercropping on crop production and Cd remediation as affected by soil types

Intercropping crops with hyperaccumulators is a proven model for coupling crop safety production and soil heavy metal remediation. And both crop genotypes and soil properties might have great impacts on the effect of intercropping. Therefore, a greenhouse pot experiment was designed to investigate the effects of intercropping different tomato varieties with the cadmium (Cd) hyperaccumulator Sedum alfredii Hance (S. alfredii Hance) on different soils. The results showed that intercropping promoted Cd uptake by S. alfredii Hance and reduced soil total Cd concentration. There was no significant effect of intercropping on tomato yield and Cd concentration. Different tomato varieties had different effects on tomato yield and Cd concentration. The yield of cherry tomato was 1.04 times higher than that of common large fruit tomato, while the Cd concentration in all parts was lower than that of common large fruit tomato. Different typical zonal soils had different effects on tomato production and soil remediation. And among the four studied soils, tomatoes grown on ZJ soil had the highest yields and lowest fruit Cd concentration, making them more suitable for remediation coupled with safety production. This study provided a comprehensive analysis of tomato production benefits and soil remediation effects, which could be useful as a guide in vegetable safety production coupled with soil remediation practices in the Cd-contaminated greenhouse.

Effects of willow and Sedum alfredii Hance planting patterns on phytoremediation efficiency under AC electric field

Heavy metal contamination to soil is tricky due to its difficult removal, long retention time, and biomagnified toxicity. The green and low-cost phytoremediation with electric field treatment and planting pattern selection is an emerging and more effective approach to remove heavy metals from soils. In this study, alternating current (AC) electric field-assisted phytoremediation was examined with different planting patterns, i.e., monoculture willow (Salix sp.), monoculture Sedum alfredii Hance, and interplanting of willow and S. alfredii. AC electric field greatly increased phytoremediation efficiency to soil cadmium (Cd) regardless of planting patterns, either single plant species of willow or S. alfredii. The Cd removal capacity of willow and S. alfredii raises apparently under 0.5 V cm-1 AC electric field. Under different planting patterns of AC electric field treatment, Cd accumulation in the whole plant by interplanting was 5.63 times higher than monoculture willow, but only 0.75 times as high as monoculture S. alfredii. The results showed that AC electric field-assisted interplanting of willow and S. alfredii is a promising remediation technique for efficiently clean-up Cd-contaminated soil.

Experimental dataset of sugarcane-cover crop intercropping trials to control weeds in Reunion Island

Agroecological studies on sugarcane intercropping commonly generate complex datasets. A generic database (AEGIS - Agro-Ecological Global Information System) has been developed to facilitate the use of these datasets. The data described in this paper includes data from 8 experiments carried out on Reunion Island from 2012 to 2021 under three soil and climatic conditions to assess the capacity of cover crops in the sugarcane inter-row to control weed growth. Each experiment consisted of the comparison of three treatments in the inter-row: i) sugarcane with chemical weeding, ii) sugarcane with a cover crop sowed in the inter-row, and iii) sugarcane with spontaneous weed flora in the inter-row. The datasets contain data for sugarcane and cover crop observations (e.g., yield), weed flora, including 104 weed species (e.g., ground cover), crop management (including manual and chemical weedings), soil analyses, and daily weather. This dataset provides an adequate experimental dataset to calibrate or validate crop model simulations under intercropping.

Effects of intercropping on safe agricultural production and phytoremediation of heavy metal-contaminated soils

Intercropping with hyperaccumulators is believed to be an important and efficient way to achieve simultaneous safe agricultural production and phytoremediation of polluted soils. However, some studies have suggested that this technique might facilitate the uptake of heavy metals by crops. To investigate the effects of intercropping on the heavy metal contents of plants and soil, data from 135 global studies were collected and analyzed by meta-analysis. The results showed that intercropping could significantly reduce the contents of heavy metals in the main plants and soils. Plant species was the main factor that affected plant and soil metal contents in the intercropping system, and the heavy metal content could be significantly reduced when members of the Poaceae and Crassulaceae were used as main plants or when legumes were used as intercropped plants. Among all the intercropped plants, the best one for removing heavy metals from the soil was a Crassulaceae hyperaccumulator. These results not only highlight the main factors affecting intercropping systems but also provide reliable reference information for the practice of safe agricultural production coupled with phytoremediation of heavy metal-contaminated farmland.

The effects and interrelationships of intercropping on Cotton Verticillium wilt and soil microbial communities

BACKGROUND

Cotton Verticillium wilt, causing by Verticillium dahliae, has seriously affected the yield and quality of cotton. The incidence of Verticillium wilt in cotton fields has been on the rise for many years, especially after straw has been returned to the fields. Intercropping can reduce the incidence of soil borne diseases and is often used to control crop diseases, but the relationship between the effects of intercropping on microbial communities and the occurrence of plant diseases is unclear. This research explored the relationship between soil microbial community structure and Cotton Verticillium wilt in interplanting of cotton-onion, cotton-garlic, cotton-wheat and cotton monocultures. Amplicon sequencing applied to the profile of bacterial and fungal communities.

RESULTS

The results showed that the disease index of Cotton Verticillium wilt was significantly reduced after intercropping with cotton-garlic and cotton-onion. Chao1 and Sobs indices were not significantly different in the rhizosphere soil and pre-plant soils of the four planting patterns, but the pre-plant fungal shannon index was significantly lower in the cotton-onion intercropping plot than in the other three plots. PCoA analysis showed that the soil microbial communities changed to a certain extent after intercropping, with large differences in the microbial communities under different cropping patterns. The abundance of Chaetomium was highest in the cotton-garlic intercropping before planting; the abundance of Penicillium was significantly higher in the cotton-wheat intercropping than in the other three systems.

CONCLUSION

Cotton-garlic and cotton-onion interplanting can control Cotton Verticillium wilt by affecting the soil microbial community. Fungi of the genera Chaetomium and Penicillium may be associated with plant disease resistance.

Interplanting of rice cultivars with high and low Cd accumulation can achieve the goal of "repairing while producing" in Cd-contaminated soil

Interplanting has been highlighted as a promising, cost-effective, and environmentally friendly solution for the remediation of contaminated soil. In this study, field experiments were conducted to study growth and cadmium (Cd) uptake in monoculture and interplanting systems with rice varieties Changliangyou 772 (C-772) and Changxianggu (Cho-ko-koku). And a pot culture experiment was conducted to investigate the response of the rhizosphere microecology of these two rice varieties. In the interplanting system of the field study, the Cd concentration in the grains of C-772 was significantly reduced (P < 0.05) from 0.30 mg kg^-1 to 0.16 mg kg^-1 and reached the national food safety standard of China (GB2762-2017, 0.20 mg kg^-1), whereas the bioconcentration amount (BCA) per plant of Cd in Cho-ko-koku was significantly increased by 68.18 % (P < 0.05). The land equivalent ratio (LER) and Cd metal removal equivalent ratio (MRER) of the interplanting system were 1.03 and 1.05, illustrating that the interplanting system was superior in terms of yield and Cd elimination. In the pot experiment, the interplanting system significantly (P < 0.05) reduced the iron plaque content on the root surface and organic acids content in the rhizosphere environment of C-772 while markedly increasing those levels in Cho-ko-koku. At ripening stage, the interplanting system significantly decreased the rhizosphere available Cd concentration of C-772 from 0.38 mg kg^-1 to 0.22 mg kg^-1 (P < 0.05), while significantly increased the rhizosphere available Cd concentration of Cho-ko-koku from 0.27 mg kg^-1 to 0.32 mg kg^-1 (P < 0.05). Thus, Cd uptake of C-772 and Cho-ko-koku showed apparent differences. Oxalic and tartaric acid were identified as the most crucial factors affecting Cd uptake by C-772 and Cho-ko-koku in the interplanting system, respectively. In summary, this interplanting system is a promising planting pattern that can simultaneously improve land use efficiency and alleviate Cd pollution.