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Neocosmospora solani causes Fusarium wilt disease and root rot, which are serious problems worldwide. To determine the growth inhibition of Neocosmospora solani by Trichoderma hamatum volatile organic compounds (VOCs), the major chemical components of Trichoderma hamatum VOCs and the differences in their contents at different times were analysed, and the activity of these components was evaluated. The antifungal activity of Trichoderma hamatum was measured by a screening test, as Trichoderma hamatum exhibited strong antagonism against Neocosmospora solani in vitro. The double plate technique was used to verify the activity of Trichoderma hamatum VOCs, and the inhibition rate was 63.77%. Neocosmospora solani mycelia were uneven and expanded, the contents of the cells leaked, and the mycelia shrank and presented a diaphragm in the hyphae upon Trichoderma hamatum VOCs treatment. Trichoderma hamatum VOCs and their contents at different times were analysed by using gas chromatography–mass spectrometry. 6-Pentyl-2H-pyran-2-one clearly presented in greater amounts than the other components on day 3, 4, 5, and 6. VOCs from Trichoderma hamatum exhibited evident effects on the percentage of healthy fruit after day 3. Moreover, Trichoderma hamatum can improve the biological control of diseases caused by soilborne pathogens, and can be applied in biocontrol fields. [ABSTRACT FROM AUTHOR]

Manganese toxicity is a major obstacle to agriculture in acid soils. Dark pericarp disease (DPD) is a newly spread physiological disorder induced by excess Mn in litchi, leading to undesirable fruit appearance and substantial economic loss. In this work, broadcast of alkaline soil conditioner in winter, followed by foliar sprays of ascorbic acid and sulfur solution at fruit development, was adopted to examine the effect of these combinations on DPD alleviation in a litchi orchard, with DPD morbidities of 70~85% in recent ten years. The combination of soil conditioner broadcast and foliar water spray was used as the control. At harvest, DPD incidence was significantly decreased by sulfur spray (3.3 ± 1.0%) and slightly reduced by ascorbic acid spray (10.7 ± 8.0%) compared to the control (12.9 ± 7.6%). Soil pH and available Mn were significantly increased and reduced by the soil conditioner broadcast. Sulfur spray significantly inhibited Mn uptake but enhanced the accumulation of Mg, Ca, sugars and cyanidin-3-rutinoside in the pericarp, leading to improved fruit pigmentation. Antioxidase activities were regulated to resist Mn stress by sulfur spray. The spray of ascorbic acid could not mitigate DPD as expected, probably due to the dose used. Conclusively, this study provides a practicable approach to mitigate Mn phytoavailability in acid soils. [ABSTRACT FROM AUTHOR]

Foliar nutrient diagnosis is a potent tool for nutrient management in crops. Litchi (Litchi chinensis Sonn.) plantation in China dominates the worldwide litchi cultivation, and Feizixiao is the most widely cultivated species in China. Herein, 538 leaf samples were collected at fruit swelling stage and the terminal shoot maturing stage during 2016–2017, and the fruit yields of all the sampled trees were recorded. The suitability of four nutrient diagnosis methods including critical value approach (CVA), sufficiency range approach (SRA), modified diagnosis and recommendation integrated system (M-DRIS), and compositional nutrient diagnosis (CND) in Feizixiao were compared. Only a few of foliar nutrients could be diagnosed by CVA. Similar evaluations were achieved by both M-DRIS and CND, but the diagnosis accuracy highly varied with the severity of nutrient deficiency or abundance and the diagnosis year. Finally, SRA was accepted to establish the diagnosis norms due to its stable assessments for all nutrients. The optimal foliar nutrient range for Feizixiao is recommended as N 16.7–19.2, P 1.06–1.25, K 5.1–6.7, Ca 7.7–11.0, Mg 2.5–3.7 and S 1.51–1.81 g kg−1, and Zn 19.6–32.6 and B 11.5–19.2 mg kg−1 at the fruit swelling stage , and N 19.7–22.0, P 1.69–1.95, K 10.8–12.7, Ca 3.0–4.1, Mg 2.5–2.9 and S 1.38–1.57 g kg−1, and Zn 15.0–18.9 and B 10.8–16.8 mg kg−1 at the terminal shoot maturing stage. [ABSTRACT FROM AUTHOR]

Roxarsone (ROX), a widely used feed additive, occurs as itself and its metabolites in animal manure. Rice is prone to accumulate As than other staple food. Four diets with 0, 40, 80 and 120mgROXkg(-1) were fed in chickens, and four chicken manures (CMs) were collected to fertilize rice plants in a soil culture experiment. Linear regression analysis shows that the slopes of As species including 4-hydroxy-phenylarsonic acid, As(V), As(III), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA) in CM versus dietary ROX were 0.033, 0.314, 0.033, 0.054 and 0.138, respectively. Both As(III) and DMA were determined in all rice grains, and As(III), As(V), MMA and DMA in rice hull, but detectable As forms in rice straws and soils increased with increasing ROX dose. Grain As(III) was unrelated to ROX dose but exceeded the Chinese rice As limit (0.15mgAs(III)kg(-1)). Dietary ROX enhanced straw As(III) mostly, with the slope of 0.020, followed by hull DMA (0.006) and grain DMA (0.002). The slopes of soil As(V) and As(III) were 0.003 and 0.001. This is the first report illustrating the quantitative delivery of ROX via food chain, which helps to evaluate health and environmental risks caused by ROX use in animal production., (Copyright © 2016 Elsevier B.V. All rights reserved.)