[Effects of reducing chemical fertilizers combined with organic fertilizers on soil microbial community in litchi orchards]. / å‡æ–½åŒ–è‚¥é æ–½æœ‰æœºè‚¥å¯¹è”æžå›­åœŸå£¤å¾®ç”Ÿç‰©åŒºç³»çš„å½±å“.

Organic fertilizer application can replace a part of chemical fertilizer (CF) to improve the quality and efficiency of litchi production. To further explore the soil microbiological mechanism, with 19-year-old 'Feizixiao' litchi trees as the research objects, we examined the effects of two consecutive years of reduced CF applications (average 21.5% of total nutrients) combined with sheep manure (OF) and bio-organic fertilizers (BIO) on soil microbial diversity, community composition and differential microorganisms. The results showed that reducing the application of chemical fertilizers and combining it with the application of sheep manure and bio-organic fertilizer for two consecutive years could significantly improve yield and quality. The average increase of yield in the two years was 23.1% and 39.0%, respectively. Soil organic matter content and pH increased significantly in response to the combination treatments. Compared to that in the chemical fertilizer treatment, the contents of soil available phosphorus, potassium, calcium, magnesium, iron, manganese, copper, and zinc displayed an increasing trend in the combination treatments. The application of organic fertilizer increased the diversity of bacteria and fungi in rhizosphere soil, but not in non-rhizosphere soil. Both treatments significantly changed soil microbial community structure, increased eutrophic bacterial groups such as Bacteroides, Proteobacteria, and Bacillus phylum, and reduced anatrophic bacterial groups such as Acidobacteria and Chloroflexus. Compared with CF, the relative abundances of MND1 under OF and TK10, Gemmatimonas, Pseudolabrys, Trichoderma and Botryotrichum under BIO were significantly increased, which was positively correlated with yield. In conclusion, reducing CF and applying organic ferti-lizer for two consecutive years could effectively improve soil pH and nutrient availability, increase rhizosphere microbial richness and diversity, change soil microbial community structure, and shape microbial communities being more conducive to yield and quality improvement.

[Effects of phosphorus fertilizer application methods and types on the yield and phosphorus uptake of winter wheat.] / ç£·è‚¥æ–½ç”¨æ–¹å¼åŠç±»åž‹å¯¹å†¬å°éº¦äº§é‡å’Œç£·ç´ å¸æ”¶çš„å½±å“.

A field micro-plot experiment was conducted to determine the effect of different placement methods and types of phosphorus (P) fertilizer on winter wheat growth and phosphorus uptake. P fertilizer types included monocalcium phosphate (MCP) and diammonium phosphate (DAP). P fertilizer application methods included: 1) surface broadcasting (S); 2) banding 5 cm below seeds (B0); 3) banding 5 cm below and 3 cm away from seeds (B3); 4) banding 5 cm below and 10 cm away from seeds (B10); 5) mixing with the 20% of the top soil below seeds (M). The result showed that B0 had the best effect on increasing yield, reached 7.63 t·hm-2 in MCP-B0 and 7.99 t·hm-2 in DAP-B0, which increased 10.3% and 10.7%, respectively compared with surface broadcasting. B10 had the lowest grain yield (6.60-6.77 t·hm-2). The total P uptake by wheat in B0 and M was at a relatively high level (34.42-35.60 kg·hm-2), B10 performed worst at all growth stages of wheat, while P uptake of DAP-B10 was 11.9% higher than MCP-B10. These results indicated that concentrating P fertilizer in a short distance near the seeds was an optimized application method for winter wheat in this region, and DAP performed better than MCP on P uptake and utilization of wheat under far banding.