OsABF1 mediates drought tolerance by directly up-regulating the expression of drought-associated genes, including COR413-TM1, and forms a complex feedback circuit in the drought/abscisic acid signaling pathway.

The purpose of this study was to clarify the effects of biochar on the diversity of bacteria and fungi in the rice root zone and to reveal the changes in soil microbial community structure in the root zone after biochar application to provide a scientific basis for the improvement of albic soil. Rice and corn stalk biochar were mixed with albic soil in a pot experiment. Soil samples were collected at the rice maturity stage, soil nutrients were determined, and genomic DNA was extracted. The library was established using polymerase chain reaction (PCR) amplification. The abundance, diversity index, and community structure of the soil bacterial 16SrRNA gene V3 + V4 region and the fungal internal transcribed spacer-1 (ITS1) region were analyzed using Illumina second-generation high-throughput sequencing technology on the MiSeq platform with related bioinformatics. The results revealed that the biochar increased the soil nutrient content of albic soil. The bacteria ACE indexes of treatments of rice straw biochar (SD) and corn straw biochar (SY) were increased by 3.10% and 2.06%, respectively, and the fungi ACE and Chao indices of SD were increased by 7.86% and 14.16%, respectively, compared to conventional control treatment with no biochar (SBCK). The numbers of bacterial and fungal operational taxonomic units (OUT) in SD and SY were increased, respectively, compared to that of SBCK. The relationship between soil bacteria and fungi in the biochar-treated groups was stronger than that in the SBCK. The bacterial and fungal populations were correlated with soil nutrients, which suggested that the impacts of biochar on the soil bacteria and fungi community were indirectly driven by alternation of soil nutrient characteristics. The addition of two types of biochar altered the soil microbial community structure and the effect of rice straw biochar treatment on SD was more pronounced. This study aimed to provide a reference and basic understanding for albic soil improvement by biochar, with good application prospects.

Soil salinity and alkalinity are key abiotic stresses that limit crop growth and yield worldwide. Balanced N fertilization is important for improving rice (Oryza sativa L.) yield via efficient utilization of P and K under saline and alkaline soil conditions. In this study, a japonica rice cultivar, Kenjing 8, was used to investigate the effects of N fertilizer on rice yield, as well as N, P, and K status, in a 2‐yr field experiment in saline‐alkaline soil in Heilongjiang Province, northeast China. The plants were assigned to the following five treatment groups: no N fertilizer, or conventional, balanced, reduced, and postponed N fertilizer management. Compared with conventional N management practice, balanced and reduced N management practices increased the concentrations of N, P, and K in the leaves, stem‐sheaths, and panicles at full heading (FH) and maturity; however, postponed N management led to the opposite results. Balanced N management increased N, P, and K mobilization to the leaves (from FH to maturity) by 49, 43, and 67%, respectively, resulting in the highest crop yields among all the N management practices studied. Furthermore, rice yield was positively correlated with N, P, and K accumulation and rates of nutrient mobilization to the leaves, stem‐sheaths, and panicles at maturity. The application of 150 or 135 kg N ha−1, and the proportion of 4:3:1:2 in the pre‐transplanting, mid‐tillering, panicle initiation, and panicle differentiation stages, may increase rice yield and facilitate efficient utilization of nutrients in saline‐alkaline soil.

Integrated crop management practices can improve rice (Oryza sativa L.) grain yield, but the effects of such practices on dry matter accumulation and photosynthetic productivity are inconsistent and not well understood. The primary objective of this study was to investigate the effects of integrated crop management practices on dry matter accumulation and redistribution, photosynthetic production, and yield of rice in northeast China. Medium‐ and high‐yielding potential japonica rice cultivars were grown using four crop management practices, including no N application (N0), local farmers’ cultivation practice (FP), high‐yield cultivation practice (HYP), and super‐high‐yield cultivation practice (SHYP). The increases in average yield with the HYP and SHYP treatments were 16.87 and 36.70%, respectively, in 2017 and 14.70 and 31.05%, respectively, in 2018, compared with FP. Increases in effective panicle number and spikelet number per panicle were the main reason for the increase in yield under the integrated crop management treatments. Compared with FP, the HYP and SHYP treatments significantly increased the population dry matter by 26.40 and 56.64%, respectively, before the heading stage. Relative to N0 and FP, HYP and SHYP significantly increased the dry matter export, export rate, and translocation rate in the leaves, stems, and sheaths and significantly increased the photosynthetic potential throughout the growth stage and the net assimilation rate after the tillering stage. These increases were critical for improving the quality of rice and achieving higher yields. Our study provides a theoretical basis for the development of high‐yield cultivation methods for rice in northeast China.

Direct seeding of rice has emerged as a strategy for sustainable rice (Oryza sativa L.) production because of advantages, such as fewer production links, labor and farmland water-saving, easy mechanization, and high economic benefits. However, few studies have investigated the effects of different organic fertilizers on soil fungal community and rice yield in dry direct-seeded paddy fields. In order to select the best combination of organic fertilizer and chemical fertilizer, field experiments were used to evaluate the role of no fertilizer (F0); CF, conventional NPK fertilizer, OF1, biochar + conventional NPK fertilizer; OF2, seaweed bioorganic fertilizer + conventional NPK fertilizer; OF3, Jishiwang bioorganic fertilizer + conventional NPK fertilizer; and OF4, attapulgite organic fertilizer + conventional NPK fertilizer on microbial structure and diversity and rice yield. Under Jishiwang bioorganic fertilizer + conventional NPK fertilization, the number of fungal OTUs was 365 and ranged from 1 to 9. The Ascomycota relative abundance was increased by 28.25% under Jishiwang bioorganic fertilizer application compared with CF, but the Basidiomycota decreased. Sordariomycetes and Leotiomycetes relative abundances were increased under organic fertilization. The relative abundance of dung saprotrophs, fungal parasites, and leaf saprotrophs was increased under organic fertilizer compared to CF, and animal pathogens decreased, but organic fertilizers also increased plant pathogens. Rice yield was increased under Jishiwang bioorganic fertilizer + conventional NPK fertilizer and was positively correlated with Ascomycota and Sordariomycetes relative abundances. The use of Jishiwang bioorganic fertilizer + conventional NPK fertilizer improves fungal community diversity and rice yield.

Applying appropriate agronomic practices instead of conventional farming practices might improve rice yield. However, few studies have focused on how integrated agronomic practices affect N, P, and K accumulation and allocation in rice (Oryza sativa L.). Therefore, this study was conducted to investigate grain yield, N, P, and K accumulation, and allocation under different agronomic practices. A japonica rice cultivar was grown in the field, with four agronomic practice treatments: no N application (N0), local farmers' practice (FP), high-yield practice (HYP), and super-high-yield (SHY) practice. The results showed that the latter two practices significantly increased grain yield by 11.0% and 26.4%, respectively, compared with that under FP, mainly as a result of an increase in mean number of panicles m −2 and spikelets panicle −1 . Mean aboveground N, P, and K accumulation significantly increased by 24.9, 15.3, and 79.1%, in HYP and 42.0, 38.8, and 219.7% in SHY, respectively, compared with that under FP. In particular, K accumulation was higher than N and P accumulation in HYP and SHY plants than those in FP plants. However, N, P, and K grain productivity was lower by 7. 5, 9.5, and 20.3% under HYP, and 20.3, 17.2 and 62.7% under SHY treatments than that of FP, respectively, and N, P, and K grain productivity were negatively correlated with yield. Our results suggest that an increase in N, P, and K accumulation from the full-heading stage (FH) to the maturity stage (MS) may assist with improving rice yields under HYP and SHY treatments. 1238wileyonlinelibrary.com/journal/agj2

No abstract

The effects of biochar application on dry direct-seeded rice paddies remains unclear. Therefore, we applied biochar to dry direct-seeded rice paddy fields over 3 consecutive years to assess its effects on soil physicochemical properties and bacterial diversity (conventional fertilization [CK]; biochar + conventional fertilization [BC]). BC increased the content of 0.25–5 mm soil water-stable aggregate particles, but decreased that of <0.25 mm soil water-stable aggregates. At different soil depths, BC significantly reduced sand content and increased silt content. Compared to CK, BC significantly increased the available phosphorus and potassium content of the 0–10 and 10–20 cm soil layers. There were no significant differences in pH, organic matter, total nitrogen, total phosphorus, or total potassium content between the treatments at different soil depths. Compared to CK, BC significantly increased soil neutral phosphatase and catalase activities. Furthermore, BC significantly increased bacterial richness, but had no significant effect on bacterial diversity. According to Qualcomm sequencing analysis, BC increased the relative abundance of Verrucomicrobia, Chloroflexi, Bacteroidetes, Nitrospirae, Verrucomicrobiae, Blastocatellia_Subgroup_4, and Anaerolineae in soil compared to CK. The soil bacterial genera in BC had stronger interrelationships than those in CK. According to redundancy analysis, organic matter was the main environmental factor influencing bacterial community structure. Overall, biochar could promote soil nutrient conversion in dry direct-seeded rice paddies, improve soil effective nutrient content, change the composition of soil bacterial communities, and increase soil bacterial richness. Applying biochar in dry direct-seeded rice cultivation could help realize low-carbon agriculture.