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Understanding soil phosphorus (P) distribution and its key drivers is fundamental for sustainable P management. In this study, a 21-year fertilization experiment on black soil was carried out, setting up five fertilization treatments: unfertilized control (CK), nitrogen and potassium (NK), nitrogen, P and potassium (NPK), NPK plus straw (NPKS), and NPK plus manure (NPKM). The distribution and effecting factors of P pools within soil aggregates were investigated. Compared to CK, the NK and NPK treatments decreased calcium-associated P concentration in all aggregate fractions. Meanwhile, the NPK treatment significantly increased the organic P extracted from NaOH in unaggregated particles (<0.053 mm). This was mainly due to the reduction in soil pH. The NPKS and NPKM treatments increased almost all P forms in aggregates, especially Ca-P. For the NPKM treatment, inorganic P extracted from resin, NaHCO3, and NaOH increased as aggregate size increased. This was mainly because straw or manure addition promoted soil organic carbon (SOC) storage in aggregates, creating more sorption sites via association with amorphous metallic minerals, and, thus, facilitating P accumulation. In conclusion, decreasing soil pH by chemical fertilizers is an effective strategy for mobilizing soil P, whereas increasing SOC by straw or manure facilitates P accumulation. [ABSTRACT FROM AUTHOR]

Plant NAPDH oxidase (NOX) gene family members are critical producers of ROS and play crucial roles in plant signaling, development, and stress responses. Opisthopappus taihangensis is a pivotal wild genetic resource in Asteraceae. To date, little knowledge exists about the functions of NOXs in O. taihangensis. In this study, seven typical NOXs and seven ferric reduction oxidases (FROs) were identified in O. taihangensis. Dispersed duplication might play a critical role in the expansion of the NOX/FRO gene family in O. taihangensis, and most of the NOX/FRO homologous pairs have undergone purifying selection. Although the results of the collinearity analysis show that these genes were relatively conserved, the gain and loss of members in this gene family occurred frequently during the evolution of Asteraceae. Phylogenetic analysis indicated that the FROs are relatively ancient, and the earliest diverged branch was revealed by the maximum likelihood (ML) tree. The Asteraceae NOXs were divided into six subgroups according to their relationship with Arabidopsis and rice members. The transcriptome profile unveiled tissue-specific expression patterns and complex response modes under drought and salt stresses. OtNOX6 and OtNOX7 could be recognized as important candidates to respond to drought and salt stress. Our results provide clues and references for further in-depth exploration of NOX/FRO function in O. taihangensis and other horticulture plants. [ABSTRACT FROM AUTHOR]

Phosphorus (P) leaching from excessive P application is the primary pathway of P losses in agricultural soils. Different P fertilizer practices have mixed effects on P leaching. We conducted a meta-analysis of the relevant literature regarding the response of crop yields, soil-available P (AP), and total P (TP) leaching to reduced P input (RP) and an inorganic-organic combination fertilizer (NPKM) for different agricultural land-use types. Compared to conventional P application (CP), RP (10~90% reduction) did not reduce crop yields in vegetable fields (experiments were 1~4 years) but significantly reduced cereal yields by 4.57%. Compared to chemical fertilizer (NPK), NPKM significantly increased cereal yields by 12.73%. Compared to CP, RP significantly reduced AP at 0~60 cm in vegetable and cereal fields. The greatest reduction occurred at 20~40 cm in vegetable fields (40.29%) and 0~20 cm in cereal fields (34.45%). Compared to NPK, NPKM significantly increased the AP at 0~60 cm in vegetable fields, with the greatest increase (52.44%) at 20~40 cm. The AP at 0~40 cm in cereal fields significantly increased under the NPKM treatment, with the greatest increase at 0~20 cm (76.72%). Compared to CP, RP significantly decreased TP leaching by 16.02% and 31.50% in vegetable and cereal fields, respectively. Compared to NPK, NPKM significantly increased TP leaching in vegetable fields (30.43%); no significant difference in leaching occurred in cereal fields. P leaching, in response to RP, was influenced by the P amounts applied (34.49%); soil organic matter (14.49%); and TP (12.12%). P leaching in response to NPKM was influenced by multiple factors: rainfall (16.05%); soil organic matter (12.37%); soil bulk density (12.07%); TP (11.65%); pH (11.41%). NPKM was more beneficial for improving yields in cereal fields with low soil fertility and lower P-leaching risks. [ABSTRACT FROM AUTHOR]