Carbon–Phosphorus Coupling Governs Microbial Effects on Nutrient Acquisition Strategies by Four Crops

Abstract

Plants adjust root morphological and/or exudation traits in response to phosphorus (P) mobilization mediated by microorganisms. We hypothesized that straw application coupled with P fertilization would influence microbial P and then root nutrient-acquisition strategies related to crop growth. Root morphological (length and average diameter) and exudation traits (acid phosphatase and carboxylates) of Brassica chinensis, Solanum lycopersicum, Lactuca sativa, and Vigna unguiculata in response to microbial P dynamics were characterized in no-P and P-fertilized soil with/without straw addition. Straw addition increased the growth of fungi and bacteria, stimulating microbial P immobilization at day 24. The high microbial abundance was associated with four tested crops having short roots in straw-amended compared with no-straw soil at day 24. In straw-amended soil, B. chinensis and S. lycopersicum shifted toward root P-acquisition strategies based on fast elongation and strong carboxylate exudation from days 24 to 40. Such effective root P-acquisition strategies together with microbial P release increased shoot P content in S. lycopersicum in straw-amended compared with those without straw at day 40. Conversely, L. sativa and V. unguiculata produced short roots in response to the stable (or even increased) microbial P after straw addition till day 40. In straw-amended soil, high P application stimulated root elongation and carboxylate exudation in L. sativa and V. unguiculata, whereas carboxylate exudation by S. lycopersicum was decreased compared with the straw-amended but non-fertilized treatment at day 40. In summary, root P-acquisition strategies in response to microbial P differed among the tested crop species. Phosphorus fertilization needs to be highlighted when returning straw to enhance P-use efficiency in vegetable cropping systems.

Metagenomics of the Effect of Long-Term Straw Return on the Phosphorus Cycle in Meadow Black Soil

“…Second, returning crop straw to the field increases soil carbon content, maintains microbial activity, stimulates proliferation, reduces root exudate assimilation, increases bacteria and fungi related to the P cycle, enhances soil microbial diversity, and improves soil phosphate dissolution rate, leading to a higher cumulative P turnover rate [33]. Straw returning over time can enhance soil AP and TP content, with varying effects on various P components [21,29,30,[33][34][35][36][37]. In addition, different levels of straw returned to the field significantly affect soil P content, with a small amount being more effective in changing P dynamics than other treatments [38][39][40], and it significantly stimulates the activity of phosphatase, thereby increasing the mineralization rate of organic P and ultimately increasing the AP content for plants in the soil [29].…”

“…In addition, different levels of straw returned to the field significantly affect soil P content, with a small amount being more effective in changing P dynamics than other treatments [38][39][40], and it significantly stimulates the activity of phosphatase, thereby increasing the mineralization rate of organic P and ultimately increasing the AP content for plants in the soil [29]. Therefore, straw return is crucial for improving soil P accumulation, reducing P fertilizer use, and enhancing agricultural management efficiency [22,30,35].…”

Long-term fertilization has different impacts on bacterial communities and phosphorus forms in sugarcane rhizosphere and bulk soils under low-P stress

“…In addition to the role of plants, which can excrete acid phosphatase (ACP) and other enzymes, microorganisms, including bacteria and fungi, also play an important role in soil P cycling by excreting enzymes such as alkaline phosphatase and ACP (Zhang et al, 2021). In particular, phosphate-solubilizing bacteria (PSB) are of great importance because they are a special group of microorganisms that can dissolve P in soils (Krey et al, 2013;Zhang et al, 2022). Generally, the abundance of PSB or the genes involved in P metabolism is relatively high in P-limited environments due to selection pressures (Dai et al, 2018;Pastore et al, 2020;Ran et al, 2021).…”