The importance of early season phosphorus nutrition

Abstract

. 2001. The importance of early season phosphorus nutrition. Can. J. Plant Sci. 81: 211-224. A review of studies conducted in a range of plant species indicated the importance of an adequate supply of P during early crop growth and outlined plant adaptations for accessing early season P. Potential implications of the requirement for early season P in the development of management practices to optimize P supply for crop production were also discussed. Phosphorus plays a critical role in energy reactions in the plant. Deficits can influence essentially all energy requiring processes in plant metabolism. Phosphorus stress early in the growing season can restrict crop growth, which can carry through to reduce final crop yield. Deficiencies during early growth generally have a greater negative influence on crop productivity than P restrictions imposed later in growth. Plants respond to P deficiencies by adaptations that increase the likelihood of producing some viable seed. The adaptations increase the ability of the plant to access and accumulate P and include modification of rhizosphere pH, diversion of resources to root production, increased root proliferation in high-P regions, and formation of associations with vesicular arbuscular mycorrhizae. Plants differ in strategies adopted and in efficiency of P absorption.Effective nutrient management for optimal crop production must ensure that P is supplied to the crop in adequate amounts early in the growing season. It is important that we develop methods to accurately predict the early season P supply from the soil, in order to avoid either over-fertilization or crop deficiencies. Practices to provide adequate P early in plant growth include placement of P fertilizer in or near the seed-row and maintenance of adequate concentrations of plant-available P in the soil through a long-term nutrient management strategy. Other possible management practices could include enhancement of seed concentrations of P, manipulation of tillage system and crop sequence, improved activity of mycorrhizae and other microbiological agents such as Penicillium bilaii to increase phytoavailability of soil P, or genetic selection of crops with an enhanced ability for early season uptake of P from both soil and fertilizer sources. As plants differ in relative abilities to access P from the soil and fertilizer applications, nutrient management must be tailored to the specific crop, in order to optimize P supply and crop productivity. By restricting fertilizer applications to situations where P supply is limiting to crop production and by use of effective P management practices, we can optimize the economic of fertilizer use while avoiding negative impacts on environmental quality. Une analyse des recherches effectuées sur diverses espèces végétales révèle l'importance d'un apport suffisant de phosphore au début de la période végétative et montre comment les plantes s'adaptent pour trouver le phosphore (P) dont elles ont besoin. Les auteurs ont aussi examiné les conséquences éventuelles de cette...

Crop response to current and previous season applications of phosphorus as affected by crop sequence and tillage

“…La production de biomasse au de´but de la saison et le rendement grainier du lin sont relativement peu affecte´s par les engrais P, qu'ils soient applique´s la saison ante´rieure ou la meˆme saison, bien qu'on note une augmentation de la concentration de P au de´but de la saison et de l'accumulation de P quand le lin est fertilise´avec l'engrais phosphate´. Parmi les facteurs e´value´s dans le cadre de cette e´tude, c'est la culture ante´rieure qui influe le plus sur la croissance du lin, l'e´tablissement de la culture, la production de biomasse en de´but de saison, l'accumulation de P et le rendement grainier connaissant une hausse significative quand on cultive le lin apre`s le ble´plutoˆt qu'apre`s du canola.Mots clé s: Assolement, fertilisation, phosphate d'ammonium diacide, lin, ble´, canola An adequate early-season P supply is critical to obtain optimum crop yield (Grant et al 2001). Withholding P during early plant growth can cause a restriction in crop growth from which the plant may not recover.…”

“…Mots clé s: Assolement, fertilisation, phosphate d'ammonium diacide, lin, ble´, canola An adequate early-season P supply is critical to obtain optimum crop yield (Grant et al 2001). Withholding P during early plant growth can cause a restriction in crop growth from which the plant may not recover.…”

Co-inoculations of arbuscular mycorrhizal fungi and rhizobia under salinity in alfalfa

“…Through many researches, arbuscular mycorrhizal fungi (AMF) have been shown to promote plant growth and salinity tolerance. They promote salinity tolerance by employing various mechanisms, such as enhancing nutrient uptake, especially phosphorus (P) nutrition (Giri et al 2002), producing plant growth hormones, improving rhizospheric condition of the soil (Linderman 1994), altering the physiological and biochemical properties of the host plants (Grant et al 2001) and improving host physiological processes (Pfetffer and Bloss 1988). In addition, AMF colonization can reverse the effect of salinity on potassium (K) and Na + nutrition by enhancing K + absorption under saline conditions (Ruiz-Lozano et al 1996;Giri et al 2002;Sharifi et al 2007) while preventing Na translocation to shoot tissues.…”

Relationship of soil phosphorus fractions to phosphorus soil tests and fertilizer response

“…The lack of a better relationship between soil test P and fertilizer response was attributed to the generally high level of P fertility in Alberta soils and a frequent "starter" benefit of P fertilizer, even on soils testing high in P. Starter benefits of P fertilizer depend on soil temperature and moisture conditions during early growth, as well as crop type and soil P availability (Grant et al 2001). However, some of the unexplained variation in P fertilizer response may have also been due to the use of soil test methods that do not provide an accurate assessment of P availability to plants.…”