Abstract
The forms in which phosphorus (P) accumulates in soils are dependent on management practices, fertilizer sources, and methods of application, which may promote distinct P solubility and plant uptake. We aimed here to evaluate how soil tillage and phosphate fertilization strategies affected soil P fractions over 17 years and to identify best management practices for improving labile P fractions. The experiment was conducted in a very clayey Rhodic Ferralsol (Oxisol) with initially very low P availability, during 17 years under soybean and corn, fertilized with 35 kg P ha?1 year?1 . Treatments were two soil management systems (CT-conventional tillage and NT-no-till) and four phosphate fertilization strategies (TSP ? triple superphosphate or RRP ? reactive rock phosphate, applied to the crop furrow or broadcast). Soil samples were taken at five depth layers, and organic (Po), inorganic (Pi), and total P (Pt) were determined by Hedley?s sequential fractionation. CT resulted in a more homogeneous distribution of Pi fractions throughout the soil profile, while under NT there was a steep depth gradient characterized by Pi accumulation in the fertilizer application zone. NT resulted in accumulation of Pi in more labile fractions and higher accumulation of Po physically protected by aggregation, both compared to CT. Also, under NT with RRP, there was a great accumulation of Pi associated with calcium (HCl Pi) compared to TSP, especially when the fertilizer was broadcast applied. An accumulation of Po down to 20 cm (CT) and 10 cm (NT) was also detected, compared to Cerrado natural soil. NT and RRP positively affected legacy P fractions and can be recommended as strategies to improve P fertilizer use efficiency. Keywords: no-tillage, P fractionation, legacy P, P source, P distribution
Highlights
Brazilian Cerrado soils originally present low phosphorus (P) availability for cropping, making the addition of phosphate fertilizers mandatory, firstly to build up P availability to acceptable levels before cropping and secondly to maintain the available levels during subsequent growing seasons, through periodic fertilization to replace the P exported by harvestingDistribution of Soil Phosphorus Fractions (Kurihara et al, 2016)
A high fertilizer P input, at a rate above that exported by the crop harvested products, is demanded when establishing the cropping system under these low initial soil test P (STP) soils, to improve P contents and compensate the soil solid phase P sink, which is significantly higher than plant demand (Novais et al, 2007)
This study aimed to evaluate how soil tillage, phosphate source, and mode of application affected soil P fractions after 17 cropping years in an Oxisol considered highly adsorptive for P
Summary
Brazilian Cerrado (savanna) soils originally present low phosphorus (P) availability for cropping, making the addition of phosphate fertilizers mandatory, firstly to build up P availability to acceptable levels before cropping and secondly to maintain the available levels during subsequent growing seasons, through periodic fertilization to replace the P exported by harvestingDistribution of Soil Phosphorus Fractions (Kurihara et al, 2016). In terms of management practices, soil tillage system (Zheng et al, 2001; Tiecher et al, 2012a,b), the chemical and physical nature of the fertilizer (Zheng et al, 2001; Pavinato et al, 2017), the degree of fertilizer–soil contact (Santos et al, 2008), the rate applied (Zhang et al, 2004; Gatiboni et al, 2007), and the contribution of plant biomass (Tiecher et al, 2012a,b) are the most influential factors. All of these factors, combined, may affect soil legacy P characteristics
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
