![Influence of no-tillage on the distribution and lability of phosphorus in Finnish clay soils [An article from: Agriculture, Ecosystems and Environment]](https://www.ebooknetworking.net/books/B00/0PD/bigB000PDT5Q2.jpg)
Influence of no-tillage on the distribution and lability of phosphorus in Finnish clay soils [An article from: Agriculture, Ecosystems and Environment]
Book Details
PublisherElsevier
ISBN / ASINB000PDT5Q2
ISBN-13978B000PDT5Q7
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Sales Rank99,999,999
MarketplaceUnited States 🇺🇸
Description
This digital document is a journal article from Agriculture, Ecosystems and Environment, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.
Description:
No-tillage (NT) is a method adopted to reduce erosion and particulate phosphorus (P) load from arable land to watercourses. However, it has been found to increase the loss of dissolved P with surface runoff, but the reasons for that have rarely been examined in detail. The objective of the present study was to determine the chemical factors explaining this response by investigating the impact of NT on the type and distribution of P reserves as well as on organic carbon (C) in the 0-35cm topsoil layer of clay soil profiles (Vertic Cambisols). Soil samples were taken from two experimental fields (Jokioinen and Aurajoki) at 0-5, 5-20 and 20-35cm depths in conventionally tilled (CT) and non-tilled (for 4-5 years) plots. The plots had been cultivated and fertilized according to the common field practices in Finland (15-18kgP and 100-128kgNha^-^1year^-^1). Inorganic and organic P reserves characterized by a modified Chang and Jackson fractionation procedure were not significantly affected by the cultivation methods. However, in the uppermost soil layer (0-5cm) in NT of the Jokioinen field, the labile P determined by water extraction (P"w) increased significantly, whereas the increase in P extracted with acid ammonium acetate (P"A"A"C) remained statistically insignificant. The increase in labile P coincided with a significant increase in organic carbon (C), which supports the theory that competition between organic anions and phosphate for the same sorption sites on oxide surfaces will enhance the lability of soil P. In the Aurajoki field with distinct soil cracking, P"w and P"A"A"C were not affected by NT in the uppermost soil layer, but they increased in the deepest soil layer (20-35cm) concomitantly with an increase in Al-bound P and organic C. However, the increases were not statistically significant. In both fields, soil acidification due to the repeated application of N fertilizers at a shallow soil depth as well as the accumulation of organic C lowered pH of the uppermost soil layer in NT compared to the deeper soil layers. The results indicated that even short-term NT can increase the labile P in clay soil. However, further studies are needed to assess the long-term changes in lability of surface soil P and, consequently, the possible need for readjustment of the fertilization level in NT.
Description:
No-tillage (NT) is a method adopted to reduce erosion and particulate phosphorus (P) load from arable land to watercourses. However, it has been found to increase the loss of dissolved P with surface runoff, but the reasons for that have rarely been examined in detail. The objective of the present study was to determine the chemical factors explaining this response by investigating the impact of NT on the type and distribution of P reserves as well as on organic carbon (C) in the 0-35cm topsoil layer of clay soil profiles (Vertic Cambisols). Soil samples were taken from two experimental fields (Jokioinen and Aurajoki) at 0-5, 5-20 and 20-35cm depths in conventionally tilled (CT) and non-tilled (for 4-5 years) plots. The plots had been cultivated and fertilized according to the common field practices in Finland (15-18kgP and 100-128kgNha^-^1year^-^1). Inorganic and organic P reserves characterized by a modified Chang and Jackson fractionation procedure were not significantly affected by the cultivation methods. However, in the uppermost soil layer (0-5cm) in NT of the Jokioinen field, the labile P determined by water extraction (P"w) increased significantly, whereas the increase in P extracted with acid ammonium acetate (P"A"A"C) remained statistically insignificant. The increase in labile P coincided with a significant increase in organic carbon (C), which supports the theory that competition between organic anions and phosphate for the same sorption sites on oxide surfaces will enhance the lability of soil P. In the Aurajoki field with distinct soil cracking, P"w and P"A"A"C were not affected by NT in the uppermost soil layer, but they increased in the deepest soil layer (20-35cm) concomitantly with an increase in Al-bound P and organic C. However, the increases were not statistically significant. In both fields, soil acidification due to the repeated application of N fertilizers at a shallow soil depth as well as the accumulation of organic C lowered pH of the uppermost soil layer in NT compared to the deeper soil layers. The results indicated that even short-term NT can increase the labile P in clay soil. However, further studies are needed to assess the long-term changes in lability of surface soil P and, consequently, the possible need for readjustment of the fertilization level in NT.
