Nitrate loss from a tile-drained reclaimed marsh soil from SW Spain amended with different products

Abstract

Tile drainage and soil amendments have been found to affect losses of nitrate N from agricultural soils. This work was aimed at measuring nitrate N losses in a tile-drained marsh soil from SW Spain under traditional fertilization and irrigation practices, and how these losses were influenced by the application of soil amendments. To this end, a randomised block experiment with three replications was performed during two consecutive growing seasons-2003 to 2004 with cotton and sugar beet, respectivelyinvolving four different amendment treatments: (1) control without amendment, (2) phosphogypsum (PG), (3) manure, and (4) sugar factory refuse lime (SFRL). Flow-weighted (FW) nitrate-N concentrations in drainage water, estimated as the slope of the regression of the instantaneous nitrate-N flow as a function of drain flow rate, was decreased by PG in some drainage events in the 2003 season and in the four last events of the 2004 season when compared with control without amendment. The increased FW nitrate-N concentrations in drainage from SFRL in comparison to control in a drainage event of 2003 season, and in the four last events of 2004, can be explained by the contribution of N present in the amendment. These effects did not account for significant differences in nitrate-N loss among treatments over the whole season in 2003, when they ranged from 19.3 to 24.9 kg N ha -1 , accounting for 6-8% of applied N, nor in 2004, when they ranged from 4 to 6 kg N ha -1 , accounting for 3-4% of applied N. The decrease in mean FW nitrate-N concentration after the third drainage event in 2003 was not the consequence of the depletion of total soil nitrate-N because soil mineral N was increased on average by 205 kg N ha -1 during the season. The high N extractions by sugar beet and the subsequent decrease in total soil nitrate-N can contribute to explain the decrease of mean FW nitrate-N concentrations along the 2004 season. Greater absolute nitrate-N loss in 2003 than in 2004 was explained by the lower efficiency of the furrow irrigation when compared with sprinkler irrigation. Results also revealed that traditional management of N fertilizer was inadequate: rates applied to cotton were excessive, increasing the risk of N losses not only during the cotton season, but also at the beginning of the following season.Keywords Drainage Á Furrow Á Sprinkler Á Nitrate Á Phosphogypsum Á Manure María Dolores Hurtado died in February 2010. The present work was a part of her unfinished Ph. D. Thesis. Her colleagues and friends wish to dedicate this article to her memory.

Phosphogypsum amendments and irrigation with acidulated water affect tomato nutrition in reclaimed marsh soils from SW Spain

“…The highest rate mimics the cumulative effect of a typical application during 20-30 years in the area. Phosphogypsum (from a non-active stack in Huelva, Spain, disposal site) properties are described elsewhere (Enamorado et al, 2009;Hurtado et al, 2011a). Total nutrient contents of PG were (all in g kg -1 ): P (3.5), S (150), Ca (229), B (3.1), Fe (0.4), Cu (0.0052), Mn (0.0003), Zn (0.011), Ni (0.012) and Mo (0.0009); beside this, its content in Na was 0.3 g kg -1 ; the content of N, K and Mg was not detectable.…”

Implications for food safety of the uptake by tomato of 25 trace-elements from a phosphogypsum amended soil from SW Spain

“…Also, it can supply S and P to crops. Studies have been conducted, among others, on the effect of PG applying on the improvement of soil structure, salt balance and crop yield [2][3][4], control of soil erosion [5], availability of S and P [6], and N balance on reclaimed drained soils [7]. Thus, it can be supposed that agriculture could become the main worldwide sink of PG.…”

“…Since the last sixties, this PG was crucial in the reclamation of the saline-sodic marshlands from SW Spain [4,[20][21][22] where it was applied as Ca-amendment at a usual rate of 25 Mg ha −1 (wet weight, after being sun-dried, and with typical remaining water content of 20%). This amendment was essential to achieve a reduction of Na saturation and improvements of physical properties in soil [6,7,23]. On the other hand, there are evidences of significant enrichment of 226 Ra in the surface horizon of reclaimed soils plots relative to the deeper horizons and Cd in tomatoes produced in the area with higher concentrations than those found in tomatoes from other origins in Spain [1,9].…”

Influence of external drivers on water use efficiency and sustainability in agricultural production

“…Indeed, the agricultural practices could bear improvements with regard to the environment. Hurtado et al (2011) estimated the nitrogen losses from the lower Guadalquivir area with artificial drainage under cotton cultivation in 2003, reporting that 6-8% of applied nitrogen is lost and suggesting inadequate nitrogen management for this typical fertilisation behaviour. Santos et al (2010) studied an irrigation scheme in the basin in detail and report a varying acceptance of the recommendations from the irrigation advisory service by farmers, leading to varying efficiencies in irrigation performance, both over-and under-satisfying crop water requirements.…”