Assessment of sulphur deficiency in commercial oilseed rape crops from plant analysis

Abstract

International audienceSulphur (S) is one of the six main macroelements required to sustain the growth of plants. Sources include soil, fertilizer and atmospheric deposition, which has been reduced by 85% over the last three decades. Risks of S deficiencies are now recognized in high S-demanding species such as Brassica napus L. With the aims of evaluating the risk of excessive or insufficient fertilization and identifying robust relationships that may be used as plant S status indicators, 57 commercial crops of oilseed rape were selected among contrasting soils and along a rainfall gradient that may affect soil S availability. Cultivation practices were investigated and the S and nitrogen (N) concentrations of soil, senescing leaves, stems and seeds were analysed. Despite an excessive organic N supply and large variation in S supply (from 0 to 112 kg S/ha), principal component analysis using 43 parameters indicated that seed yield was poorly related to N and S fertilization rates. While the N and protein-N concentrations in seeds were inversely related to oil and glucosinolate concentrations, they were linked to S and sulphate (SO42-) accumulation in the seeds. Sulphate concentrations in senescing leaves, stems or seeds could be deduced from total S concentrations, as they were positively and highly correlated. Sulphate accounted for on average 0 69 of total S in senescing leaves with minimum and maximumvalues of 0 007 and 0 94, which revealed conditions of limited and excess supply of S, respectively. This high variation of SO42- concentration in leaves can be interpreted as the result of its mobilization triggered by S deficiency, but cannot be used alone as an indicator of plant S status. A comparison with plants grown in controlled conditions under different S supplies suggests that the intensity of S starvation affects N metabolism, leading to NO3-(nitrate) accumulation. It is further suggested that dual evaluation of SO42- and NO3- concentrations in senescing leaves could be used at the vegetative stage as a field indicator to adjust S fertilization

Non-Specific Root Transport of Nutrient Gives Access to an Early Nutritional Indicator: The Case of Sulfate and Molybdate

“…The experimental site was selected from a previous study [39] showing an S deficiency in B . napus L. grown in 2009.…”

Macro and Micronutrient Storage in Plants and Their Remobilization When Facing Scarcity: The Case of Drought

“…For example, S is usually recognized as showing variable mobility [49]. In fact, the S content itself in tissues is highly variable and can be correlated with SO 4 2− content, which may account for more than 80% of total S in leaves of field grown B. napus [50]. As a consequence, when facing S deficiency, plant growth can be sustained for several weeks [51], provided that enough SO…”

Assessment of Sulfur Deficiency under Field Conditions by Single Measurements of Sulfur, Chloride and Phosphorus in Mature Leaves

“…The experimental site was selected from a previous study [ 10 ] showing an S deficiency in Brassica napus L. grown in 2009. This field of 11.3 ha was located at Ondefontaine, France (48°59′18.69” N, 00°41′56.70” W).…”

“…Seed yield from oilseed rape is usually improved by S fertilization, with doses depending on the multiple environment factors under which the crop is being grown [ 9 ]. Consequently, a precise recommendation for S fertilization is difficult, resulting in a wide variation in S doses applied under production conditions from 0 to 112 kg·S·ha −1 [ 10 ]. Consequently, S indicators are needed for an appropriate use of fertilizers and to avoid cases of excessive fertilization having environmental and economic consequences, and particularly to avoid cases of S deficiency so as to prevent losses of yield and seed quality [ 6 , 7 ].…”