Soil testing guidelines for sulfur (S) under dryland cropping in south-eastern Australia are not well developed. Our objective was to assess the value of soil and tissue tests for S and nitrogen (N), because the two minerals frequently interact), in predicting S-deficient sites and hence increasing the probability of response to application of S (and N). Here, we report three proximal experiments in 2014–16 for barley (Hordeum vulgare L.) and wheat (Triticum aestivum L.) on a sandy soil in a semi-arid environment near Merriwagga in western New South Wales. The trials contained a factorial combination of four rates of each of applied N as urea and S as high-grade gypsum.

Responses to S were obtained for dry matter (DM) quantity and nutrient content at flowering in 2014, but no grain-yield response was obtained in any year. DM response to applied S was obtained when the concentration of S in the DM was increased from 0.08% in barley and 0.09% in wheat without S application to 0.10–0.11% in both crops with S applied as gypsum. Because we obtained no grain-yield responses to applied S, the 0.10% S in grain was likely to have been adequate for both crops in these experiments. A pool of subsoil S was accessed during each season and this compensated for any DM deficiencies of S by the time of grainfill. Shallow soil tests (0–10 cm) for S can therefore indicate sufficiency but not necessarily deficiency; therefore, in grain-cropping areas, we recommend soil S tests on the same samples as used for deep N testing (to 60 cm) and that an S-budgeting approach be used following the soil tests. Furthermore, for marginal nutritional circumstances such as occurred in this study, the supporting use of N : S ratio is recommended, with values >17 in DM or grain likely to indicate S deficiency for both barley and wheat.

在澳大利亚东南部干旱地区种植的土壤中硫（S）的土壤测试指南尚未完善。我们的目标是评估土壤和组织测试中S和N（N）的价值，因为这两种矿物质经常相互作用）在预测S缺乏的部位时，从而增加了对施用S（和N）的反应可能性。在这里，我们报告了2014-16年度在新南威尔士州西部Merriwagga附近半干旱环境中的沙质土壤上的大麦（Hordeum vulgare L.）和小麦（Triticum aestivum L.）的三个近端实验。该试验包含四种比例的因子分解组合，每种比例施用的N作为尿素，S作为高等级石膏。

2014年开花时对干物质（DM）的数量和养分含量对S的响应，但在任何一年中均未获得籽粒产量的响应。当DM中的S浓度从大麦中的0.08％和不施用S的小麦中的0.09％增加到两种以S施用石膏的农作物中的0.10–0.11％时，DM对施用的S的反应均获得。由于我们没有获得对施用S的籽粒产量的响应，因此在这些实验中，两种作物的籽粒中0.10％的S可能已经足够。在每个季节都进入了一个地下土壤S的池，这可以在填谷之前弥补S的任何DM不足。因此，对S进行浅层土壤测试（0–10 cm）可以表明足够，但不一定不足。因此，在谷物种植区，我们建议在与用于深氮测试（至60厘米）的样品相同的样品上进行土壤S测试，并在土壤测试后使用S预算法。此外，对于本研究中出现的边缘营养情况，建议支持使用N：S比率，DM或谷物中的值> 17可能表明大麦和小麦都缺乏S。