Increasing barley production in the face of declining soil fertility on smallholder farms is a critical challenge in Ethiopia. The objectives of this study were to (1) determine the optimum rates of nitrogen (N), phosphorus (P), potassium (K), and sulfur (S) fertilizers under a balanced fertilization of other macro- and micronutrients (zinc and boron) and (2) quantify the agronomic efficiency of N and P on Cambisols and Vertisols. The trials were conducted for three consecutive years (2014–2016) on farmers’ fields on 83 sites under rain-fed conditions. On each farm, six rates of N, P, K, and S with a balanced application of the other nutrients were laid out separately in a randomized block design with three replicates. Balanced fertilization resulted in yield increments of 26–59% on Cambisols and 18–74% on Vertisols, as compared with the control (0 N). Application of P increased grain yield from 11% to 30% and from 7% to 14% due to the interaction of P by soil type as compared with the control. The application of K and S, however, had no significant effect on barley yields on either soil type. The highest agronomic efficiency of N (AEN) was obtained from 46 kg N ha−1, with AEN increasing by 117% on Cambisols and 33% on Vertisols, as compared with the highest N rate of 230 kg N ha−1. The maximum agronomic efficiency of P (AEP) was recorded with 10 kg P ha−1 on Vertisols, with AEP increasing by 73% on Cambisols and 452% on Vertisols, as compared with the application of 50 kg P ha−1. With balanced application of other nutrients, use of 230 kg N and 20 kg P ha−1 was recommended for tepid sub-moist mid-highlands and Vertisols. For tepid sub-humid mid-highlands, application of 46 kg N and 20 kg P ha−1 with balanced application of other nutrients was recommended. For Cambisols, application of 230 kg N and 40 kg P ha−1 was recommended with balanced application of the other nutrients. Similarly, application of 230 kg N, 40 kg P, and 10 kg S ha−1 was tentatively recommended for cool sub-most mid highlands. However, response to K was inconsistent and therefore a firm recommendation could not be proposed for the study sites. Further research needs to be conducted on more soil types and locations.

面对小农农场土壤肥力下降，增加大麦产量是埃塞俄比亚面临的一项重大挑战。本研究的目的是 (1) 确定氮 (N)、磷 (P)、钾 (K) 和硫 (S) 肥料在其他宏量和微量营养素（锌和硼）的平衡施肥下的最佳施用量) 和 (2) 量化 N 和 P 在 Cambisols 和 Vertisols 上的农艺效率。这些试验连续三年（2014-2016 年）在雨养条件下的 83 个地点的农田上进行。在每个农场，N、P、K 和 S 的六种比例与其他营养素的均衡应用分别以随机区组设计进行布局，三个重复。平衡施肥导致 Cambisols 产量增加 26-59%，Vertisols 产量增加 18-74%，与对照（0 N）相比。与对照相比，由于土壤类型与磷的相互作用，磷的施用使谷物产量从 11% 提高到 30%，从 7% 提高到 14%。然而，K 和 S 的施用对两种土壤类型的大麦产量没有显着影响。N (AEN) 的最高农艺效率来自 46 kg N ha-1 ，与 230 kg N ha -1的最高 N 比率相比，Cambisols 的 AEN 增加了 117%，Vertisols 的 AEN 增加了 33% 。与施用 50 kg P ha -1相比，在 Vertisols 上使用 10 kg P ha -1记录了 P (AEP) 的最大农艺效率，在 Cambisols 上 AEP 增加了 73%，在 Vertisols 上增加了 452% 。在平衡应用其他养分的情况下，建议对不温不火的亚湿润中高地和 Vertisols使用 230 kg N 和 20 kg P ha -1 。对于不温不火的半湿润中高地，建议施用 46 kg N 和 20 kg P ha -1并平衡施用其他养分。对于 Cambisols，施用 230 kg N 和 40 kg P ha -1建议均衡应用其他营养素。同样，对于凉爽的次中部高地，初步建议施用 230 kg N、40 kg P 和 10 kg S ha -1 。然而，对 K 的反应不一致，因此无法为研究地点提出明确的建议。需要对更多的土壤类型和位置进行进一步的研究。