Cassava-maize intercropping is a common practice among smallholder farmers in Southern Nigeria. It provides food security and early access to income from the maize component. However, yields of both crops are commonly low in farmers’ fields. Multi-locational trials were conducted in Southern Nigeria in 2016 and 2017 to investigate options to increase productivity and profitability through increased cassava and maize plant densities and fertilizer application. Trials with 4 and 6 treatments in 2016 and 2017, respectively were established on 126 farmers’ fields over two seasons with a set of different designs, including combinations of two levels of crop density and three levels of fertilizer rates. The maize crop was tested at low density (LM) with 20,000 plants ha⁻¹ versus high density (HM) with 40,000 plants ha⁻¹. For cassava, low density (LC) had had 10,000 plants ha⁻¹ versus the high density (HC) with 12,500 plants ha⁻¹.; The fertilizer application followed a regime favouring either the maize crop (FM: 90 kg N, 20 kg P and 37 kg K ha⁻¹) or the cassava crop (FC: 75 kg N, 20 kg P and 90 kg K ha⁻¹), next to control without fertilizer application (F0). Higher maize density (HM) increased marketable maize cob yield by 14 % (3700 cobs ha⁻¹) in the first cycle and by 8% (2100 cobs ha⁻¹) in the second cycle, relative to the LM treatment. Across both cropping cycles, fertilizer application increased cob yield by 15 % (5000 cobs ha⁻¹) and 19 % (6700 cobs ha⁻¹) in the FC and FM regime, respectively. Cassava storage root yield increased by 16 % (4 Mg ha⁻¹) due to increased cassava plant density, and by 14 % (4 Mg ha⁻¹) due to fertilizer application (i.e., with both fertilizer regimes) but only in the first cropping cycle. In the second cycle, increased maize plant density (HM) reduced cassava storage root yield by 7% (1.5 Mg ha⁻¹) relative to the LM treatment. However, the negative effect of high maize density on storage root yield was counteracted by fertilizer application. Fresh storage root yield increased by 8% (2 Mg ha⁻¹) in both fertilizer regimes compared to the control without fertilizer application. Responses to fertilizer by cassava and maize varied between fields. Positive responses tended to decline with increasing yields in the control treatment. The average value-to-cost ratio (VCR) of fertilizer use for the FM regime was 3.6 and higher than for the FC regime (VCR = 1.6), resulting from higher maize yields when FM than when FC was applied. Revenue generated by maize constituted 84–91% of the total revenue of the cropping system. The highest profits were achieved with the FM regime when both cassava and maize were grown at high density. However, fertilizer application was not always advisable as 34 % of farmers did not realize a profit. For higher yields and profitability, fertilizer recommendations should be targeted to responsive fields based on soil fertility knowledge.

木薯与玉米间作是尼日利亚南部小农的常见做法。它提供粮食安全和早期获得玉米成分的收入。然而，这两种作物的产量在农田中普遍较低。2016 年和 2017 年在尼日利亚南部进行了多地点试验，以研究通过增加木薯和玉米植株密度和施肥来提高生产力和盈利能力的选择。2016 年和 2017 年分别在 126 个农田上进行了 2 个季节的 4 个和 6 个处理的试验，采用了一套不同的设计，包括两个作物密度和三个施肥水平水平的组合。玉米作物在低密度 (LM) 下进行测试，种植面积为 20,000 公顷^-1与具有 40,000 株植物的高密度 (HM) ha ^{-1 相比}。对于木薯，低密度 (LC) 有 10,000 株植物 ha ^-1而高密度 (HC) 有 12,500 株植物 ha ^-1。施肥遵循有利于玉米作物（FM：90 kg N、20 kg P 和 37 kg K ha ^-1）或木薯作物（FC：75 kg N、20 kg P 和 90 kg K ha ^{-1）的制度})，旁边是不施肥的对照 (F0)。较高的玉米密度 (HM)使第一个周期的适销玉米芯产量增加了 14%（3700 玉米芯公顷^-1）和 8%（2100玉米芯公顷^-1) 在第二个周期中，相对于 LM 处理。跨两个裁剪周期，施肥15％（5000穗轴公顷增加产量穗轴^-1）和19％（6700穗轴公顷^-1）在FC和FM制度分别。由于木薯植株密度增加，木薯贮藏根产量增加了 16 % (4 Mg ha ^-1 )，由于施肥（即两种施肥方式）增加了 14 % (4 Mg ha ^-1 )，但仅在第一次种植周期。在第二个周期中，增加的玉米植株密度 (HM) 使木薯贮藏根产量降低了 7%（1.5 Mg ha ^-1) 相对于 LM 处理。然而，高玉米密度对储藏根产量的负面影响被施肥抵消了。新鲜储藏根产量增加了 8% (2 Mg ha ^-1) 与不施肥的对照相比，在两种施肥方案中。木薯和玉米对肥料的反应因田地而异。随着对照处理中产量的增加，阳性反应趋于下降。FM 施肥的平均价值成本比 (VCR) 为 3.6，高于 FC 施肥 (VCR = 1.6)，这是因为 FM 比施用 FC 时玉米产量更高。玉米产生的收入占种植系统总收入的 84-91%。当木薯和玉米都以高密度种植时，FM 制度的利润最高。然而，施肥并不总是可取的，因为 34% 的农民没有实现利润。为了获得更高的收益和盈利能力，