Proper management of N, P, and K fertilizers is considered very important to maximize tuber yield and attain desirable processing quality. Generally, farmers apply NPK fertilizer rates based on the preplant soil tests. However, very limited information is available on the influence of available soil nutrients and in-season NPK application rates on yield and quality of tubers. In the present study, paired soil and tuber samples were evaluated from 170 commercial production sites to evaluate potential relationship between soil nutrients, tuber yield, and tuber quality. These paired samples gave us the opportunity to not only study yield response to fertilizer application rates but also study the relationship between soil nutrient availability and tuber nutrient concentrations. We found that about 50%, 80%, and 70% of farmers applied more NPK than recommended rates, respectively. Our results suggest that, in general available soil NPK increases tuber NPK concentrations and tuber N and K concentrations can reduce specific gravity. Interestingly, tuber P concentration had no effect on specific gravity. We also found some variations in these responses to nutrients (NPK) among cultivars suggesting some genetic control for the traits studied. Results also suggest that application of NPK fertilizers in excess of recommended rates on soils that are already rich in these nutrients does not increase tuber yields and may in fact increase potential environmental degradation associated with excessive fertilization and the cost of production.

中文翻译：

---

可用土壤养分和氮磷钾肥施用量对日本主季种植马铃薯的产量，品质和养分组成的影响

正确管理氮，磷和钾肥被认为对最大化块茎产量和达到理想的加工质量非常重要。通常，农民根据种植前的土壤测试来施用氮磷钾肥料。但是，关于可用土壤养分和季节氮磷钾施用量对块茎产量和品质的影响的信息非常有限。在本研究中，从170个商业生产地点评估了成对的土壤和块茎样品，以评估土壤养分，块茎产量和块茎质量之间的潜在关系。这些配对的样品使我们不仅有机会研究肥料用量对产量的反应，而且还研究了土壤养分利用率与块茎养分浓度之间的关系。我们发现大约50％，80％，分别有70％和70％的农民施用了高于建议比例的氮磷钾。我们的结果表明，通常可利用的土壤NPK会增加块茎NPK的浓度，块茎N和K的浓度会降低比重。有趣的是，块茎磷的浓度对比重没有影响。我们还发现不同品种对养分（NPK）的反应不同，这表明对所研究性状的某些遗传控制。结果还表明，在已经富含这些养分的土壤上施用超过建议用量的NPK肥料不会增加块茎产量，实际上可能会增加与过度施肥和生产成本相关的潜在环境退化。一般而言，土壤有效氮磷钾会增加块茎氮磷钾的浓度，块茎氮和钾的浓度会降低比重。有趣的是，块茎磷的浓度对比重没有影响。我们还发现不同品种对养分（NPK）的反应不同，这表明对所研究性状的某些遗传控制。结果还表明，在已经富含这些养分的土壤上施用超过建议用量的NPK肥料不会增加块茎产量，实际上可能会增加与过度施肥和生产成本相关的潜在环境退化。一般而言，土壤有效氮磷钾会增加块茎氮磷钾的浓度，块茎氮和钾的浓度会降低比重。有趣的是，块茎磷的浓度对比重没有影响。我们还发现不同品种对养分（NPK）的反应不同，这表明对所研究性状的某些遗传控制。结果还表明，在已经富含这些养分的土壤上施用超过建议用量的NPK肥料不会增加块茎产量，实际上可能会增加与过度施肥和生产成本相关的潜在环境退化。我们还发现不同品种对养分（NPK）的反应不同，这表明对所研究性状的某些遗传控制。结果还表明，在已经富含这些养分的土壤上施用超过建议用量的NPK肥料不会增加块茎产量，实际上可能会增加与过度施肥和生产成本相关的潜在环境退化。我们还发现不同品种对养分（NPK）的反应不同，这表明对所研究性状的某些遗传控制。结果还表明，在已经富含这些养分的土壤上施用超过建议用量的NPK肥料不会增加块茎产量，实际上可能会增加与过度施肥和生产成本相关的潜在环境退化。