Data from: High-yielding corn response to applied phosphorus, potassium, and sulfur in Nebraska

Nutrient management recommendations may change as yield levels and efficiency of crop production increase. Recommendations for P, K, and S were evaluated using results from 34 irrigated corn (Zea mays L.) trials conducted in diverse situations across Nebraska. The mean yield was 14.7 Mg ha−1 with adequate fertilizer applied. The median harvest index values were 0.52, 0.89, 0.15, and 0.56 for biomass, P, K, and S, respectively. Median grain yields were 372, 49, and 613 kg kg−1 of aboveground plant uptake of P, K, and S, respectively. The estimated critical Bray-1 P level for corn response to 20 kg P ha−1 was 20 mg kg−1 when the previous crop was corn compared with 10 mg kg−1 when corn followed soybean [Glycine max (L.) Merr.]. Soil test K was generally high with only three site-years <125 mg kg−1 Over all trials, application of 40 kg K ha−1 resulted in a 0.2 Mg ha−1 mean grain yield decrease. Application of 22 kg S ha−1 did not result in significant yield increase in any trial. Soil test results accounted for twice as much variation in nutrient uptake when soil organic matter (SOM) and pH were considered in addition to the soil test nutrient values. The results indicate a need to revise the current recommendation for P, to maintain the current K and S recommendations, and to use SOM and pH in addition to soil test nutrient values in estimating applied nutrient requirements for irrigated high yield corn production.

随着作物产量水平与生产效率的提升，养分管理推荐方案亦需随之调整。本研究以美国内布拉斯加州不同生境下开展的34个灌溉玉米（Zea mays L.）田间试验结果为依据，对磷（Phosphorus, P）、钾（Potassium, K）、硫（Sulfur, S）的养分管理推荐方案展开评估。在足量施肥条件下，试验的平均籽粒产量为14.7 Mg·ha⁻¹。针对生物量、磷、钾、硫的收获指数（Harvest Index）中位数分别为0.52、0.89、0.15和0.56。每千克地上部磷、钾、硫养分吸收量对应的籽粒产量中位数依次为372、49和613 kg·kg⁻¹。当后茬作物为玉米时，玉米对20 kg P·ha⁻¹施肥量的响应临界布雷一号有效磷（Bray-1 P）水平估算值为20 mg·kg⁻¹；而当后茬为大豆（Glycine max (L.) Merr.）时，该临界值仅为10 mg·kg⁻¹。土壤测试钾含量整体处于较高水平，仅3个试验点次的土壤测试钾含量低于125 mg·kg⁻¹。综合所有试验结果，施加40 kg K·ha⁻¹会使籽粒产量平均降低0.2 Mg·ha⁻¹。所有试验中，施加22 kg S·ha⁻¹均未使籽粒产量出现显著提升。若在土壤测试养分指标之外同时纳入土壤有机质（Soil Organic Matter, SOM）与pH值，土壤测试结果对养分吸收量变异的解释度可提升至原先的两倍。本研究结果表明，需修订当前的磷养分管理推荐方案，维持现有钾、硫养分推荐方案，并在估算灌溉高产玉米的养分施用量时，除土壤测试养分指标外，同步纳入土壤有机质与pH值作为参考依据。