Silage maize (Zea mays L.) is an important crop for forage on Northwestern European dairy cattle farms. We examined the effect of readily available soil phosphorus (P) on early maize growth and linked in-season height growth to final harvest yield using field plots with contrasting P supply in a one-year study embedded in a long-term experiment. Water-extractable P (Pw) was used as a proxy for readily available P in soil. Plant height, dry matter (DM) accumulation, P and nitrogen (N) uptakes were determined eight times from the two-leaf stage until final whole-crop harvest and fitted to logistic growth models. The models revealed that the final yield was significantly related to the time required to reach the maximum rate of height growth (occurring from 330 to 485 accumulated growing degree units, GDU), but not the time required to reach the maximum rate of DM accumulation (occurring from 561 to 649 GDU). Furthermore, plant height at the four-leaf stage and onwards was significantly related to the final harvest yield. Soil Pw linked closely to height growth parameters; higher levels of Pw gave earlier peaks in height growth. For this light sandy loam with a wide gradient in P content, we conclude that suboptimal P supply postpones height growth and reduces final yields. A sufficient P supply links to an early rapid increase in plant height and forms the potential for optimum nutrient uptake and high forage yields. Thus, early-season plant height may serve as a simple morphometric indicator for final yields.

中文翻译：

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早期株高：与磷供应对比的青贮玉米产量的决定性因素

青贮玉米（Zea maysL.) 是西北欧奶牛场的重要饲料作物。在一项嵌入长期实验的为期一年的研究中，我们检查了容易获得的土壤磷 (P) 对早期玉米生长的影响，并将季节高度增长与最终收获产量联系起来。可水萃取的 P (Pw) 被用作土壤中容易获得的 P 的代表。从两叶期到最终全作物收获，测定了 8 次植物高度、干物质 (DM) 积累、P 和氮 (N) 吸收，并拟合逻辑生长模型。模型显示，最终产量与达到最大高度生长速率（从 330 到 485 累积生长度单位，GDU）所需的时间显着相关，但不是达到最大 DM 积累率所需的时间（从 561 到 649 GDU）。此外，四叶期及以后的株高与最终收获产量显着相关。土壤 Pw 与高度生长参数密切相关；Pw 水平越高，身高增长的峰值就越早。对于这种 P 含量梯度较宽的轻质砂壤土，我们得出结论，次优的 P 供应会延缓高度生长并降低最终产量。充足的磷供应与植物高度的早期快速增加有关，并形成最佳养分吸收和高草料产量的潜力。因此，早季植物高度可以作为最终产量的简单形态指标。四叶期及以后的株高与最终收获产量显着相关。土壤 Pw 与高度生长参数密切相关；Pw 水平越高，身高增长的峰值就越早。对于这种 P 含量梯度较宽的轻质砂壤土，我们得出结论，次优的 P 供应会延缓高度生长并降低最终产量。充足的磷供应与植物高度的早期快速增加有关，并形成最佳养分吸收和高草料产量的潜力。因此，早季植物高度可以作为最终产量的简单形态指标。四叶期及以后的株高与最终收获产量显着相关。土壤 Pw 与高度生长参数密切相关；Pw 水平越高，身高增长的峰值就越早。对于这种 P 含量梯度较宽的轻质砂壤土，我们得出结论，次优的 P 供应会延缓高度生长并降低最终产量。充足的磷供应与植物高度的早期快速增加有关，并形成最佳养分吸收和高草料产量的潜力。因此，早季植物高度可以作为最终产量的简单形态指标。我们得出结论，次优的磷供应会推迟高度增长并降低最终产量。充足的磷供应与植物高度的早期快速增加有关，并形成最佳养分吸收和高草料产量的潜力。因此，早季植物高度可以作为最终产量的简单形态指标。我们得出结论，次优的磷供应会推迟高度增长并降低最终产量。充足的磷供应与植物高度的早期快速增加有关，并形成最佳养分吸收和高草料产量的潜力。因此，早季植物高度可以作为最终产量的简单形态指标。