Maize grain yields and profitability are enhanced in temperate growing areas as a result of an early sowing. However, cool conditions may constrain the uptake of nitrogen (N) and phosphorus (P) by the root system during the early and more susceptible growth stages. The application of starter fertilizers near the plant roots could ensure better N and P availability and improve early vigor of the crop. The aim of this study has been to quantify the overall benefits of a localized starter fertilization with N or P, or their combination, on maize (early development, grain yield, grain quality and sanitary traits). A 4-year field experiment was conducted in NW Italy during the 2014–17 growing seasons. The trial compared the sub-surface placement of N, P and NP in bands close to the maize seed furrows, as a starter fertilization strategy, with unfertilized controls on sandy silt loam (SSL), silt loam (SL) and silty clay loam (SCL) soils. These soils were placed side by side, and were characterized by low, high and medium N and plant-available P contents, respectively. The results showed that when N and P were applied together, the early vigor (plant height) and canopy development (NDVI values) of the maize were significantly enhanced, compared to both the controls and to the application of the single elements in all the soils. The positive growth responses to starter NP fertilization were combined with accelerated crop phenological development, so that anthesis occurred 2.4–3.1 days earlier. Thus, the grain yield was enhanced following the NP sub-surface placement (+7%, +15% and +11%, in SSL, SL and SCL, respectively), mainly due to an increase in the number of kernels per ear (+10%), while the grain moisture content was reduced, compared to the controls, in all the soils (−2.2%). The application of N or P alone did not consistently affect either the grain yield or the moisture content in any of the three soils. The starter fertilization strategy also affected both the qualitative and sanitary grain traits. NP and N both resulted in an increase in the grain hardness in the SL and SCL soils, but when P was applied alone, no significant effects were observed. The use of NP starter fertilization significantly reduced the ear injuries caused by European Corn Borer in all three soils (−44%), and reduced ear rot severity in the SSL and SL soils and the fumonisin content (−72%) in the SL and SCL soils, compared to the untreated controls. The synergistic effect of N and P applied as a sub-surface band at sowing had a consistent positive effect on the advancement of the flowering dates at different sites in different years, even in soils that have tested high to P or N. Thus, the application of NP starter fertilizer is a crop practice that should be considered in North Italy and for similar soils and environments.

由于提前播种，温带种植区的玉米产量和盈利能力得到提高。然而，凉爽的条件可能会在早期和更敏感的生长阶段限制根系对氮 (N) 和磷 (P) 的吸收。在植物根部附近施用起始肥料可以确保更好的N和P利用率并提高作物的早期活力。本研究的目的是量化使用 N 或 P 或其组合进行局部发酵剂施肥对玉米的总体益处（早期发育、谷物产量、谷物质量和卫生性状）。在 2014-17 生长季节期间，在意大利西北部进行了为期 4 年的田间试验。该试验比较了 N、P 和 NP 在靠近玉米种子沟的条带中的地下放置，作为起始施肥策略，对沙质粉砂壤土 (SSL)、粉砂壤土 (SL) 和粉质粘壤土 (SCL) 土壤进行未施肥控制。这些土壤并排放置，并分别以低、高和中等 N 和植物有效磷含量为特征。结果表明，与对照和在所有土壤中施用单一元素相比，当N和P一起施用时，玉米的早期活力（株高）和冠层发育（NDVI值）显着增强。 . 对起始 NP 施肥的积极生长反应与加速作物物候发育相结合，因此开花提前 2.4-3.1 天。因此，在 NP 次表面放置后，晶粒产量提高了（在 SSL、SL 和 SCL 中分别为 +7%、+15% 和 +11%），主要是由于每穗的籽粒数量增加（+10%），而与对照相比，所有土壤中的谷物水分含量降低（-2.2%）。单独施用 N 或 P 不会持续影响三种土壤中任何一种的谷物产量或水分含量。发酵剂施肥策略也影响了谷物的质量和卫生性状。NP 和 N 都导致 SL 和 SCL 土壤的颗粒硬度增加，但当单独施用 P 时，没有观察到显着影响。使用 NP 施肥显着降低了欧洲玉米螟在所有三种土壤中造成的耳部损伤（-44%），并降低了 SSL 和 SL 土壤中的穗腐病严重程度以及 SL 和 SL 中的伏马菌素含量（-72%）。与未经处理的对照相比，SCL 土壤。