Maize (Zea mays L.) intercropping with forage plants has been adopted with the main goal of promoting benefits on soil physical properties. However, a better understanding of soil chemical attributes and crops nutrition under this system is necessary. The objective was to verify whether intercropping maize with Urochloa ruziziensis (Germ. & Evrard) Crins, a tropical forage grass originating in Africa, associated with N rates, could provide modifications on soil chemical attributes and nutritional status of maize and soybean [Glycine max (L.) Merr.] grown in succession. The experiment was carried out for three agricultural years at field conditions in a Rhodic Hapludox soil under no-till system in the state of Paraná, Brazil. Fall/winter (March–August) maize cropping systems, sole or intercropped with U. ruziziensis, were associated with four nitrogen (N) rates (0, 40, 80, and 120 kg ha^–1 N) applied as ammonium nitrate (30% N). The soil chemical attributes were not influenced by the factors studied. The N rates linearly increased phosphorus (P), sulfur (S), and copper (Cu) concentrations in maize leaves by 29, 30, and 49%, respectively, whereas for soybeans, only the concentration of manganese was raised by 15%. Maize leaf calcium was linearly reduced with N rates only when sole cropped, up to 15%. The cropping systems did not influence nutrient concentrations in soybean leaves; however, maize leaf concentrations of P within 80 and 120 kg ha^–1 of N, as well as potassium, S, and Cu at all N rates, were reduced in 9, 6.5, 6.5, and 8%, respectively.

中文翻译：

---

氮肥下大豆和玉米与紫草间作的土壤化学属性和营养状况

玉米（Zea mays L.）与饲料植物间作已被采用，主要目标是提高土壤物理特性的效益。然而，有必要更好地了解该系统下的土壤化学属性和作物营养。目的是验证将玉米与原产于非洲的热带牧草Urochloa ruziziensis (Germ. & Evrard) Crins 与 N 比率相关联，是否可以改变玉米和大豆的土壤化学属性和营养状况 [ Glycine max (L.) Merr.] 接连成长。该试验在巴西巴拉那州免耕制度下，在田间条件下进行了三年的农业试验。秋季/冬季（3 月至 8 月）玉米种植系统，单独或与U. ruziziensis间作，与四种氮 (N) 比率（0、40、80和 120 kg ha ^{–1）相关}N) 作为硝酸铵 (30% N) 应用。土壤化学属性不受所研究因素的影响。N 率使玉米叶片中的磷 (P)、硫 (S) 和铜 (Cu) 浓度分别线性增加 29%、30% 和 49%，而对于大豆，只有锰的浓度增加了 15%。仅当单独种植时，玉米叶钙随施氮量线性降低，最高可达 15%。种植系统不影响大豆叶片中的养分浓度；然而，在 80 和 120 kg ha ^–1的 N范围内，玉米叶片的 P 浓度以及所有 N 比率下的钾、S 和 Cu 分别降低了 9%、6.5、6.5 和 8%。