Agronomic performance of common bean in straw mulch systems and topdressing nitrogen rates in no-tillage

ABSTRACTIn no-tillage systems, straw coverage on soil surface is the key to success, and the choice of crops for rotation is crucial to achieve the sustainability and quality that conservation agriculture requires. The objective of this study was to evaluate the agronomic performance of the common bean cultivar IAC Formoso sown in succession to three straw mulch systems (corn alone, corn/Urochloa ruziziensisintercrop and U. ruziziensisalone) and topdress nitrogen rates (0; 40; 80; 120 and 160 kg ha-1N), at the four-leaf stage, three years after the implementation of no-tillage. The experiment was arranged in a randomized block split plot design, with three replications. Common bean highest yields were achieved in succession to U. ruziziensisalone and intercropped with corn. The corn/U. ruziziensisintercrop provided both straw and seed production, allowing for quality no-tillage. Topdressed nitrogen influenced the common bean yield when in succession to corn alone, U. ruziziensisalone and corn/U. ruziziensisintercrop in no-tillage.摘要：在免耕耕作系统中，土壤表面的秸秆覆盖是耕作成功的核心要素，而轮作作物的选择则是实现保护性农业所需可持续性与品质的关键环节。本研究旨在评估免耕系统实施三年后，于普通菜豆四叶期追施不同梯度氮肥（0、40、80、120及160 kg·ha⁻¹N）时，普通菜豆品种IAC Formoso在三种秸秆覆盖前茬模式（单作玉米、玉米/臂形草（Urochloa ruziziensis）间作、单作臂形草）下的农艺表现。本试验采用随机区组裂区设计，设置3次重复。结果显示，以单作臂形草及玉米与臂形草间作为前茬的处理，普通菜豆可获得最高产量；玉米/臂形草间作模式可同时兼顾秸秆还田与籽粒生产，保障优质免耕耕作的实施。在免耕体系下，追施氮肥对以单作玉米、单作臂形草及玉米/臂形草间作为前茬的普通菜豆产量均具有显著影响。