Intercropping and cover crop effects on maize nitrogen requirement for optimal growth

Abstract

Intercropping maize (Zea mays L.) with cover crops (Crotalaria spectabilis and Urochloa ruziziensis) is a sustainable cultivation strategy that can generate ecological benefits combined with grain yield (GY). However, cover crops may require nitrogen (N) fertilization management to be adjusted to obtain a high GY in intercropping systems. This study was carried out over 2 years in southeastern Brazil using randomized complete block design in a split-plot scheme. The plots were composed of three cropping systems: sole maize, maize + U. ruziziensis and maize + C. spectabilis. The subplots consisted of four N levels: 0, 70, 140 and 210 kg/ha. The GY of the maize + U. ruziziensis may be reduced by 13% compared to the sole maize. The GY of the sole maize increased up to 11.3 Mg/ha for 95 kg/ha of N in the first year and 6.7 Mg/ha for 169 kg/ha of N in the second year. The GY of the maize + U. ruziziensis intercropping system showed linear increments of 120 kg/ha for every 10 kg/ha of N applied. In the maize + C. spectabilis intercropping, GY increased up to 9.8 Mg/ha for 201 kg/ha of N in the first year, without any variation during the second year. The land equivalent ratio (LER) of intercropping was increased by more than 35% compared to that of sole maize, and N fertilization increased the LER of the sole maize and maize + U. ruziziensis intercropping. Maize intercropping had higher LER values with greater demand for nitrogen to obtain similar yields compared to sole maize cropping.

Crop Succession and Nitrogen Splitting Fertilization in Common Bean in Newly Implemented No-tillage System

“…In the intercropping system, the competition exerted by U. ruziziensis against maize is veri ed by the reduction of 8.7% in GY when compared to the sole cultivation of the cereal in the rst year. In the second year, the intercropping system generated maize plants with lower MEH and SD, characteristics that, according to Souza et al (2022), are indicative of competition in maize intercropping systems. However, in the second year the intercropping with U. ruziziensis did not reduce the GY of maize.…”

“…However, in the second year the intercropping with U. ruziziensis did not reduce the GY of maize. The reduction in the GY of maize when it is intercropped depends on several factors, especially the species, sowing time, sowing modality and sowing density of the forage, as well as the spacing between maize rows and edaphoclimatic conditions (Borghi et al, 2013;Queiroz et al, 2016;Souza et al, 2022). However, the ecosystem bene ts promoted by the use of forage species as cover crops over the years are greater than the possible reduction of maize GY in some periods (Baptistella et al, 2020;Souza et al, 2022).…”

“…Although in the two years the common bean showed leaf N content within the su ciency range (30 to 50 g kg − 1 ) considered adequate (Wutke et al, 2022), the leaf N contents in the second year were lower when the crop was sown after maize intercropped with U. ruziziensis and sole U. ruziziensis. This response variable indicates greater immobilization of soil N in the systems with higher straw production, reducing the availability of this nutrient for the crop and, consequently, the leaf N content (Souza et al, 2022).…”

“…However, the great disadvantage of these species as sole crops is the lack of direct and rapid economic return for the producer. Thus, the intercropping of Urochloa with maize becomes an alternative to associate the ecosystem bene ts promoted by the forage with a cash crop (Borghi et al, 2013;Souza et al, 2022). Thus, the tripod of sustainability is formed, promoting economic, environmental and social bene ts to the production system.…”