Nitrogen in plant-soil system after lime and gypsum application in production system

Author(s)

Murilo de Souza

• Document type: Doctoral Thesis
• Press: Botucatu. 2022-04-06.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agronômicas. Botucatu
• Defense date: 2022-02-02
• Advisor: Ciro Antonio Rosolem

Abstract

Maize has been cultivated as a relay crop in the no tillage system (NTS), after soybean, but there is still no accurate information about its response to nitrogen (N) in this cultivation system, especially when intercropped with forage grasses, as well as about the consequences on the next soybean crop, and carbon (C) cycle processes in the soil. The objective of this work was to evaluate the fertilizer N use efficiency (NUE) by maize as a relay crop intercropped with Guinea grass (Megathyrsus maximus), root growth of crops in NTS, crop yield and carbon use efficiency (CUE) as a function of soil acidity alleviation using lime and gypsum. An experiment was carried out with soybean crop and subsequent to soybean, maize was cultivated intercropped with Guinea grass, in the 2017, 2018 and 2019 seasons. The treatments consisted of the application of lime, lime + gypsum and control (without amendments application) in the soybean crop, and four N doses (0, 80, 160 and 240 kg ha-1 ) applied to maize. In the treatment with 160 kg N ha-1 , ammonium sulfate enriched with 15N was applied, to evaluate the N-fertilizer recovery. The amendments application was efficient in promoting greater root growth, being more evident with the lime associated with gypsum application. Acidity soil correction also promoted greater N uptake by maize plants intercropped with Guinea grass, consequently, resulted in greater fertilizer NUE. Furthermore, there is evidence that the addition of N and phosphorus (P) can increase the use efficiency of the added carbon in acid-corrected soils, suggesting that the soil microbial community is limited by mineral nutrient restrictions. (AU)

• FAPESP's process: 17/22134-0 - Nitrogen in soil-plant system as affected by lime and gypsum management under no till
• Grantee: Murilo de Souza
• Support Opportunities: Scholarships in Brazil - Doctorate