Soil microbial biomass, organic C, and soybean physiology in integrated crop–livestock systems with different inputs

ABSTRACT

This study assessed the effect of soil inputs, i.e., lime, gypsum and fertilizers, on biological parameters, total organic C (TOC), and growth and physiology of soybean under integrated crop-livestock system (ICLS). Five soil inputs were evaluated: CT (no input), T1 (lime), T2 (lime and gypsum), T3 (lime, gypsum and NPK), and T4 (lime, gypsum, NPK and micronutrients). The highest TOC and soil microbial biomass values were found in T4 (7.8 g kg⁻¹) and T1 (146.7 mg C kg⁻¹), respectively. Soil respiration and dehydrogenase were higher in T2 (5.2 mg CO₂ kg⁻¹ and 0.19 mg kg⁻¹, respectively). The highest soybean biomass, shoot dry weight, and chlorophyll values were found in T2 (14.1 g plant⁻¹, 12.6 g plant⁻¹, and 12.9 chlorophyll index plant⁻¹, respectively), while total N and phenols were higher in T1 (27.4 mg N g⁻¹ and 34.1 µg mL⁻¹, respectively). The highest lipid peroxidation and peroxidase activity values were observed in CT (1.9 µM g⁻¹) and T1 (1.58 µM g⁻¹), respectively. The soil conditioning via the application of lime and gypsum can contribute to improving the status of biological parameters and TOC in ICLS, and it could contribute for improving the growth and physiology of soybean.

KEYWORDS:

• Agricultural systems
• limestone
• micronutrients
• plant growth

Disclosure statement

The authors declare that they have no conflict of interests.

Additional information

Funding

This study was supported by the Fundacao de Amparo a Pesquisa do Estado de São Paulo – FAPESP [grant 2017/16202-2]. Ademir Sergio Ferreira Araujo thanks CNPq-Brazil for his Fellowship of Research [grant 305069/2018-7];Fundação de Amparo à Pesquisa do Estado de São Paulo [grant 17/16202-2];