Vol.:(0123456789) 1 3 Journal of Crop Science and Biotechnology https://doi.org/10.1007/s12892-020-00035-8 ORIGINAL RESEARCH Biochar in combination with compost reduced Pb uptake and enhanced the growth of maize in lead (Pb)‑contaminated soil exposed to drought stress Sifau Adenike Adejumo 1  · Dorcas Omotayo Arowo 1  · Mary Bosede Ogundiran 2  · Prashant Srivastava 3 Accepted: 1 April 2020 © Korean Society of Crop Science (KSCS) and Springer Nature B.V. 2020 Abstract Crops are constantly faced with the challenges of different abiotic stresses on the field. Development of sustainable approach for stress amelioration on crop is pertinent. This study investigated the ameliorative roles of biochar and compost on maize crop simultaneously subjected to drought and heavy metal (Pb) stresses. Metal stress was imposed by growing maize on Pb-contaminated soil while drought stress was imposed by reducing the soil field capacity to 25 and 50%. Four levels (0, 5, 10 and 15 t/ha) of biochar and compost replicated three times as well as their combinations were used. Pb uptake, transloca- tion factors, photosynthetic pigments, osmolytes (proline and cysteine), biomass accumulation in stressed maize crop, and post-cropping soil Pb concentration were determined. Combination of stresses reduced biomass accumulation in maize. Biochar in combination with compost, however, enhanced biomass production in stressed maize crop by 50–75% compared to unamended soil (control). Proline accumulation was more under the single stress of heavy metal (100% FC) compared to combined stresses. Unlike proline, combined stresses of Pb and 50% FC enhanced chlorophyll and cysteine accumulation more than single stress. Their concentrations were further increased with amendments compared to control. Pb accumulation in maize crop was more under combined stresses than single stress (100% FC). Compared to other soil amendments, applica- tion of biochar alone at 10 t/ha, generally reduced Pb uptake by maize and post-cropping soil Pb concentration. Biochar and compost reduced Pb uptake, and enhanced biomass and osmolyte production in stressed maize crop. Keywords Heavy metals · Oxidative stress · Osmolytes · Contamination · Organic amendments · Abiotic factors Introduction Maize is one of the most important staple food crops in Africa and ranks third after rice and wheat (Raji 2003). It serves as raw material for industries (Ayoola and Makinde 2007) and source of income to the farmers. Maize yield is, however, affected by a range of biotic and abiotic stress fac- tors. Abiotic stress factors, such as high salinity, low soil fertility, soil contamination with heavy metals and drought pose serious threats to crop production and food security. Among these, drought and soil contamination are the major abiotic factors that affect agricultural productivity (Jaleel et al. 2009). International Maize and Wheat Improvement Centre (CIMMYT) also attributed the poor yield of maize in the field to poor soil fertility and drought (Edmeades and Deutsch 1994). Though agricultural crops are generally faced with dif- ferent environmental challenges during their lifecycle land contamination with heavy metals and drought has more del- eterious effects on the crop growth and development (Aslam et al. 2006; Jaleel et al. 2009). Apart from reduction in crop yield which is common to both, heavy metals also have direct effects on consumer health through food chain as a result of accumulation in the food crop (Boussen et al. 2013). Lead (Pb) is most importantly considered as one of the most toxic elements to plants and animals (Ginneken et al. 2007; Padmavathiamma and Li 2010; Huang et al. 2012) due to * Sifau Adenike Adejumo nikade_05@yahoo.com 1 Department of Crop Protection and Environmental Biology, University of Ibadan, Ibadan, Nigeria 2 Department of Chemistry, University of Ibadan, Ibadan, Nigeria 3 Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), University of Newcastle, ATC Building, Callaghan, NSW 2308, Australia