1. Asadu, C. L. A., & Igboka, C. R. (2014). Effects of animal faeces and their extracts on maize yield in an ultisol of eastern Nigeria. Journal of Agriculture and Sustainability, 5(1), 1-13
2. Nutrient use efficiency in plants;Baligar;Communications in Soil Science and Plant Analysis 32(7-8),2001
3. Baloch, P. A., Riaz, U., Nizamani, F. K., Solangi, A. H., & Siddiqui, A. A. (2014). Effect of nitrogen, phosphorus and potassium fertilizers on growth and yield characteristics of radish (Raphinus sativus L.). American-Eurasian Journal of Agricultural & Environmental Sciences, 14(6), 565-569.
4. Bojović, B., & Marković, A. (2009). Correlation between nitrogen and chlorophyll content in wheat (Triticum aestivum L.). Kragujevac Journal of Science, 31(5827), 69-74.
5. El-Kazzaz, K. A., & El-Kazzaz, A. A. (2017). Soilless agriculture a new and advanced method for agriculture development: an introduction. Agricultural Research & Technology Open Access 3(2), 555610