1. Abass MK, Jan N, Sultana Q, Ahmad SR, Rehman A (2006) Effect of different organic materials and chemical fertilizers on the yield of wheat and physical properties of soil. Sarhad J Agric 22(3):437–441
2. Akbar H, Ullah M, Jan MT, Jan A, Ihsanullah (2002) ield potential of sweet corn as influenced by different levels of nitrogen and plant population. Asian J Plant Sci 1(6):631–633
3. Arif M, Malik MA (2009) Economic feasibility of proposed cropping patterns under different moisture regimes of Pothwar plateau. Int J Agric Biol 11:27–32
4. Asai H, Samson BK, Stephan HM, Songyikhangsuthor K, Hommaa K, Kiyono Y, Inoue Y, Shiraiwa T, Horie T (2009) Biochar amendment techniques for upland rice production in Northern Laos. Field Crops Res 111:81–84
5. Aslam M, Mehmood G (2003) Economic feasibility of crop rotations under different rainfall zones. J Agric 35:27–23