Abstract
Bhuiyan, M.A.H. 2005. Evaluation of introducing mungbean into cereal based cropping pattern for sustainable soil fertility and productivity. Ph.D. Dissertation. Dept. of Soil Science, Bangladesh Agricultural University, Mymensingh.
A study has been carried out during 1999-2002 at the Bangladesh Agricultural University (BAU) farm to investigate the possibility of substituting a rice crop (a cereal) with mungbean (a pulse) for maintaining soil fertility and better economic return. One set of experiment was conducted with five mungbean varieties, with or without inoculation, of which Barimung-2 was found better in producing nodules, stover and seed yields, and accumulating more nitrogen. Apparent nutrient balance of two cropping patterns, wheat (Kanchan)-rice (BR26)-rice (BRRI Dhan32) and wheat (Kanchan)- mungbean (Barimung-2)-rice (BRRI Dhan32), has been compared under different nutrient management packages. In both cropping patterns, wheat received four nutrient treatments: absolute control (T1), soil test based nutrient doses (STB) for moderate yield goal (MYG) (T2), STB for high yield goal (HYG) (T3), and T2+ 5 t cowdung (CD) ha' (T4). In the following season, each of the wheat plots under four different treatments was divided into three sub-plots. Aus rice (BR26) was grown in one sub-plot of each of the four treatments as absolute control (T1), STB for MYG (T2.1), STB for HYG (T3.1) and T2.1 + residual of CD (T4.1). Mungbean was grown in other two sub-plots of each of the four treatments as absolute control (T2), STB for average yield goal (AYG) (T2.2), STB for AYG (T3.2) and T22+ residual of CD (T4.2). Except the T1.2, mungbean of all other treatments were inoculated with Bradyrhizobium. For the third crop i.e. T. Aman (BRRI Dhan32), each sub-plot became an individual treatment giving a total of 12 treatments. Three treatments on the T, plots were: absolute control (T1), absolute control + mungbean residues removed (MRR) (T1.2.1), absolute control + mungbean residues incorporated (MRI) (T1.22), three treatments on the T2 plots as STB for MYG (T21), STB for MYG + MRR (T2.2.1), and MRI + reduced doses of chemical fertilizers (RDCF) (T2.2.2) for MYG. Similarly, T3 plots received three treatments as STB for HYG (T3.1), STB for HYG + MRR (T3.2.1), STB for HYG + MRI + RDCF (T3.2.2) for HYG. The T, plots received 5 t CD ha1 and other treatments and splitting were similar to T2. Such a 3-crops cycle was repeated for three years. The highest mean yield (3.13 t ha'') of wheat was obtained in T3 plots. T. Aman gave the highest mean yield of 4.81 t ha' in the plots where mungbean residues were incorporated and reduced doses of chemical fertilizers were applied (T3.2.2). Nutrient uptake was strongly correlated with the yield of rice and wheat. The economic analysis revealed higher BCR for the wheat-mungbean-rice pattern although the net return in all treatments was higher for wheat-rice-rice pattern. The apparent nutrient balance for N (-15 to -37 kg ha ̈'yr') and K (-79 to -97 kg ha'yr') was good in case of wheat- mungbean-rice pattern compared to that of wheat-rice-rice pattern (N: -46 to -54 kg ha 'yr'; and K: -84 to -105 kg ha'yr') clearly indicating that incorporation of mungbean stover helped reducing the negative balances of nitrogen. Similarly, the apparent nutrient balance for P, K, S, Zn and B was also comparatively good for wheat-mungbean-rice pattern. Therefore, the wheat-mungbean-rice pattern may be recommended for the general practice, particularly for the typical wheat growing light soils of Bangladesh where yield of aus rice is low and improvement of soil health is inevitable, for sustainable productivity.