Dr Sohela Akhter1, Dr Md Khairul Alam1, Dr Rokeya Khatun1, Dr Nazmus Salahin1, Professor Richard W Bell2
1Bangladesh Agricultural Research Institute, Gazipur, Bangladesh, 2Murdoch University, Perth, Australia
Simultaneous increase in crop yield and improvement of soil health are key challenges of cropping intensification under rice–based cropping systems. A long-term experiment was commenced in 2007 at Gazipur, Bangladesh to determine nutrient management strategies that sustain soil fertility, increase cropping system productivity and overcome agronomic and soil constraints for successful crop production in rice-based triple cropping system on a Grey Terrace soil. Combinations of organic amendments (cowdung(CD) and poultry manure PM)) with chemical fertilizers were contrasted with native soil nutrients and with only inorganic nutrients to evaluate the changes in soil properties and yield of component crops over the years. Treatments were native fertility(control), chemical fertilizers with 5 tonne ha-1 CD to obtain medium yield goal(MYG*), only chemical fertilizer to obtain high yield goal (HYG*), chemical fertilizer with 5 tonne ha-1 CD to obtain HYG, chemical fertilizer with 3 tonne ha-1 PM to obtain HYG and chemical fertilizers to obtain MYG. Only mungbean residues were incorporated. Poultry manure applied at the rate of 3 t ha-1 together with the IPNS dose consistently produced the highest yield of all component crops of the maize-mungbean-rice cropping system (e.g. maize grain yield was 11.2 t ha-1 in 2017-2018, mungbean grain 1.1 t ha-1 and rice 5.1 t ha-1 in 2017). After 11 years of cropping under organic amended nutrient application, the soil organic matter (SOM) stocks (0-15 cm) increased by 6.3 tonnes ha-1 compared to initial SOM stock, while the control soil and the soils treated with only chemical fertilizers had decreased SOM (by 1.6 and 1.1 tonne ha-1, respectively). Most of the chemical properties of post-harvest soil were improved due to incorporation of organic manures through IPNS. The highest yield of crops and improved soil properties was associated with increased soil organic matter content in soils under the treatment.
* IPNS means amount of nutrients estimated to mineralize from cowdung and poultry manure were subtracted from STB chemical fertilizers.
*HYG and MYG were determined according to Fertilizer Recommendation Guide, BARC Bangladesh-2012 version
Dr Sohela Akhter has immeasurable experiences (35 years) in land management research. Her works deal with soil health improvement by increasing soil organic matter and nutrient status through integrated nutrient plant nutrition approach and integrated nutrient management system in rice based cropping systems. She also conducted research on problem soils in Bangladesh, mitigation of greenhouse gas emissions from soil and climate smart agriculture.