Patterns of change in soil organic matter, physical properties and crop productivity under tillage practices and cropping systems in Bangladesh

Abstract

SUMMARYConservation agriculture (CA) is inadequately developed for rice-based cropping systems widely practiced in Bangladesh. The current drawback is the implementation of CA for all crops including rice (Oryza sativa L., ecotype ‘transplanted aman’ [T. aman]) to increase rice–wheat (Triticum aestivum L.) rotation productivity. It is important to identify the best combination of tillage types and cropping systems to achieve a high yield of component crops and improve soil health. Three tillage practices, assigned to main experimental plots [namely, zero tillage (ZT), conventional tillage using a rotary tiller (CT) and deep tillage using a chisel plough (DT)] and three different cropping systems, assigned to sub-plots [namely, WFT: wheat–fallow–T. aman, WMT: wheat–mungbean (Vigna radiata L. Wilczek)–T. aman and WDT: wheat–dhaincha (Sesbania rostrata)–T. aman], were tested. After 4 years, ZT under WDT and WMT significantly increased soil organic matter (SOM) at 0–150 mm depth, and these replicates also held the highest levels of total organic carbon. Soil organic carbon (C) increased at a rate of 1.17 and 1.14 t/ha/y in ZT under WDT and WMT, respectively, while CT and DT under WFT were almost unchanged. After 4 years, SOM build-up by the three-crop system (WDT and WMT) under ZT helped conserve soil moisture and improve other soil properties, such as reduction in soil strength and bulk density and increase plant available water content, thus maintaining an optimum soil water infiltration rate. Zero tillage under WMT and WDT showed significant improvements in root mass density of rice and wheat at increased soil depth. The WDT and WMT plots under DT consistently gave the highest yield followed by WDT and WMT under CT, in contrast with ZT under WMT or WDT, which showed the highest improvement in crop yields over the years. In summary, minimum soil disturbance together with incorporation of a legume/green manure crop into the rice–wheat system as well as the retention of their residues increased soil C status, improved soil properties and maximized grain yields.

Effect of Tillage and Residue Retention on Soil Properties and Crop Yields in Wheat-Mungbean-Rice Crop Rotation under Subtropical Humid Climate

“…Yields of all crops showed increasing trend under minimum tillage practice in the second year of cropping system continuation [15].…”

Impact of Zero Tillage and Tillage Practice in Chickpea Production

“…Minimum or zero tillage practice to some extent increases SOM levels (Busari and Salako, 2013), enriches soil nutrients (Alam, 2018), water retention capacity (Aziz et al, 2013), and decreases the cost of production (Salahin, 2017) by reducing fuel use for intensive tillage and irrigation requirements (Johansen et al, 2012). Enormous studies conducted in home and abroad also showed that zero and minimum tillage increases SOM, microbial activity, total N, and extractable P, S, Zn and B at the soil surface to a large extent compared to conventional tillage (Alam et al, 2016;Vu et al, 2009).…”

Effects of tillage practices and nutrient management on crop productivity and profitability in Jute-T. aman rice- onion cropping system

“…In addition, puddling of soil accelerates decomposition of SOM, increases greenhouse gas emissions (GHGs)and nitrogen loss (Alam et al, 2019b) and inflicts increased costs for upland crop establishment (Bell et al, 2019).In contrary, minimum or zero tillage practice increases SOM levels (Busari and Salako, 2013),enriches nutrients in soils (Alam, 2018) and water retention capacity (Aziz et al, 2013), and decreases production costs (Salahin, 2017) and GHGs (Alam et al, 2019b) by reducing fuel use for intensive tillage and irrigation requirements (Johansen et al, 2012). There are many researches on zero and minimum tillage that has been proved as a greater technique to increase SOM, microbial activity, total N, and extractable P, S, Zn and B at the soil surface compared to conventional tillage (Alam et al, 2016a;Vu et al, 2009). Besides, non-puddled rice crop establishment has been recently developed and performed well in yield, soil health, economics and climate change mitigation (Bell et al, 2019;Salahin, 2017;Alam, 2018;Alam et al, 2019a).…”