Assessment of environmental parameters in relation to different agro-water management practices in south-west coastal region of Bangladesh

Abstract

Salinization of productive agrieulturuJ. land~ in ~outhwcstern cou.srnl Fl;mgladcsh and their reclamation are getting distinct importan~e lo the local people as well a~ policy makers. Salinization hll~ heen cstablished as th~ prime causc of environmental d~gradati"n in the region ami there is an urgency to lind out a water mallag~menl practice which is economically b~nelieiaL socially acceptable llnd environmentally sustainable. Keeping thcse viewpoints, this ~llldy was undeltaken to e\aluate the present statuses 0 f di [fcrcnt agro-\\(aler manllgemenl practices in Dumuria Upazila, to carry out 1<Jboratory analyses of sele~kd soil and water qualit}, parameter;; of agriculll.lnll fields, llIld to ass~ss the environmcntal eons~qu~n~es of those farming practic~s. Four different types of agro-water management pra~tkes (AWMPs) with three gher~ under each practice were s~lected for investigation. Se\'eral important soil and v,ratcr quality parameter~ (tempcrature, salinity, pH, H:, 1 DS, DO, nco] -,ci+, Mg~+, CL N'a+, K', sol, NO,', etc.) during the pr~- and post-boro season of 2009- 10 Were analyzed to ealculat~ th~ mcan soil and waler quality changc indicators (MSQ1, MWQ1). nesid~s the~e, management parameters, such a.\ cropping pattern, iITigatlOn, water exchange, use of ferlili~er. u<;cof pesticide, numb~r of years of bom culti\ation, \,egetation Oil gher dyke~, etc., and economics of produdion were consid~red li,r evaluation of best practices among different AWMPs w.ing multicriteria anal}.,is (MCA). Thc highest del~rinrali()n of soil quality was found in Ihe Type-3 AWMP and the lowe't in th~ Typc-2 AWMP, In case ofwaler ljlmlity, the order of dcterior<ltion ,,'as found to bc: 1'ype-3 AWMP > Type-4 AWMP > Type-2 AWMP> Type-l AWMP. Thc dcgree of cOITelalion of economic paramelers with quality and management parameters wa, used In give weightage of parameter:<. in MCA - a strong relation (P < 0.01) was given a high weightage and a mO(krat~ relation (0.01 < P < 0.10) was gi\'en a low weighlagc. Thus the Type-2 AWMP got lh~ highest 100al average score and appear~d to b~ Ih~ hest AWMP. This ,vas due to th~ commLlnity management approach for conlrolling saline watcr into the ghers, use of more organic fertilizer, usc of IPM t~chniqu~~, le~s cropping intensity, less deterioration of soil and water lj\llllily, higher economic return, etc. So, IrolTI this study it can he said that th~ ~onmnllla[ approach in water management for I-lYV boro rice cultivation \\(ith!1 crop rotation of golda-bagda-\vhite fish i, the best AW!vlP among the current practices in the study area