Impact Assessment and Recommendation of Alternative Conjunctive Water Use Strategies for Salt Affected Agricultural Lands through a Field Scale Decision Support System – A Case Study

Abstract

Conjunctive use of saline/non-saline irrigation waters is generally aimed at minimizing yield losses and enhancing flexibility of cropping, without much alteration in farming operations. Recommendation of location-specific suitable conjunctive water use plans requires assessment of their long-term impacts on soil salinization/sodification and crop yield reductions. This is conventionally achieved through long-term field experiments. However such impact evaluations are site specific, expensive and time consuming. Appropriate decision support systems (DSS) can be time-efficient and cost-effective means for such long-term impact evaluations. This study demonstrates the application of one such (indigenously developed) DSS for recommending best conjunctive water use plans for a, rice-wheat growing, salt affected farmer's field in Gurgaon district of Haryana (India). Before application, the DSS was extensively validated on several farmers and controlled experimental fields in Gurgaon and Karnal districts of Haryana (India). Validation of DSS showed its potential to give realistic estimates of root zone soil salinity (with R = 0.76-0.94; AMRE = 0.03-0.06; RMSPD = 0.51-0.90); sodicity (with R = 0.99; AMRE = 0.02; RMSPD = 0.84) and relative crop yield reductions (AMRE = 0.24), under existing (local) resource management practices. Long term (10 years) root zone salt build ups and associated rice/wheat crop yield reductions, in a salt affected farmer's field, under varied conjunctive water use scenarios were evaluated with the validated DSS. It was observed that long-term applications of canal (CW) and tube well (TW) waters in a cycle and in 1:1 mixed mode, during Kharif season, predicted higher average root zone salt reductions (2-9%) and lower rice crop yield reductions (4-5%) than the existing practice of 3-CW, 3-TW, 3-CW. Besides this, long-term application of 75% CW mixed with 25% TW, during Rabi season, predicted about 17% lower average root-zone salt reductions than the cyclic applications of (1-CW, 1-TW, 2-CW) and (2-CW, 1-TW, 1-CW, i.e., existing irrigation strategy). However, average wheat crop yield reductions (16-17%) simulated under all these strategies were almost at par. In general, cyclic-conjunctive water use strategies emerged as better options than the blending modes. These results were in complete confirmation with actual long-term conjunctive water use experiments on similar soils. It was thus observed that such pre-validated tools could be efficient means for designing, local resource and target crop yield-specific, appropriate conjunctive water use plans for irrigated agricultural lands.

Cyclic use of saline and non-saline water to increase water use efficiency and soil sustainability on drip irrigated maize in a semi-arid region

“…Conjunctive use of saline and fresh water for irrigation allows the utilization of poor quality surface water and/or groundwater resources with freshwater (Rhoades, 1987;Sharma & Rao, 1998;Crescimanno et al, 2002;Datta & Jong, 2002;Yadav et al, 2004;Kaur et al, 2007). Blending and cyclic use are two options adopted when coordinating the use of water with different qualities (Rhoades et al, 1992;Wichelns et al, 2002;Hamilton et al, 2007;Dudley et al, 2008;Kulkarni, 2011).…”

A Review of Soil-Improving Cropping Systems for Soil Salinization

“…A Gypsum [143,144] A + M Gypsum in combination with various straw types [147] C Combinations of compost, anthracite coal powder, and water treatment residuals [145]; sewage sludge, epicarp-mesocarp of almonds [148]; combined application of manure and humic acid [149] C + A Combined application of gypsum, manure, and humic acid [149]; combination of compost, anthracite coal powder, water treatment residuals, and FeSO 4 .7H 2 O [145] D Improved drainage (modeled) [55]; Subsurface drainage [150,151]; Different types of subsurface drainage systems [152] Fe Application of Potash fertilizers [77] Fl Horizontal surface flushing [153] I Conjunctive use of saline/no saline irrigation [154]; Different types of deficit irrigation [85,87,155]; Alternate furrows and bed and furrow [56]; M Residue layer [55]; Palm leaves or plastic [156]; Straw mulching at different rates [32]; Polyethylene, pine bark or jute fibers [155]; Winter wheat straw [157] M + I + D Residue layer, improved drainage and optimized irrigation [55] P Forage cultivation [143,158]; Various crops during the fallow period [159]; Tomato in consociation with halophytes [160]; Phytodesalinized soil [139] R Conversion to continuous vegetable cropping [109]; Various crops during the fallow period [48,161] T Zero tillage [162]; Intermediate tillage or permanent bed planting [163]; Minimum tillage [32]; Direct drilling…”

Risk of Low Productivity is Dependent on Farm Characteristics: How to Turn Poor Performance into an Advantage

“…With ever expanding farm sizes, achieving joint multifaceted targets call for precision agriculture [13], but also many other types of decision support systems and tools [14][15][16]. Land use optimization is a means of allocating land in a rational way to improve resource use efficiency and to link the reduction of the environmental footprint to economic and social sustainability.…”