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Soil compaction under repetitive tillage and surface flood method of irrigation (SFMI) are significant hurdles for sustaining crop production in India, necessitating the adoption of efficient soil and water management strategies. Hence, a 3-year field study was conducted at two diverse agro-climatic locations (Abohar and Faridkot) to investigate the impact of subsurface drip (SUSD) fertigation on crop and water productivity of cotton-wheat cropping system (CWCS), over traditional practice (TP) (conventional tillage with SFMI and manual application of nutrients). The experiment was conducted in a factorial randomized complete block design with three levels of subsurface drip irrigation (SUSDI) [100, 80, and 60% of crop evapotranspiration (ETc)] and two fertigation levels [75% recommended dose of nutrients (RDN) and 100% RDN], where TP and surface drip (SD) fertigation at 80% ETc coupled with 100% RDN (Control 2), served as two control treatments. Cotton was raised through reduced tillage, while zero till drill was used for sowing wheat. The results revealed that, barring SUSDI at 60% ETc, both crops exhibited improved yield under all drip combinations of reduced or zero tillage over TP. Better mass and higher length of cotton roots in drip fertigation were evident due to improved steady-state infiltration rates (SSIR) and reduced bulk density (BD) under conservation tillage. When 100% RDN was applied, the 100% and 80% ETc SUSDI resulted in 26.7% and 24.7% higher seed cotton yield (SCY) than TP. Similarly, wheat yield with 100% RDN was improved by 10.5% and 14.4% under SUSDI of 80% and 100% ETc, respectively, over the TP. The results indicated that SUSD can be clubbed with reduced tillage for better soil health, improved crop yield, and higher apparent water productivity. The improved benefit to cost (B:C) owing to enhanced monetary returns over TP also substantiated that reduced tillage with SUSD is a viable and remunerative practice for CWCS. The study elucidated that reduced tillage exercised a beneficial effect on physical soil properties by lowering BD and improving SSIR. At the same time, SUSD could save huge amounts of irrigation water besides enhanced input use efficiency leading to higher crop productivity.

Sugarcane is one of the most suitable alternative crops to predominant rice–wheat cropping system in indo-Gangetic plains of India. However, grand growth period of this crop coincides with hot and dry summer months having higher evaporative demands which raise the crop water requirement during this period, thus narrowing its scope of being an alternative to rice–wheat cropping system. To enhance water productivity of sugarcane field, experiments were conducted at Punjab Agricultural University, Regional Research Stations, Faridkot and Kapurthala during spring 2016, 2017 and 2018 on planting methods and irrigation scheduling. Four planting methods comprised of P1: conventional flat (75 cm apart) with mulching @ 6 ha−1, P2: conventional flat without mulch, P3: paired row trench planting (30:120 cm) with mulch and P4: paired row trench planting without mulch as main plots and three irrigation schedules, i.e., irrigation at 0.60, 0.80 and 1.00 IW/CPE as subplots factors in split plot design. The results revealed that paired row trench planting (30:120 cm) with mulch @ 6 t ha−1 resulted into 162% and 123% higher apparent water productivity than conventional flat planted crop without mulch at Faridkot and Kapurthala, respectively. In paired row trench planting, irrigation water application was 58.4% and 52.0% lesser than conventional flat planted crop at Faridkot and Kapurthala, respectively, as water was applied only in trenches which actually curtailed the wettable area to 40%. Mulching in conventional flat planted crop improved the cane yield by 10.3% over non-mulch flat planted crop at Kapurthala, but this difference was only 6.1% in paired row trench planted crop at Faridkot. At Kapurthala, mulching in paired row trench planted crop enhanced the cane yield by 8.8%, but in conventional flat planted crop, this increase was up to 6.9%. On the basis of these results, it can be concluded that the planting sugarcane in paired row trench planting system with mulch @ 6 t ha−1 is the most viable planting system in sugarcane to attain higher crop and water productivity. Based on the availability of irrigation water, crop can either be irrigated at 0.6 or 0.8 IW/CPE for higher total and apparent water productivity and higher water-use efficiency. Higher benefit/cost ratio (mean over locations) is obtained under paired row trench planting with mulch and irrigation scheduling at 0.8 IW/CPE. [ABSTRACT FROM AUTHOR]

A field experiment was conducted to find out water and energy efficient irrigation and fertigation schedule for higher profitability from spring sunflower during 2014 and 2015. The experiment was laid out in randomized complete block design keeping combinations of three drip irrigation {(100, 80 and 60% of crop evapotranspiration (ETc)} and three fertigation schedules {(100, 80 and 60% of recommended dose of fertilizers (RDF) i.e. 60 kg N and 30 kg P 2 O 5 ha −1 )} with an extra absolute control treatment (furrow irrigation and manual application of RDF). The seed yield of sunflower was statistically at par between drip irrigation at 100 and 80% ETc but significantly better than 60% of ETc. However, apparent water productivity (AWP) and energy productivity was higher in drip at 80% ETc than 100 or 60% ETc. The crop drip irrigated at 80% ETc produced 397 g more seed yield with each cubic metre of irrigation water applied at yield advance and water saving of 27.8 and 33.3% than absolute control, respectively. Among the fertigation schedules, seed yield, oil yield and AWP were significantly higher from 100% RDF than 80 or 60% RDF and similar trend was observed for net returns and energetics. Drip irrigation either at 100% of ETc or 80% ETc with 100% of RDF or 80% of RDF produced significantly higher seed yield, net returns and energy productivity than absolute control. Thus, drip irrigation at 80% of ETc with 80% of RDF is more economically viable with higher water and energy productivity than absolute control. [ABSTRACT FROM AUTHOR]

The growth in the number of studies applying and expanding the concepts of the water footprint and virtual water trade in Spain has generated a wealth of lessons and reflections about the scarcity, allocation, productive use, and management of water from the viewpoint of a semi-arid country. This paper reviews the evolution of this research field in Spain since its introduction in 2005 and reflects on its main contributions and issues of debate. It shows how these concepts can be useful tools for integrated water accounting and raising awareness, when used with certain precautions: (1) Supply-chain thinking, taking into account value chains and the implications of trade, generally ignored in water management, can help to address water scarcity issues and sustainable water use. (2) Green water accounting incorporates land use and soil management, which greatly influences hydrological functioning. (3) The grey water footprint indicator analyzes pollution from an ecosystem point of view and facilitates the understanding of the water quantity and quality relationship. (4) Apparent water productivity analysis, innovatively incorporated into Spanish studies, considers the economic and social aspects associated with water use. However, the decision-making context should be broader, contextualizing and complementing water information with other indicators. [ABSTRACT FROM AUTHOR]