Deficit Irrigation Scheduling and Superabsorbent Polymer‐ Hydrogel Enhance Seed Yield, Water Productivity and Economics of Indian Mustard Under Semi‐Arid Ecologies

Abstract

Oilseed brassicas are extensively grown in the water‐stressed ecologies of India. Sufficient irrigation, deficit irrigation scheduling (DIS) with limited irrigation water and rainfed (no irrigation) conditions were assessed with and without the use of superabsorbent polymer‐hydrogel (SAP‐hydrogel) under a micro‐sprinkler irrigation system (MIS) for Indian mustard. Irrigation scheduling at an irrigation water/cumulative pan evaporation ratio (IW/CPE) of 0.8, 0.6 and 0.4, along with use of SAP‐hydrogel, produced almost equal dry matter per plant (113, 115 and 109 g plant−1), which was, however, significantly higher (P ≤ 0.05) over rainfed (86 g plant−1). The seed yield under DIS (0.6 IW/CPE) increased by 39.3% over rainfed + hydrogel (HG). Also, the seed yield obtained under irrigation scheduling at a ratio of 0.4 IW/CPE was found to be similar to that obtained in rainfed + HG treatment. A similar water productivity (WP) of 10 kg ha−1 mm−1 was obtained with DIS at 0.4 IW/CPE + HG and at 0.8 IW/CPE‐HG; however, a higher total water productivity (WPt) was recorded under DIS at 0.6 and 0.4 IW/CPE + HG (23 and 29 kg ha−1 mm−1, respectively) over the same irrigation schedules excluding HG. The economics of HG application under DIS was better due to higher net returns, although the highest B : C ratio (1.92) was recorded in DIS (0.4 IW/CPE), trailed by irrigation scheduling at IW/CPE 0.8 and 0.6. Overall, it could be concluded that DIS through micro‐sprinkler and use of HG enhanced seed, oil, water productivity and energy dynamics under water‐constrained conditions in semi‐arid ecologies. © 2019 John Wiley & Sons, Ltd.

Mitigating moisture stress in Brassica juncea through deficit irrigation scheduling and hydrogel in ustocherpts soils of semi-arid India

“…Enhanced root development and plant growth regulation by improvement in water-retention capacity and cluster structures of soil through hydrogel are useful in achieving higher production ( Akelah, 2013 ). Similar results of yield advantage and higher nutrient uptake have been reported by ( Singh et al., 2017 ) in mustard, ( Rathore et al., 2019 ), in pearl millet, and by ( Dai et al., 2017 ) in sorghum.…”

“…The hydrogel application increases plant survival ( Woodhouse and Johnson 1991 ) and dry matter production and prolongs the stay-green quality ( Callaghan et al., 1988 ), particularly under moisture, constrained situations ( Yangyuoru et al., 2006 ). The enhanced nutrient availability through enhanced longevity of water availability and uptake improves plant growth and yield attributes in hydrogel amended plots ( Rathore et al., 2019 , Chen et al., 2003 ). In the present investigation, the hydrogel application enhances the seed yield of mustard by 15.6% over no hydrogel application.…”

“…A better plant canopy, higher chlorophyll content, number of branches plant −1 , siliquae plant −1 , and seeds siliqua −1 with the addition of hydrogel has been also reported in soybean ( Sivapalan 2011 ). The application of super absorbent polymers improves cell membrane development, leaf area index, leaf area duration, chlorophyll, and protein content by balancing nutrient substances and higher CO 2 fixation through prolonged stomata opening ascribes for the increase in yield attributes of mustard ( Dexter and Miyamoto 1995 ; Rathore et al., 2019 ). Moisture deficiency at the critical stages reduces the plant crown diameter and at the siliquae development stage, even if siliquae formation is there, the siliquae length significantly reduces.…”

“…The sound management practices for rapeseed-mustard are needed for efficient use of limited moisture, available during the crop season especially at critical stages of crop growth, high evaporative demand (2–6 mm day −1 ), low (<0.25%) soil organic carbon, and poor crop management, which are restricting the national average productivity of oilseed Brassicas to 1.09 t ha −1 , as compared to the world's average of 1.83 t ha −1 ( DRMR, 2013 , Rathore et al., 2019 ; Mandal et al., 2011 ) in India. Efficient irrigation water management in rapeseed-mustard has an enormous impact on seed and oil products and also on response to other applied inputs ( Rathore et al., 2019 ). Besides efficient irrigation water management, improved rainwater and soil moisture conservation help in enhancing crop growth and yield as well.…”

Diversified agroforestry systems improve carbon foot printand farmer’s livelihood under limited irrigation conditions

“…Similar was the trend with MWUE (Table 4 and Fig 1). Under arid and semi-arid conditions,Rathore et al (30) also reported higher WUE ofmustard crop. This was due to higher productivity of karonda based AFS and better prevailing market prices of the karonda fruits.…”