Mitigating moisture stress in Indian mustard (B. juncea) through polymer

Abstract

Under the current changing climate scenario, the development of drought mitigation strategies is the need of the hour to
enhance water productivity and minimize the yield losses in the Indian mustard (Brassica juncea L.). To address the
issue, a field experiment was conducted during 2018-19 to evaluate the field efficacy of the superabsorbent polymer
(SAP: Pusa hydrogel) and its application rates 1.5, 2.5 and 5.0 kg ha-1 and compared with control under moisture stress
and normal moisture conditions in a randomized complete block design and replicated thrice. The values of growth, yield
attributes and seed and stover yields of the Indian mustard were significantly (P=0.05) reduced due to moisture stress,
but improved with the use of SAP. The maximum seed yield (2.88 t ha-1) and stover yield (6.84 t ha-1) were obtained at SAP
@ 5.0 kg ha-1 with normal moisture which were improved by 48.4 % and 20.6 % over the control, and 15.2–36.5 % and 9.1–
16.3 % over the SAP levels (1.5–5.0 kg ha-1) of moisture stress regime, respectively. This indicated that application of
SAP (5.0 kg ha-1) reduced the yield penalty due to moisture stress. Seed yield with 5.0 kg SAP ha-1 improved by 12.11%
and 3.97 % under moisture stress and normal moisture regimes, respectively over the 2.5 kg SAP ha-1. This suggested
that application of 5.0 kg SAP ha-1 under moisture stress and 2.5 kg SAP ha-1 under normal moisture was found beneficial
in enhancing the seed yield of mustard. The water productivity (WP) was comparatively higher (~ 6.6 %) under moisture
stress over 1.32–1.67 kg m-3 recorded under normal moisture. The maximum WP under both the moisture regimes were
obtained with the SAP @ 5.0 kg ha-1. The WP improved by 10.6, 20.4 and 26.5 % under normal moisture and by 11.2, 18.7
and 32.8 % under moisture stress with 1.5, 2.5 and 5.0 kg SAP ha-1, respectively over the respective controls. This
signifies the beneficial role of SAP in achieving higher WP levels, particularly under moisture stress. Thus, the study
recommends the use of SAP @ 2.5 kg ha-1 under normal moisture and 5.0 kg ha-1 under moisture stress to achieve the
maximum seed yield and water productivity with concomitant saving of 16-20 % water with the later