Book of Extended summaries ISDA

International Conference on Reimagining Rainfed Agro-ecosystems: Challenges & Opportunities
during 22-24, December 2022 at ICAR-CRIDA, Hyderabad
either before or after harvest is a common practice which not only reduces the amount of
surface organic matter, soil organic carbon (SOC), essential nutrients, and microbial count
but also causes environmental pollution. Reports on dynamics of SOC in different pools and
their relationship with soil biology under climate smart management systems in sugarcane
cropping system is very scanty. Keeping this in view, a field experiment was conducted to
evaluate the effects of reduced tillage, residue and nutrient management practices on soil
organic carbon pools, soil biological properties and their interrelationships with system yield
after six years of continuous cultivation of sugarcane in Semi-arid regions of India.
Methodology
During 2016-2022, a field experiment was conducted at ICAR-National Institute of Abiotic
Stress Management, Baramati, Maharashtra with hot and semi-arid climate. Majority of
agricultural area is rainfed with low annual rainfall (584 mm) received mostly in June-
December restricted to south-west (70%) and retreating (21%) monsoons. The predominant
medium black soil (≤ 60 cm depth) at the site was sandy clay in texture (sand, silt, clay, 55.6,
8.3, 36.1, respectively). The pH (1: 2.5 soil: water suspension), EC, available N, P, K and
organic C of soil were about 8.1, 0.26 dS m -1 , 172.2, 18.2, 143.8 kg ha -1 and 6.7 g kg -1 ,
respectively. The experiment was laid out in split-split plot design and replicated thrice with
tillage as main plot treatments viz., conventional tillage (CT) and reduced tillage (RT);
residue (R) managements practices i.e. RR (residue retention) and RB (residue burning) in
sub plots and three nutrient management practices of different ratios of recommended doses
of fertilizer (RDF) in sub-sub plots i.e. 25: 75 (N1); 50: 50 (N2); and 75: 25 (N3) during
basal and subsequent fertigation, respectively. Soil samples were collected from (0-15) and
(15-30) cm soil depths after six years of the study i.e. after harvest of one fresh and four
ratoon sugarcane crops. The soil samples were analyzed for SOC content, its pools, soil
enzymes and microbial counts following the standard operating procedures as followed in
Datta et al., 2015 and Choudhary et al., 2018). Statistical analyses were executed with general
linear models (GLMs) using the “Agricolae” package of R (R Development Team, 2011).
Results
Soil enzymes and microbial population
Soil dehydrogenase activity (DHA), alkaline phosphatase activity (APA) and ß-glucosidase
activity (BGA) were significantly affected by tillage, residue and nutrient management
practices (Table 1). In the (0-15) cm soil layer, reduced tillage had 322, 36 and 55% higher
DHA, APA and BGA, respectively than CT. Plots with residue had 83% higher DHA as
compared to residue removal plots. A similar trend was seen for APA and BGA with 16%
higher activity in RR plots than RB. For nutrient management practices, the enzyme
activities were found in order of N2 (50% RDF as basal and rest 50% through fertigation) >
Resource conservation and rainfed agriculture
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