Book of Extended summaries ISDA

International Conference on Reimagining Rainfed Agro-ecosystems: Challenges &
Opportunities during 22-24, December 2022 at ICAR-CRIDA, Hyderabad
chemical fertilizers in balanced quantity is important. But looking into continuous increasing
prices of fertilizers, it becomes necessary to minimize the expenses on fertilizers by using
alternative sources like farmyard manure, crop residues, green manuring for sustaining the
crop yields and soil fertility. The long-term integrated application of chemical fertilizers with
organic manures improves soil physical and biological properties, soil fertility and crop
yields.
Methodology
This research work was initiated during the year 2011-12. Every year rabi season, cotton (KC
3) sowing has been taken in black soil farm (Vertisols) at the last week of September to find
out the long-term effect of nutrient and combined effect of organic and inorganic nutrients on
crop yield and soil fertility. The Kovilpatti region is the representative of dryland agriculture
in Tamil Nadu. The depth of the black soil varies from 110 to 150 cm with the infiltration
rate of 0.9cm hr -1 . Soil develops typical cracks with at least one cm wide and reaching a
depth of 50cm or more in the period of moisture stress. Considering the mechanical fraction,
the soil is clay ley with clay content of 46.4 to 61.2 per cent, 10.0 to 17.5 per cent silt and
12.6 to 24.5 per cent coarse sand. The soil bulk density varies from 1.21 to 1.36 kg m -3 with
the field capacity of 35 per cent and permanent wilting point of 14 per cent (Sunflower as an
indicator plant). The soil has sub angular blocky structure with pH generally neutral to a
tendency towards alkalinity at lower depths (7.8 to 8.2). The experiment was conducted in
randomized block design (RBD) replicated thrice under rainfed condition. The treatments
comprised of T1 - Control, T2 - 100 % RDF (40:20:40 NPK kg ha -1 ), T3- 50 % RDF (20:10:20
NPK kg ha -1 ), T 4- 50 % N (crop residues), T 5 -50 % N (FYM), T 6 - 50 % inorganic N+ 50%
organic N (crop residues) + P (50%) + K (50%), T7 -50 % Inorganic N+ 50% organic N
(FYM) + P (50%) + K (50%), T 8 -100 % RDF + 25 kg ZnSO 4 ha -1 and T 9 - FYM @ 12.5 ha -
1
. As per the treatment schedule, the full dose of inorganic fertilizers and organic manures
were applied as basal application. The initial soil status was of pH 8.13, EC 0.28 (dS m -1 ),
and available NPK was 105, 11.2.and 345 kg/ha respectively
Results
In rainfed vertisols condition, long term application of 100 % RDF + 25 kg ZnSO4 ha -1
recorded higher total plant nutrient uptake viz., nitrogen uptake (15.6 kg ha -1 ), phosphorus
uptake (3.2 kg ha -1 ), potassium uptake (17.1 kg ha -1 ) and zinc uptake (18.20 mg kg -1 ) and it
was followed by the treatments applied with 50 % Inorganic N+ 50% organic N (FYM) + P
(50%) + K (50%) (Fig.1). Deshmukh et.al (2016) reported that the significantly higher uptake
of nitrogen (40.30 kg ha 1), phosphorus, potassium (39.30kg ha-1), sulphur and zinc was
recorded with the application of 125 % RDF (75:37.5:37.5 NPK kg ha -1 ) + Zinc @ 2.5 kg ha -1
Sustainable soil management for resilient rainfed agro-ecosystem: conservation agriculture, organic farming,
INM, soil-microorganisms-plant interactions
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