Weed dynamics and phytosociological studies in diversified cropping systems
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Date
2022-12-15
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CSK HPKV, Palampur
Abstract
The study was carried out in a continuing experiment under AICRP-IFS at Bhadiarkhar farm CSK
HPKV, Palampur. Ten cropping systems C1–“Maize – wheat”, C2 – “Maize –Gobhisarson + Toria”, C3–
“Dhaincha–Early cabbage – Frech bean”, C4– “Sunhemp – Vegetable Pea - French bean”, C5–“Maize + Soybean –
Chickpea + Linseed”, C6– “Rice – Wheat + Gram”, C7– “Hybrid Sorghum + Hybrid Bajra – Oats + Sarson”, C8 –
“Hybrid Sorghum + Hybrid Bajra – Ryegrass + Berseem”, C9 – “Baby corn – Broccoli - French bean”, C10 “Okra
– Turnip - Tomato” in a randomized block design with three replications were evaluated for appraisal on weeds
floristic diversity, phytosociology, phenology, weed dynamics, NPK depletion and yield loss. Soil of experimental
field was silty-clay loam in texture and acidic in reaction with PH 5.38. Weed flora was composed of 13 species in
kharif 2021 viz. Ageratum conyzoides (24%), Cyperus spp. (20%), Phyllanthus niruri (11%) and Galinsoga
parviflora (10%) were the dominating weed species and remaining weed species were Alternanthera
philoxeroides, Artemesia vulgaris, Commelina bengalensis, Coronopus didymus, Digitaria sanguinalis,
Echinochloa spp., Ipomoea spp. and Monochoria vaginalis. During rabi 2022,13 weed species were reported, out
of them dominating weed species were Poa annua (25%), Coronopus didymus (15%), Spergula arvensis (14%)
and Trifolium repens (10%)and the other weed species were Anagallis arvensis, Avena fatua, Cynodon dactylon,
Phalaris minor, Lolium temulentum, Raphanus spp., Stelleria media and Vicia sativa. Ageratum conyzoides was
the most important weed during the kharif season with IVI value ranging from 35.2 to 100.1 under different
cropping systems. This was followed by Cyperus spp. ranging from 18.1 to 67.1 and Galinsoga parviflora ranging
from 26.0 to 62.3. During rabi season, the most important weed was Poa annua with IVI value of 40.8 to 70.4 in
cropping systems. This was followed by Coronopus didymus ranging from 26.1 to 65.6 and Spergula arvensis
ranging from 15.8 to 56.3.
Simpson’s index of diversity and Simpson’s reciprocal index indicated higher weed diversity under C3 –
“Dhaincha – Early cabbage – Frechbean” followed by C4 – “Sunhemp – Vegetable Pea - French bean” and C5 –
“Maize + Soybean – Chickpea + Linseed for kharif season. For rabi season Simpson’s index of diversity and
Simpson’s reciprocal index indicated higher weed diversity in C3 cropping system– “Dhaincha – Early cabbage –
Frech bean” followed by C4 – “Sunhemp – Vegetable Pea - French bean” and C6 – “Rice – Wheat + Gram”.
Majority of the kharif weeds emerged during June reached flowering between July and August, seed setting and
maturity in September and Rabi weeds emerged during October and November also,flowering occurred during
January and February, maturity during March and April. Nutrient depletion by weeds ranged from 39.8 – 43.9
kg/ha N, 10.4 – 15.6 kg/ha P and 19.3 – 25.5 kg/ha K under different cropping systems, minimum under cropping
system C1 – “Maize – wheat” for N, C2 – “Maize –Gobhisarson + Toria” for P and C7 – “Hybrid Sorghum +
Hybrid Bajra – Oats + Sarson” for K and maximum under cropping systemC7 – “Hybrid Sorghum + Hybrid Bajra
– Oats + Sarson” for N, C10 “Okra – Turnip - Tomato for P and C3– “Dhaincha – Early cabbage – Frechbean” for
K. For kharif season, percent yield loss was found to be higher in C6 – “Rice – Wheat + Gram” and for rabi season
it was higher in C9 – “Baby corn – Broccoli – French bean” cropping system. Weeds inflicted huge yield losses
ranging from 38.46% in C1 Maize – Wheat to 82.20% in C8 Hybrid Sorghum + Hybrid Bajra–Ryegrass + Berseem.