IN PLANT GROWTH PARAMETERS AND GRAIN YIELD OF HILL PADDY UNDER MIXED AND
G.B. Pant Institute of Himalayan Environment and Development, Kosi–Katarmal, Almora 263643, Uttaranchal
(Oryza sativa) is one of the major crops of the hills. It is
traditionally cultivated as a mixed crop under rainfed condition during
the “Kharif season” (April – October). The hill natives maintain
at least a hundred variety (landraces) of Paddy by cultivating them as a
mixed crop (Zhardhari, 2000). But the modern concept of farmers is that
field mixtures would reduce product yield and quality. So more and more
farmers are switching over to monocropping of Paddy, which is resulting
in loss of biodiversity and stability of hill agriculture. Crops have
different ability to scavenge nutrients from the soil and divert it into
the harvested portion of the crops. Hence either cropping system is
expected to have an impact on plant growth parameters, nutrient use
efficiency and hence grain yield of individual crops. Limited field
scale information on differences in growth response of hill Paddy when
planted as a mixed and monocrop prompted me to study the growth response
and grain yield of paddy under different cropping system.
|MATERIALS AND METHODS|
A field experiment was carried out at the Institute’s
experimental site (790 38’ 10’’ E longitude 290
38’ 15’’ N latitude and 1150 m above mean sea level) during the
‘Kharif ’ season. The experiment was laid out in a completely
randomized block design with three replicates. The plot size was 1m x 1m
with 0.5m interplot and interblock space. There were three treatments
namely T1 = Paddy (local variety, control), T2 =
Paddy + Foxtail millet (Setaria
italica) and T3 = Paddy + Foxtail millet + Barnyard
millet (Echinochloa frumentaceae).
Local cultivation method was mimicked. Farmyard manure was applied to
the plots at a rate of 1000 kg ha-1. The seeds of all the
three crops were broadcasted on the same day in their respective plots
at a rate of 200 kg seed ha-1. The soil was mixed with the
help of a shovel and water was sprinkled on the plots. Seeds of all the
three crops (Paddy, Foxtailmillet and Barnyardmillet) germinated within
7 - 12 days. Observations were recorded on plant height, tillers /
plant, total biomass (shoot + root) at an interval of 20 days from the
date of sowing at six dates. Grain yield was recorded at harvest. All
data were analysed for statistical significance according to Snedecor
and Cochran, (1989).
|RESULTS AND DISCUSSION|
number per plant, shoot height, shoot dry weight and root dry weight are
examined across the cropping season. Tillering pattern is a dynamic
process and deciding factor for production of spike bearing tillers. It
is an important trait associated with the productivity of cereal crops
e.g. Paddy. Significant differences in tiller number were observed due
to differences in crop combinations (Table 1). The tiller number reduced
due to stress in mixed cropping. The tiller number reduced by 15.76%
when Foxtail millet was grown with Paddy and it recorded a reduction of
17.64 % when Barnyard millet was grown with Paddy and Foxtail millet.
in shoot biomass are significant. Shoot dry weight reduced by11.05% in
treatment 2 and 40.09 % in treatment 3. Average shoot height also
fluctuated due to mixed cropping. The relationship between tiller
number, root dry weight and shoot dry weight are examined. The
relationships is positive and significant between tiller number and
shoot biomass and root biomass (0.69
and 0.88 being the ‘r’ values under control, 0.72 and 0.80 under
treatment 1, 0.45 and 0.75 under treatment 2 respectively, n = 18).
Kawashima (1968) and Cheema et al. (1979) also reported positive
correlation between tiller number and root biomass.
P = Paddy
P + F = Paddy +
Foxtail millet (treatment 1).
P + F + B =
Paddy + Foxtail millet + Barnyard millet (treatment 2).
Root biomass under control and treatments is also examined. The
maximum root biomass is recorded under control (monocropping system).
The relation between root biomass and shoot biomass is positive and the
correlation coefficient highly significant, (r-values 0.87, 0.78 and
0.59 in control, treatment1 and treatment 2 respectively, n = 18).
grain yield and plant biomass is reduced considerably when cultivated
with millets compared to the pure stand of Paddy (Table 1). Such
reduction is due to decrease in plant stand compared to that of sole
cropping of Paddy. Similar results were obtained in grain yield of
Finger millet by Siddeswaran et al. (1989). However the combined grain
yield of Paddy and millets (treatment 1)
(2323.40 kg ha-1) is much higher when compared with
sole cropping of Paddy. Paddy + Foxtail millet (treatment 2) combination
recorded the second highest productivity (2312.66 kg ha-1).
stress is an important factor affecting the productivity of rainfed
upland rice grown in nearly 6 million ha of land in India, on the other
hand millets are known to be drought resistant. Early cessation of
rainfall and limited availability of soil moisture due to its loss
through surface runoff and poor water holding of soils lead to terminal
stress and result in fewer grain number and poor grainfilling (Krupp et
al., 1972). Similarly root system and its development are strongly
influenced by soil edaphic factors (Mambani et al., 1990; Sharma et al.,
1994). Temperature and concentration of reserve food affects growth
rate. The extent to which internal and external factors influence the
growth rate differs between species and reflects adaptation processes (Hsiao
et al., 1976). The variations in plant growth parameters and grain yield
are usually attributed to competition for resources such as light water
and nutrients by different species. Complementarity in resource use
between mixed crop components can limit competition between them and can
lead to higher yields per unit land (Willey, 1990; Liebman 1995).
Similar results are obtained in the present study also.
|I thank Dr. P. P. Dhyani, Scientist Incharge, INHI Core and The Director, G. B. Pant Institute of Himalayan Environment and Development, Kosi–Katarmal, Almora, for encouraging me and providing me the necessary facilities.|
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