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Impact of Summer Monsoon Precipitation on Winter Crop
Yields Across India
-- Preethi and J V Revadekar
The Indian economy largely depends on
agriculture. The winter cropping season, also known as rabi, starts after the summer monsoon and continues up
to spring or early summer months. Rainfall occurring at the
end of summer monsoon season provides stored soil moisture for rabi crops, which are sown in the
post-monsoon season (October-November). Variation in the frequency of heavy rain spell
has a profound impact on the ecosystem. Therefore, an attempt
has been made in this study to analyze the frequencies of moderate to
very heavy precipitation events in India during the
summer monsoon season (June through September) using
a high resolution (1° x 1° latitude-longitude) gridded daily rainfall datasets prepared by
the Indian Meteorological Department (IMD) and its association with rabi foodgrain yield, collected from the
DES (2006). The study indicates that a variation in
the foodgrain production during rabi season
in India is strongly linked to the variation in frequencies with respect to various fix threshold values of
rainfall and shows positive correlation coefficients.
However, its spatial coverage varies from threshold to
threshold. Spatial coverage of positive correlations for
the number of rainy days with rabi foodgrain production is
more than the total precipitation of the summer monsoon season. Also spatial coverage of correlation
coefficients and its level of significance decreases with increase in
the threshold value of rainfall with respect to
which frequencies are computed.
© 2009 IUP. All Rights Reserved.
Soil Fertility and Plant Diversity
in Sabal Forest Reserve, Borneo
-- Hashim N R
This study highlights soil fertility status as well as plant structural and compositional makeup in
two different forest types after being exposed to different levels of anthropogenic disturbances.
The mineral soil chemical analysis (pH, conductance,
percentage of carbon and nitrogen, Cation Exchange Capacity
(CEC), potassium, sodium, magnesium, calcium, and total and available phosphorus) showed that the
concentrations of the chemical elements were lower than the values of published
results from other studies in Borneo, suggesting a serious habitat degradation due to prior land-use in the forest reserve. In terms of plant
abundance and richness, the logged-over forest fragments were dominated by small
trees, whereas the understorey of tree plantations was composed of dense ferns and sedges with very low tree abundance and species
richness. This study therefore provides important information on the management of soils and plant diversity in
the tropics.
© 2009 IUP. All Rights Reserved.
Increasing Nitrogen Use Efficiency in Rice
(Oryza sativa L.) with Chlorophyll Meter
and Leaf Color Chart
-- M Z Hussain, Shakeel A Khan, T M Thiyagarajan
Low Nitrogen Use Efficiency (NUE) continues to be a problem in wetland rice
situation as nitrogen (N) is subjected to several transformation losses in the rice ecosystem. Chlorophyll meter (SPAD) and
Leaf Color Chart (LCC) can be potentially employed for the precise N
measurement, which is based on the leaf N status to synchronize the timely N application with the crop demand. Two field experiments were
conducted during 1998 and 1999 at Coimbatore, India with the rice
(Oryza sativa L.) cultivars of ADT 36 (short
duration) and ASD 19 (long duration) respectively
for efficient N management based on the leaf N status of rice.
The experiments consisted of four SPAD and LCC-N regimes, blanket N recommendation, green manure N
regime and Controlled Release N (CRN) fertilizer
regimes, which were compared with the zero-N regime.
The technology involves the indirect measurement of leaf N status by the chlorophyll meter and LCC and
N application only if the measured meter value is below the predetermined threshold value. The study
reveals that N requirement with LCC was higher than SPAD for all the time intervals of measurements. In terms
of NUE parameters, LCC was inferior to SPAD-N management,
but the lesser cost of LCC, when compared to SPAD
meter, provides an opportunity as a simple tool for the individual rice farmers to own it. The
study also reveals that the application of controlled release N fertilizer as polymer coatings at the rate of 60%
of blanket N recommendation would save 40% of fertilizer N.
© 2009 IUP. All Rights Reserved.
Residual Phytotoxicity of Chlorsulfuron Applied
in Wheat (Triticum aestivum L.) on Succeeding Crop of Maize
(Zea mays L.)
-- Amarjeet, S S Punia and Ashok Yadav
Field experiment was conducted from 1999 to 2001 to evaluate chlorsulfuron at different doses for
weed control in wheat under different irrigation levels and its residual effect
on the succeeding crop of maize. Chlorsulfuron at 30 g
ha_1 resulted in 71.1% Weed Control Efficiency
(WCE) and 4,630 kg ha_1 grain yield, which was statistically
on a par with chlorsulfuron applied at 40 or 50 g
ha_1. The grain yield of wheat was increased by increasing the number of
irrigations from three to five (i.e., 4,081 to 4,783 kg
ha_1). The phytotoxicity decreased, and
the growth and yield of maize increased with the corresponding increase in the number
of irrigations applied to wheat. Phytotoxicity to maize increased with each successive increase in the dose
of chlorsulfuron applied in wheat. Chlorsulfuron at 30 g
ha_1 resulted in 49.0% toxicity to
maize, which was significantly lower than toxicity under chlorsulfuron at 40 or 50 g
ha_1. The toxicity at 20 g
ha_1 was 29.3%. Consequently, the fodder yield of maize reduced with
an increasing dose of chlorsulfuron applied in
wheat. Chlorsulfuron at 20 and 30 g
ha_1 caused 24 and 52% reduction in fodder yield of
maize, as compared to untreated control. The reduction in yield further increased to the extent of 67 and 83%, where
chlorsulfuron was applied at 40 and 50 g
ha_1, respectively, in wheat. In order to achieve satisfactory weed
control, chlorsulfuron at 20-30 g ha_1 could be applied in
wheat, but maize should not be grown in rotation.
© 2009 IUP. All Rights Reserved.
Rainwater Harvesting and Management Technology for
New Livelihood of Submontane N-W
Tract Zone Farmers of India
-- M S Hadda and Sanjay Arora
The N-W (northwestern) tract zone of India receives high precipitation rate varying from 850-1100 mm,
but suffers from water scarcity during winter season (October to March). Due to non-availability of
irrigation facilities and deep to very deep water table in the area, the alternative method is to explore minor
irrigation potential through rainwater harvesting structures/tanks or through effective water-conservation measures
or roof top. A cost-effective rainwater harvesting tank varying in capacities from 0.80 ha m to as high as 1.20 ha
m capacity has been developed in the districts of Solan and Hoshiarpur in Himachal Pradesh and
Punjab, respectively. However, farmers may have the option to design
a tank of suitable capacity as per the water requirements of crops intended to be cultivated and also for other diversified use of stored water for
crop production, fish rearing, kitchen garden purposes and other uses during winter season (October to March)
that suffers mainly from stress period. The designed water harvesting tanks were made up of clay,
Low Density Polyethylene (LDPE) black agri-film and brick lining in order to reduce the seepage losses. Using the
stored water judiciously and economically in various farm activities is most acceptable especially for the cultivation
of ginger and tomatoes, etc. This economically viable and easily adoptable technology needs to be
disseminated and popularized among large sections of
farmers. This paper describes all aspects, including cost of
preparation, size and capacity of water harvesting tank, water loss, lining material used, water productivity and
diversified use of stored water. In addition, the paper highlights the future strategies to be followed in the area.
© 2009 IUP. All Rights Reserved.
Research Note
Sediment Observation in River Basins:
A Case Study
-- K Purandara and A V Shivapur
© 2009 IUP. All Rights Reserved.
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November '09
