Evaluation of lowcost agronomic techniques for sustained rice production
Loading...
Files
Date
1985
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Department of Agronomy, College of Horticulture, Vellenikkara
Abstract
Three field experiments were conducted at the Regional Agricultural Research
Station, Pattambi, Kerala to evaluate some of the low cost agronomic techniques for
sustained rice production during the period from 1982 to 1985. In the first
experiment the performance of IR 42, a rice variety suited to low fertility conditions
was assessed under varying levels of nutrition and spacing. Fertilizer, age of
seedlings and planting density, for IR 42 were the experimental variables for the
second experiment. In the third trial, azolla was evaluated as a low cost biofertilizer
for IR 42. The first and third trials were laid out in split plot design while the second
trial in factorial RBD.
The rice cultivar IR 42 proved its mettle under the low fertility conditions. In fact, it
gave an average yield of 2.78 t ha-1 in virippu and 2.32 t ha-1 in mundakan without
any fertilizer application.
A plant population of 33 hills m-2 (spacing 20 x 15 cm) in conjunction with full dose
of fertilizer of 90 : 45 :45 kg NPK ha-1 recorded substantially more grain yield of
4.24 and 3.20 t ha-1 in virippu and mundakan seasons, respectively. Relatively lower
grain and straw yields were registered by the treatment 100 hills m-2 (spacing 20 x 5
cm) at all levels of fertilizer application. The net return and benefit cost ratio were
more in the former combination.
Increasing the seedling number hill-1 from two to four or six was also found to be
beneficial for this variety. At lower levels of fertilizer six seedlings hill-1 recorded
higher grain yields. However, at higher levels four seedlings hill-1 was found to be
superior.
During virippu season planting of 35 days old seedlings was found to perform better
compared to 30 and 25 days old seedlings whereas in mundakan season, 30 days old
seedlings were found preferable in terms of grain yield.
Recommended dose of fertilizers (90 : 45 : 45 kg NPK ha-1) with azolla @ 10 t ha-1
and 75 per cent of the same with azolla @ 15 t ha-1 recorded similar grain yields
indicating that an extra dose of 5 t of azolla ha-1 could substantially reduce the
chemical fertilizer requirement and save as much as 25 per cent of the fertilizer. The
benefit cost ratios were almost equal in both the combinations while the return per
rupee invested was more in the latter combination. The finding appears to caution
against excessive use of azolla expecting better exploitation of all the benefits
attributed to it. Nevertheless, data on the residual fertility of the soil after each crop
indicate that residual fertility was higher in the plots receiving full dose of fertilizer
along with the highest level of azolla, 20 t ha-1.
Description
PhD
Keywords
null
Citation
171042