CALIBRATION AND VALIDATION OF CROPGRO (DSSAT 4.6) MODEL FOR CHICKPEA (Cicer arietinum L.) UNDER DIFFERENT HYDRO-THERMAL REGIMES OF MIDDLE GUJARAT REGION
Loading...
Date
2017
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
AAU, Anand
Abstract
A field experiment was conducted for two consecutive years
2014-15 and 2015-16 with three dates of sowing and four irrigation levels.
The experiment was laid out in strip plot design. The sowing dates D1- 15th
October, D2- 30th October and D3- 15th November as main plot treatments
with irrigation levels as sub plot treatments namely I1- Irrigation at critical
growth stages, I2- 0.4 IW: CPE, I3- 0.6 IW: CPE and I4- 0.8 IW: CPE to
calibrate and validate the CROPGRO (DSSAT 4.6) model for chickpea
(Cicer arietinum L.) under different hydro-thermal regimes of middle
Gujarat region. Significant differences in the seed yield were observed
during both the years individually and also pooled. However, the
differences were higher for D2 (2179 kg ha-1) than D3 (2079 kg ha-1) and D1
(1853 kg ha-1) dates of sowing during 2014-15. Whereas, during 2015-16
the differences in seed yield of chickpea sown on D2 (2075 kg ha-1) being at
……………………………………………………………………………….Abstract
ii
par with D3 (1949 kg ha-1) sowing were significantly higher than D1
(1729 kg ha-1). Under pooled results significantly highest seed yield
(2126 kg ha-1) was recorded under D2 sowing. Among the different
irrigation treatments, the differences in the seed yield were significantly
higher for I3 (2230 kg ha-1) irrigation treatment being at par with I1
(2064 kg ha-1) irrigation treatment than I4 (1992 kg ha-1) and I2
(1861 kg ha-1) respectively, during 2014-15. Whereas, the seed yield of
chickpea for irrigation treatment I3 was significantly higher (2153 kg ha-1)
being at par with I1 (2013 kg ha-1) irrigation treatment than I4
(1861 kg ha-1) and I2 (1728 kg ha-1) during 2015-16. Under pooled results
significantly highest seed yield (2191 kg ha-1) was recorded under I3
irrigation treatment as compared to rest of the irrigation treatments.
By studying the role of weather variables on chickpea in terms of
seed yield, it is noticed that best performance of D2 sowing was observed
and this was mainly attributed to more congenial weather i.e Tmin ranged
from 8.6 to 22.6 0C during 2014-15 and it ranged from 6.6 to 20.7 0C
during 2015-16, while Tmax ranged from 23.8 to 37 0C during 2014-15
and 27.3 to 38.8 0C during 2015-16 that prevailed during this period as
compared to the weather that prevailed during the D1 and D3.
The soil moisture content under I2 irrigation treatment experienced
<10 % for higher duration as compared to I4 irrigation treatment under all
the dates of sowing. This soil moisture stress was clearly reflected in lower
biomass, LAI and seed yield in all the dates of sowing.
……………………………………………………………………………….Abstract
iii
The periodic dry matter production was observed higher under I4
irrigation treatment as compared to other irrigation treatments in all the
dates of sowing during both the year of experiment due to higher
vegetative growth and leaf area index due to higher frequency of irrigation
levels. While it was found lower under I2 irrigation treatment as compared
to other irrigation treatment in all the dates of sowing during both the year
due to higher water deficit and lower frequency of irrigation.
Therefore, finally it is concluded that sowing of chickpea should be
done on 30th October to achieve higher seed yield. Irrigation at 0.6 IW: CPE
is preferable under 30th October sowing.
The overall performance of the model based on the test criterion to
evaluate the CROPGRO- Chickpea model for phenological and yield
attributes of three dates of sowing D1- 15th October, D2- 30th October and
D3- 15th November and four irrigation levels I1- Irrigation at critical growth
stages, I2- 0.4 IW: CPE ratio, I3- 0.6 IW: CPE ratio and I4- 0.8 IW: CPE ratio
clearly indicated that simulation for seed yield was better with reasonable
error. The decrease in seed yield with early and delayed sowing as
observed in experiment was well simulated by the model. However, under
higher irrigation frequency, the model simulated moderately higher seed
yield. Model output showed that the simulated values of phenology,
growth parameters and seed yield of chickpea were close to the
corresponding observed values. Thus, the model could be used to predict
the seed yield accurately under different management conditions
Description
Keywords
agriculture, meteorology, method