Validation and sensitivity analysis of InfoCrop simulation model for growth and yield of Indian mustard varieties at Allahabad

Field experiment was carried out at SHUATS, Allahabad, to study validation and sensitivity analysis of InfoCrop model with the data sets generated respectively during Rabi season of 2016-17. The main plot treatments and sub-plot treatment consisted three dates of sowing and cultivars (D1-25th October, D2-5th November and D3-15th November) and (V1- Parasmani, V2- Varuna and V3- SRM 777) using split plot design. The results revealed that simulation of growth and yield parameters were compared with observed data and results concluded that the model overestimates all the parameters within the acceptable range (


INTRODUCTION
Rapeseed-mustard (Brassica spp.) is a major group of oilseeds crop of the world being grown in 53 countries across the six continents, Indian mustard (Brassica juncea) is the second important oils eed crop in India after groundnut sharing 27.8% in India's oilseed production. Indian-mustard is much sensitive to climatic variables; hence, climate change could have a significant effect on its production. One month delay in sowing fro m mid -October resulted in the loss of 40.6 percent in seed yield (Lallu, et al., 2010). Weather parameter is very important which influence growth and yield of a mustard crop, therefore, largely governed by the change in growing environment such as date of sowing and water availability. Leaf area index plays an important role for crop growth based on its interception and utilization of PA R (Photosynthetically active rad iation) for producing dry matter (Ku mar et al., 2007) and with the delay in planting date, the higher mean temperature was experienced during flo wering wh ich led to accelerat ing the decrease of LAI and reduction of the flo wering period (Poureisa and Nabipour, 2007).
According to IPCC assessment report (A R4), global average temperature has increased by 0.74 0 C over the last 100 years and projection of an increase in temperature about 1.8 to 4 0 C by 2100. Global losses may account for 1 to 5 percent of GDP, but developing countries with tropical and sub-tropical climate are likely to suffer more losses. Temperature increases are likely to be higher during winter season and precipitation is likely to decrease (IPCC, 2007). IPCC and its global studies indicate that considerable probability of loss in crop production in India with increases in temperature (IPCC, 2014). Info Crop simu lation model is one of the user-friendly systems, dynamic crop growth model developed under Indian condition. This model has the capability to estimate the actual and potential yield, y ield gaps and also to assess the impacts of climate variab ility and climate change. The model simu lates the crop growth processes viz., phenology, photosynthesis, respiration, leaf area g rowth, assimilates partitioning, source-sink balance, nutrient uptake partitioning and transpiration ). Info Crop model has been used for simulating potential rain-fed yields. It is used to optimize management, dates of planting, variety, irrigation and nitrogen fertilizer, assessing interactions among genotype, environment, management, and pests, yield forecast, yield loss assessment due to pests and greenhouse gas emissions (Aggarwal et al. 2004).
Study of the impact of climate change on crops needs simulat ion model, as it provides a means to quantify the effects of climate, soil, and management on crop growth, productivity and sustainability o f agricultural production. These tools can reduce the expensive and timeconsuming field experimentation as they can be used to extrapolate the results of research conducted in one season or location to another season, location, or management (Boo miraj et al. 2007). Boo miraj et al. (2010) observed that model can successfully simulate growth and yield of the mustard crop across different locations in India. The simu lated yield o f mustard was found to be sensitive to changes in atmospheric CO2 and temperature variation. The objectives of this study, to quantify InfoCrop model on the mustard crop at Allahabad conditions, which show considerable potential to evaluate crops, varieties, and genotypes of mustard, cropping pattern and genetic potential for y ield. The scientific informat ion on simulation of growth and yield in mustard crop using modeling in Uttar Pradesh is lacking. Hence, keeping in v iew the impo rtance of the study, the present investigation was carried out.

II. MATERIALS AND METHOD Experi mental Details
The exp erimental field d ata (2016-17) o f A llahab ad station co mp ris ing th ree dat es o f so wing (Rab i: D1 -25 th Oct ., D2 -5 th Nov . and D3-15 th Nov.) and variet ies (V1 -Paras man i, V2 -Varuna and V3 -SRM 777) th rough th e field experiment laid o ut sp lit -p lo t d esign was used fo r model calibrat ion and validat ion . The package and pract ices fo r Ind ian mustard cu lt ivat io n were fo llo wed as per th e Sam Higg inb otto m Un ivers ity o f Ag ricu ltu re, Techno logy, and Sciences , A llahab ad. Validat ion o f model was p erfo rmed by usin g d ifferen t data sets on such as ph eno logy , total d ry matter, g rain y ield , harv estin g ind ex and t est weig ht fro m th e field exp eriment con ducted at Sam Higg inbot to m Un ivers ity of Agriculture, Technology and Sciences, Allahabad.  Table 1.
Calibrati on of the model The models were run and validated b y co mparing th e pred icted output with observ ed paramet ers . Dev iat ion of p red icted fro m observ ed was calcu lat ed and accu racy of the mod el to p red ict d ifferent crop p arameters was quant ified , then the s imu lat ed was fo r th e fu rther study . The genet ic coefficient o f mustard fo r In fo Crop mod el is given in Table 2. Validation Validation of model will be performed by using different data sets on phenology, biological yield, seed yield, harvesting index and test weight from experiments conducted at Research farm, School of Forestry and Environment, SHUATS, Allahabad. For judging the performance of the InfoCrop model, validation results on major crop growth parameters such as phenology during crop growth and grain yield will be tested using various statistical parameters viz., mean absolute error (MA E), mean bias error (M BE), root mean square error (RM SE), and error %.

Sensitivity analysis
The increase in CO2 concentration fro m 390 to 490 ppm enhanced the crop yield. Increase in CO2 fro m 390 to 490 pp m with no change in temperature has resulted in 13-32 % increase in yield of mustard but further increase in CO2 concentration reduced the percent increase in yield. Increase in rainfall during crop season, indicated the scope for improved dry matter production and increase in grain number.

Temperature
The increased in daily maximu m temperature up to 3 ºC resulted in increased in yield of mustard (figure 1). In plants, warmer temperature accelerates growth and development leading to less time for carbon fixation and biomass accumulat ion before seed set resulting in poor yield (Rawson, 1992;Morison, 1996)

IV.
CONCLUSIONS Simu lation of mustard phenology, growth and yield attributes by InfoCrop model was within the acceptable limit . Therefore, the validated InfoCrop model can further be used for prediction of crop growth, phenology, potential and actual yield of the mustard crop under changing climate scenarios.