Determination of sowing window for kharif maize in Punjab, India using sensitized, calibrated and validated CERES-Maize model

Crop models help in optimizing the farming practices under climate change scenarios. The CERES-Maize was sensitized for genetic coefficients (P1, P2, P5, G2, G3 and PHINT) using sensitivity index (SI) through mathematicaland graphical approach. The sensitized range was used for calibrating the model for maize hybrids Punjab Maize Hybrid1 (PMH1) and Punjab Maize Hybrid2 (PMH2) for the year 2018 and further validated for the year 2019 using statistical indices. A good coefficient of determination (R 2) for PMH1 and PMH2 was obtained for anthesis (0.82, 0.80), maturity (0.67, 0.94), yield (0.95, 0.95) and Leaf Area Index (LAI) (0.85, 0.82) respectively. The Normalized Root Mean Square Error (NRMSE) was found to be excellent (<10%) for all the parameters except LAI where it was good. The model simulated 20th May to 7th June as the optimum sowing window for maize with grain yield / LAI for PMH1 being 5200-6000 kg ha-1 / 2.9-3.2 and for PMH2 being 4200-5400 kg ha-1/ 2.8-3.0. With delay in sowing from June 8th to 18th the grain yield/LAI varied between 5000 - 5400 kg ha-1/3.1-3.4 for PMH1 and 4000 - 5000 kg ha-1/ 2.7-3.2 for PMH2. Delay in sowing after June 7th reduces the grain yield at the expense of profuse vegetativegrowth, i.e. the LAI increases upto June 18th and 24th for PMH1 and PMH2, respectively. The deviation of grain yield and Harvest Index (HI) from their mean for the sowing window, respectively showed depreciation after June9th (-0.31%, -2.31%) for PMH1 and after June 12th (-6.49%, -0.13%) for PMH2. The HI and grain yield decreased while LAI and biomass increased with delayed sowing. The calibrated CERES-Maize model can further be used for analysing the climate change impact on maize in Punjab, India

Calibration, validation and application of AquaCrop model in irrigation scheduling for rice under northwest India

A lot of research work regarding irrigation scheduling in rice has been carried out at global level with the objective of increasing irrigation water productivity (IWP) and sustaining grain yield. Under natural conditions rain disturb the planned irrigation treatments. One way to overcome this problem is to use rain shelters which is a costly affair, crop growth simulation models offer a good scope to conduct such studies by excluding the effect of rain. Very limited studies are available where FAO’s AquaCrop model has been used to develop irrigation schedule for crops. Therefore, a study was conducted using FAO AquaCrop model to develop irrigation schedule for rice having higher IWP. The model was calibrated and validated using the experimental data of field experiments conducting during 2009 and 2010, respectively. The model underestimated the above ground dry biomass at 30 days after transplanting (DAT) in the range of 21.60 to 24.85 %. At the time of harvest the model overestimated the above ground dry biomass within the range 11.58 to 14.34 %. At harvest the values of normalized root mean square error (15.54%) suggested a good fit for the above ground dry biomass and an excellent agreement (3.34%) between observed and model predicted grain yield. The model suggested to irrigate rice transplanted in puddled loamy sand soil on every 5th day to get higher IWP coupled with statistically similar grain yield as obtained with daily irrigation schedule

SIMULATING THE IMPACT OF WITHIN SEASON VARIABILITY IN TEMPERATURE ON GRAIN YIELD OF WHEAT

Within season variability in temperature is a major bottleneck in wheat productivity. This simulation study aimed to evaluate the effects of temperature variability on grain yield of two cultivars of wheat (cv PBW 621 and HD 3086) sown under different dates (early, mid and late) using two dynamic crop simulation models (CERES-Wheat and INFOCROP model) for two locations (Amritsar and Ludhiana). The temperature was increased and decreased by 1.0 to 2.0oC for Amritsar and 1.0 to 3.0oC for Ludhiana from normal during three growing periods, i.e., the whole season, vegetative phase, and reproductive phase. In Amritsar the CERES-Wheat and INFOCROP model predicted that with the increase in temperature by 1.0 to 2.0oC from normal during the vegetative phase, the grain yield may decrease by 0.36-15.23 % and 3.61-19.54 % respectively, during the reproductive phase the grain yield may decrease by 0.67–8.64 % and 3.18-26.76 % respectively and during the whole season the grain yield may decrease by 1.52-27.10 % and 1.91-24.10 % respectively.&nbsp; Among the two cultivars of wheat, cv HD 3086 at both locations performed better under thermal stress environments as compared to cvPBW 621. However, the InfoCrop model predicted that cv PBW 621 performed well in comparison to cv HD 3086 at Ludhiana conditions with an increase in temperature up to 3°C. The simulation results showed that mid November sowing of wheat was better able to counteract the negative impacts of an increase in temperature on wheat as compared to early (October) or late (December) sowing dates

Maize yield projections under different climate change scenarios in different districts of Punjab

The study aimed to find out possible changes in climatic data (temperature and rainfall) from the regional climate model viz. PRECIS(Providing Regional Climates for Impact Studies)under different SRES scenarios (A1B, A2 and B2 scenario) by the mid (2021-2050) and end (2071-2100) century at six locations of Punjab representing different agroclimatic zones and to study their impact on maize yield using the crop growth simulation model.The results revealed that the different zones of the state are expected to be warmer during the mid century and this trend has been projected to continue by the end of century because of increase in maximum and minimum temperature at all the locations.The CERES-Maize simulated significant decrease in duration and grain yield of maize crop under projected climate scenarios. The reduction in the crop duration and grain yield was found to be more under the A1B and A2 scenario (high emission scenario) followed by B2 scenario (low emission scenario)due to adverse effects on crop physiology

Projected climate change under different scenarios in central region of Punjab, India

The regional climate model viz. PRECIS(Providing Regional Climates for Impact Studies) model was used to downscale the future climatic data for the central region of Punjab, India.The projected data for the 21st century under different scenarios was corrected by using the climate data recorded for the 1971-1990 at meteorological station of Punjab Agricultural University, Ludhiana (Central Region of Punjab) and baseline data derived from PRECIS model. The corrected data was then analyzed on annual, seasonal and monthly basis to quantify the changes in maximum and minimum temperature and rainfall. The projected data showed increase inmaximum and minimum temperature where as an irregular trend in rainfall was observed.It was projected that maximum and minimum temperature and rainfall would increase linearly under the A1B scenario for the mid century. At the end of the century, the rise in maximum  and minimum temperature in B2 scenario will continue but at slower rate than the A1B and A2 scenarios. There would be deficit of rainfall by 78 and 30 % during the winter season under the A2 and B2 scenarios of the end century

Effect of inter- and intra-seasonal variations in meteorological parameters on wheat yields in Punjab

A study was conducted to evaluate the effect of variations in meteorological parameters on wheat (Triticum aestivum L. emend. Flori & Paol) yields during 1970-2005 and also as simulated with CERES-wheat model. The technology trend model of historical wheat yields in Punjab indicated that over the past 2 to 3 decades, at Ballowal Saunkhri, Amritsar, Ludhiana, Patiala and Bathinda the wheat yields have increased @ 64.2, 76.3, 62.8, 87.3 and 71.1 kg/ ha/year respectively. An analysis of historical meteorological data and past wheat yields revealed that for January, February and March the most favourable maximum temperatures for wheat yields were in the range of 16.1-18.0 oC, <21.0 oC and 28.1-30.0 oC respectively while minimum temperatures were in the range of 3.1-5.0 oC, 5.1-7.0 oC and 11.1- 13.0 oC respectively. The simulation study using CERES-wheat model revealed that the temperature increase mostly affected the early (October) sown crop during fourth week of January up to first fortnight of March; the timely (November) sown crop during February and March; the late (fourth week of November) sown crop during March; and very late (December) sown crop during March and first week of April. An analysis of historical wheat yields and weekly meteorological parameters at Ludhiana revealed that during the high yield (>5 000 kg/ha) crop years, the maximum and minimum temperatures remained near normal (+ 2oC); the rainfall was also normal or slightly above/below normal under assured irrigated conditions. From mid-February to March, dry and clear weather proves beneficial for grain filling in wheat. On the other hand, during low yield (<4 600 kg/ha) crop years, although the temperatures were favourable but very heavy rainfall showers were received during the anthesis and grain-filling period of wheat crop. The weather also remained cloudy and sunshine hours were invariably below or near normal while the relative humidity remained above (3-10 %) or near normal during most part of the crop season. Hence, these conditions were ascertained to be the most pertinent reason for relatively low-wheat yields

Effect of elevated temperature regimes on growth and yield of rice cultivars under temperature gradient tunnel (TGT) environments

The effect of elevated temperature on rice were studied during kharif 2013 and 2014 using six cultivars of rice (PR-116, PR-118, PR-113, PR-115, PR-121 and PR-122) with two replications within a temperature gradient tunnel in which temperature was elevated from the ambient level (+4.5, +5.0, +5.3, +5.5 and +5.8 °C) for the entire crop growth period. The results revealed that the plant height increased under elevated temperature regimes, although the rate of change varied with cultivars as well as the stages of the crop. Amongst the six cultivars, the plant height was maximum for cv PR-118 (13.9 cm in vegetative stage (VS) and for cv PR-113 (58.5 cm in grain development stage (GDS) and minimum for cv PR-121 (12.4 cm in VS and 51.8 cm in GDS). The overall tiller number under elevated temperature regimes was maximum for cv PR-122 followed by PR-121, PR-113, PR-116, PR-115 and PR-118 in decreasing order. The 1000-grain weight was reduced from the ambient temperature regime by 8.7 to 14.5 per cent and number of grains per panicle was reduced by 30.6 to 46.7 per cent under elevated temperature of 4.5 to 5.8 oC from ambient. Similarly, the grain yield was reduced by 38.3 to 54.5 per cent and biomass yield reduced by 19.7 to 33.6 per cent with increase under temperature 4.5 to 5.8 oC from the ambient environment. Amongst the six cultivars the harvest index was maximum in cv PR-122 (33.0%), i.e., it is most tolerant to heat stress followed by PR-121 (28.3%) and least tolerant were cv PR-116 (20.2%) and PR-115 (18.9%)