Heliothermal Units Research Articles

Effect of Sowing Dates and Wheat Cultivars on Agro Meteorological Indices of Wheat under Conditions of North-western Himalayas, India

Climate change in recent times have presented a scenario of elevated susceptibility of wheat to rising temperatures. Agro-meteorological indices can present a scenario of variable response of wheat to diverse conditions. A field investigation was conducted in rabi season of 2016-17 at Research farm, Department of Agronomy, CSK Himachal Pradesh Krishi Vishvavidyalaya, Palampur to evaluate the influence of sowing dates and wheat cultivars on agro-meteorological indices such as growing degree days, photothermal units, Helio thermal units and phenothermal index of wheat crop. The field investigation involved five sowing dates (15th October, 30th October, 15th November, 30th November and 15th December) and wheat cultivars (HPW-349 and HPW-155) which were studied in a factorial randomized block design with three replications. The results of the investigation revealed that timely sown crop i.e., on 15th October recorded the highest values for agro-meteorological indices for both the wheat cultivars such as growing degree days, Helio thermal units, photothermal units and phenothermal index across various wheat development stages such as complete emergence, crown root initiation, tillering, ear emergence and physiological maturity. Therefore, timely sowing of wheat by 15th October was concluded to be the best for optimized agro-meteorological indices such as growing degree days, photothermal units, Helio thermal units and phenothermal index under conditions of North-Western Himalayas.

Agrometeorological indices, physiological growth parameters and performance of finger millet as influenced by different cultivars under hot and sub humid region of Odisha

Present-day agriculture is under tremendous pressure due to various factors such as climate change, degradation of soil and water quality, and yield plateauing of major food crops. Under these scenarios, there is an urgent need to choose a climate-resilient and ecologically hardy crop which can perform under adverse conditions with low input requirements. In this regard, millets can be suitable crops for agricultural sustainability. Among various millets, finger millet (Eleusine coracana L. Gaertn) is cultivated mainly in India and Africa. However, most farmers grow finger millet with local cultivars, and improved ones can be replaced to enhance productivity. The present investigation conducted at the Post Graduate Research Farm of Centurion University of Technology and Management, Odisha, focused on evaluating suitable cultivars of finger millet. The study revealed that cultivars significantly influenced finger millet growth, productivity, and economics. The physiological growth parameters, namely, crop growth rate, relative growth rate, net assimilation rate and leaf area duration were significantly influenced by finger millet cultivars. The growing degree days (GDD), helio-thermal units (HTU) and photothermal units (PTU) of the finger millet showed a great variation among the cultivars. The Maximum total GDD (2169 °C day), HTU (18141 °C day hours) and PTU (24297 °C day hours) were recorded in the cultivar Hima(w) VR 936. The cultivars Indravathi VR 1101, Sri Chaitanya VR 847 (1.73) and Hima (W) VR 936 (1.60) were superior to other cultivars in expression of the grain yield and economics of finger millet. The study concluded that the cultivation of Indravathi and Sri Chaitanya could be considered as short-duration cultivars; however, Hima can be chosen as long duration crop for successful finger millet cultivation with higher net returns and benefit-cost ratio under hot and sub-humid regions of Odisha.

Influence of Diverse Growing Environments and Plant Densities on Phenological Development and Agrometeorological Indices of Groundnut (Arachis hypogaea L.) in the Hyper Arid Zone of Rajasthan, India

Groundnut (Arachis hypogaea L.) stands as a significant oilseed crop globally. The growth, development, and productivity of these plants are notably affected by the adverse impacts of global climate change. Therefore, the current study sought to examine how diverse growing environments and planting densities influence the phenological development of groundnut in the hyper-arid zone of Rajasthan, India. A field experiment spanning the kharif seasons of 2017, 2018, and 2019 was conducted at Krishi Vigyan Kendra, Swami Keshwanand Rajasthan Agricultural University, Bikaner, India. The experiment laid out in split-plot design with four replications. The treatments included three main plots for growing environments (sowing on May 15, May 30, and June 15) and three sub-plots for planting densities (1.67 lakh ha-1, 2.50 lakh ha-1 and 3.33 lakh ha-1).. The outcomes of the field experiment indicates that sowing groundnut on May 30 was statistically on par with sowing on June 15 and resulted in higher values of GDD, helio thermal units (HTU), PTI, heat use efficiency (HUE), photothermal use efficiency (PUE), and heliothermal use efficiency, as well as hygrothermal use efficiency (Hg TUE-I and II) at the initiation of flowers and peg formation stages. However, at later growth stages significantly higher values of GDD, HTU, HUE, PUE, HgTUE-I and II were observed with the May 15 sowing. These values gradually decreased with delayed sowing up to May 30 and June 15. Further, increasing the planting density from 1.67 lakh ha-1, 2.50 lakh ha-1 and 3.33 lakh ha-1 significantly enhanced the HTU, HUE, PUE, HgTUE-I and II at various phenological stages of groundnut. Therefore, these findings underscore the significance of precise timing and density control in maximizing groundnut yields under challenging environmental circumstances. By understanding and modifying these variables, farmers can mitigate the adverse effects of climate change and enhance groundnut productivity, especially in extremely arid areas like Rajasthan.

Effect of Sowing Dates and Seed Priming on Agrometeorological Indices and Soil Moisture Regimes of Chickpea in North Central Plateau Zone NCPZ of Odisha

Background: field experiment entitled “Effect of sowing dates and seed priming on agrometeorological indices and soil moisture regimes of Chickpea in NCPZ of Odisha” was conducted at RRTTS, Keonjhar, Odisha, during the Rabi season for two consecutive years i.e., 2021-22 and 2022-23. Method: The field experiment was laid out in factorial RBD design with three replications and two factors. There were 3 dates of sowing in Factor A (D1-25 November, D2-5 December, D3- 15 December) and 5 moisture conservation practices in Factor B (M1- Control, M2- Seed priming with water for 8 hours, M3- Osmopriming (Seed priming with CaCl2 solution @0.5% for 8 hours), M4- Straw mulch@ 5t/ha and M5- Straw mulch@ 5t/ha +Seed priming with CaCl2 solution @0.5% for 8 hours). Seed priming controls the hydration of seeds that helps in the pre germinative metabolic activity of the seeds. So even if the soil has less moisture that will not affect the uniform and proper germination of the seeds. All together there were 15 treatment combinations. The test crop variety taken was JAKI-9218. Among the three dates of sowing, D2 (5th Dec) sowing recorded the tallest plants (41.47 cm). but were recorded in D1 (25 Nov) sowing. Early sowing on 25th November recorded the maximum number of primary and secondary branches and required a greater number of days to 50% flowering (41.8 days) and days to physiological maturity (101.1 days). Results: Among the moisture conservation practices, M5 (Straw mulch@ 5 t/ha+Seed priming with CaCl2 solution @ 0.5% for 8 hours) recorded the tallest plants, maximum number of primary and secondary branches, maximum number of days taken to 50% flowering (40.7 days) and days taken to physiological maturity (100.1 days), maximum number of pods per plant (44) and number of seeds per pod (3.62), grain yield (1812 kg/ha) and straw yield (218 kg/ha). This treatment recorded the minimum consumptive use of water (203.5 mm) and rate of moisture use (1.36 mm/day) but the moisture use efficiency was maximum (12.34 kg/ha-mm). Treatment M5 recorded the maximum growing degree days (2182°C day), heliothermal unit (15077°C day hrs), photothermal unit (22595°C day hrs) and heat use efficiency (0.94 kg/ha/°C) to reach maturity. Chickpea when combined with suitable date of sowing and moisture conservation practices for proper utilization of carry-over residual soil moisture in the rice fallows gives higher yield.

Effect of Sowing Time Induced Weather Regimes on Growth and Yield of Chickpea under Irrigated Condition

A field experiment conducted to study the effect to find out optimum time of sowing and suitable cultivar for sustainable chickpea production in the region. The study was undertaken to find yield variation with extended sowing date. Five different sowing dates viz., 30th October (44 MW), 15th November (46 MW), 30th November (48 MW), 15th December (50 MW) and 30th December (52 MW) with two chickpea cultivars viz., JAKI 9218 and Vijay were studied. The varieties selected dominated chickpea cultivation in the region. The results revealed that crop sown on 30th October produced higher but statistically equivalent number of pods/plant, number of seeds/plant and grain yield as compared to 15th November sowing. Crop sown on 30th October accumulated higher Growing Degree Days (GDD: 2012 day0C) and Heliothermal Units (HTU: 13515 0C day hr) closely followed by 15th November sown crop (GDD; 1975-day 0C, HTU: 13130 0C day hr) during cropping period from vegetative to pod-seed development phase. The number of pods/plant, weight of seed/plant and test weight was higher in cultivar JAKI 9218 than Vijay. Maximum GDD (1888 0C day) and HTU (12706 0C day hr) were accumulated by cultivar JAKI 9218 closely followed by Vijay (GDD: 1856 0C day; HTU: 12449 0C day hr).

Agro-Climatic Indices, Plant Growth and Yield of Bt Cotton as Influenced by Planting Time and Spacing

A field experiment was conducted in kharif season 2020 to study the effect of sowing time and row spacing on growth, yield and agro-climatic indices of Cotton at Research Farm, Department of Agricultural Meteorology, CCS Haryana Agricultural University, Hisar. The experiment was performed in split-plot design and replicated thrice. The experiment included nine treatment combinations with three sowing dates and row spacings. Among different sowing times, cotton sown on 19th April had significantly higher plant height (176.3 cm), dry matter accumulation (453.39 g plant-1), LAI (1.92), GDD (Growing Degree Days), HTU (Heliothermal Units), PTU (Photothermal Units) and seed cotton yield (3057 kg ha-1) in comparison to sowing in May i.e. May 8th and May 28th. Among various row spacings, cotton planted with a row spacing of 67.5 cm x 60 cm produced significantly higher seed cotton (2657 kg ha-1) and plant height (156.40 cm), although growth parameters i.e. LAI (2.26) and dry matter accumulation (397.92 g plant-1) alongwith Agro-climatic indices (GDD, HTU, PTU) were observed to be greater with a row spacing of 100 x 60 cm.

Agroclimatic Indices, Phenology and Growth Response of Clusterbean to Different Dates of Sowing and Varieties

A field experiment was performed to study the effect of different sowing times and varieties on agroclimatic indices, phenology and growth of clusterbean at CCS Haryana Agricultural University, Hisar (Haryana). Experiment was laid out in factorial randomized block design with three replications. Treatments consists of two factors i.e. sowing time and varieties. Three clusterbean varieties i.e. HG 365 (V1), HG 563 (V2) and HG 2-20 (V3) with each sown at three different dates of sowing i.e first (D1), third (D2) and fourth (D3) week of July. Clusterbean variety HG 563(V2), sown in first week of July (D1) resulted in significantly higher accumulation of agroclimatic indices i.e. growing degree days, photo thermal units, heliothermal units and heat use efficiency because the early sown crop had a fully developed normal reproductive phase and took longer time to attain maturity. Similarly, more number of days were taken for emergence, days to 50% flowering, days to 50% pod formation and days to maturity in variety HG 563, sown in first week of July. Significantly higher leaf area index and dry matter accumulation were observed in HG 563 sown on 1st week of July than rest of the varieties and date of sowings.

Utilization of thermal indices for production of nutri-cereals in non-traditional areas of Bihar

An experiment was conducted during summer seasons of 2017 and 2018 on clay-loam soil of the ICAR-Research Complex for Eastern Region, Patna, Bihar, to study the performance of different nutri-cereals and their heat-unit requirements to complete their phenological cycles. Significantly higher grain yield, i.e. 1.92, 1.76 and 1.53 t/ha, was achieved in barnyard millet (Echinochloa esculenta (A. Braun) H. Scholz) followed by sorghum [Sorghum bicolor (L.) Moench] and pearl millet [Pennisetum glaucum (L.) R. Br.], respectively. Whereas the higher straw and biological yields were observed in sorghum (8.91 and 10.8 t/ha), pearl millet (7.14 and 8.67 t/ha) and little millet (Panicum sumatrense Roth ex Roem. & Schult.) (5.50 and 6.67 t/ha). Barnyard millet also showed the maximum crop productivity (24 kg/ha/day). Remarkably higher biomass productivity was noted in sorghum (114.7 kg/ha/day), followed by pearl millet and little millet (96.3 and 85.5 kg/ha/day). Pearl millet (702.9°C-day) accumulated the minimum growing degree-days (GDD) to attain 50% flowering. Further, pearl millet (4,111. 4°C day-hr) being at par with proso-millet (Panicum miliaceum L.) (4,280.3°C day-hr) and little millet (4,295.7°C day hr) attained significantly lower heliothermal units (HTU) to reach 50% flowering. Barnyard millet (1.25 kg/ha °C-day), followed by sorghum and pearl millet (1.01 and 0.91 kg/ha °C-day) acquired considerably higher HUE for grain production. Sorghum (6.11 kg/ha °C-day) followed by pearl millet (5.17 kg/ha °C-day) and little millet (4.48 kg/ha °Cday) captured significantly maximum HUE for biomass production. Our results indicated that, cultivation of nutri-cereals such as barnyard millet, sorghum, pearl millet and little millet is a viable option to utilize the fallow period (summer season) for achieving the nutritional security and realizing the livelihood improvement in this region.

Effect of Weather Indices under Different Sowing Windows on Grain Yield of Sorghum

Background: Sorghum (Sorghum bicolor L. Moench) is one of the major staple cereal crops after rice and wheat. Photoperiod (day length) sensitivity has been shown to affect the duration of plant’s vegetative phase based on sowing dates. Optimum sowing date is one of the most important factors that play an important part in yield. Methods: A field experiment was carried out during the summer season of 2022. in the Eastern block farm (37F) of Tamil Nadu Agricultural University, Coimbatore in sandy loam soil to study the phenological behaviour of sorghum as influenced by sowing window (D1 - First fortnight of February, D2 - First fortnight of march and D3 - First fortnight of April) by analysing the Helio-thermal units (HTU), Photo-thermal units (PTU) and growing degree days (GDD) and to evaluate the performance of sorghum CO-32 cultivar. The experiment was laid out in strip plot design. Results: Among the different sowing windows highest grain yield was recorded when sowing was done in I FN of April (2602.81 kg/ha) followed by I FN of March (2484.53kg/ha). The attainment of phenophases was found early in February sowing. It was observed that accumulated heat units increased by 114 °C and 142.2 °C days in March and April sown crop compared to February sown crop. Among the sowing windows maximum photo thermal units were accumulated by April sown crop (15135.2oC day hrs) followed by March (13485.57oC day hrs) and February (11608.5oC day hrs) sown crop respectively.

Estimation of yield, phenology and agro-meteorological indices of Quality Protein Maize (Zea mays L.) under different nutrient omissions in temperate ecology of Kashmir

The major yield governing factors especially under rainfed ecosystem are the agro-meteorological indices. Hence, an experiment was conducted in 2021 kharif season to examine the impact of nutrient omission on phenology, yield and agro-meteorological indices of Quality Protein Maize (QPM) under the North Western Himalayas of India at the Agronomy farm of FoA (Faculty of Agriculture), Wadoora, Sopore, SKUAST-Kashmir. Eight treatments were used in the experiment viz. (T1-Absolute control, T2-N120P75K40, T3-N120P75K40Zn5S10, T4-P75K40Zn5S10 (-N), T5-N120K40Zn5S10 (-P), T6-N120P75Zn5S10 (-K), T7-N120P75K40S10 (-Zn) and T8-N120P75K40Zn5 (-S)), using a randomized complete block design with three replications. Results demonstrated that recommended dose of fertilizer plus zinc and sulphur (T3-N120P75K40Zn5S10) noted higher grain (9.78 t ha−1) and biological (22.05 t ha−1) yield, a longer period of time to reach various phonological stages thereby achieved maximum heat units or growing degree days (GDD), heliothermal units (HTU), photo-thermal units (PTU), pheno-thermal index (PTI) and heat use efficiency (HUE). Nitrogen was the most limiting nutrient thereby accumulating least heat units and HUE. The agrometeorological indices could be therefore helpful in predicting the phenology and maize yield. The outcomes of the experiment showed that using the recommended fertilizer dosage plus zinc and sulphur in QPM should be adopted to attain higher yield under the North Western Himalayas of India, However, additional agro-ecological study is required to further validate the findings.

Effects of sowing dates on phenology, radiation interception and yield of wheat

An experiment was conducted during rabi seasons of 2015-16 and 2016-17 to study the phenology, accumulation of growing degree days (GDD), helio-thermal unit (HTU), photo-thermal unit (PTU), Heat use efficiency (HUE), Radiation use efficiency (RUE)and to assess the effects of thermal and radiation regimes on wheat at research farm of Department of Agricultural Meteorology, Chaudhary Charan Singh Haryana Agricultural University, Hisar during rabi seasons of 2015-16 and 2016-17. The twenty-seven treatment combinations were tested in split plot design with three replications. The main plot treatments consist of three date of sowing, i.e., D1- 2nd fortnight of November, D2- 1st fortnight of December, D3- 2nd fortnight of December and sub plot treatments consist of three varieties, i.e., V1- WH 1105, V2- DPW 621-50 and V3- HD 2967. Daily meteorological data recorded at Agromet observatory near the experimental plot was used for computation of agrometerological indices, i.e., heat unit (HU), heliothermal unit (HTU), photothermal unit (PTU), heat use efficiency (HUE) and radiation use efficiency (RUE).

Production potential, quality and thermal utilization of fodder pearl millet varieties under different sowing environments in irrigated conditions of central Punjab in India

An experiment was conducted at Punjab Agricultural University, Ludhiana, India during two consecutive years i.e., 2019 and 2020 to study the effect of dates of sowing and pearl millet varieties on productivity and quality of green fodder and thermal utilization by the crop. The field experiment was laid-out in a split plot design with seven dates of sowing (1st April, 15th April, 1st May, 1st June, 15th June, 1st July and 15th July) in main plots and two varieties of pearl millet (PCB 165 and FBC 16) in sub plots with three replicates. Significantly highest green fodder yield (69.3 t/ha) was obtained with 1st June sowing which was probably on account of maximum plant height and number of tillers. The 1st June sown crop also recorded significantly highest dry matter and crude protein yield of 15.0 t/ha and 0.95 t/ha, respectively. Both advanced and delayed sowings recorded significant reduction in green fodder and dry matter yield. The crop sown on 1st May required maximum growing degree days, photo-thermal and helio thermal units at 50% flowering stage and sowing done early as well as late recorded significant reduction in these agro-climatic indices. Across different dates of sowing, PCB 165 registered an increase of 11.9 and 12.4% in green fodder and dry matter yields, respectively over FBC 16 due to higher accumulation of growing degree days, photo-thermal and helio thermal units for 50% flowering stage. The interaction effect showed that PCB 165 sown on 1st May, 1st and 15th June recorded significantly more green fodder yield over FBC 16, while the differences were narrow and non-significant at other dates of sowing.

Effect of Soil Types on Phenology and Heat Units of Quinoa

Background: Quinoa, a promising pseudocereal crop has superior nutritional profile and able to withstand wide range of biotic and abiotic stresses. Understanding the effect of different soil types on phenology and heat units is important in new crop like quinoa. Therefore, in this investigation, different soil types that widely dispersed around Coimbatore were used to evaluate the performance of quinoa on its phenology and further heat units. Methods: Pot experiment was carried out in the Department of Agronomy, Tamil Nadu Agricultural University, Coimbatore during Kharif 2022 season. Eight soil types were collected from different areas around Coimbatore and tested in completely randomized design with three replications. Development of phonological stages were noted and in turn calculated heat units by using standard formulae. Result: Results of the investigation revealed that clay loam textured Ooty soils took maximum days to attain four phenological stages, viz., branching, panicle initiation, flowering and physiological maturity of quinoa than other soils. Similarly, more heat units (Growing Degree Days, Helio Thermal Units, Photo Thermal Units and Relative Temperature Disparity) were recorded with the soils collected from Ooty when compared to other soils. Sandy loam soils of Mettupalayam registered the least number of days to attain different developmental stages and also recorded the lowest heat units of quinoa. Based on the above results, it can be concluded that among eight different soils, the growth of quinoa was prolonged in clay loam textured Ooty soils and correlation with yield indicated that extending duration enhanced the yield.

Crop weather relationship in oilseed rape (Brassica napus) for north-west foothills of Himalayas, India

Agrometeorological indices have a strong correlation with growth, yield attributes and yield of crop and can be effectively used to select suitable cultivar for specific environmental conditions. Therefore, to study the cumulative effect of weather variables in terms of agrometeorological indices on cultivars of oilseed rape (Brassica napus L.) sown under different sowing environments, field experiments were conducted at the research farm of Agrometeorology section, Sher-e-Kashmir University of Agricultural Sciences and Technology, Jammu, Jammu and Kashmir during winter (rabi) season of 2018–19 and 2019–20. The treatments were comprised of 3 sowing environments, viz. 42nd SMW (standard meteorological week), 44th SMW and 46th SMW along with 3 cultivars (GSL-1, ONK-1 and DGS-1) of oilseed rape in factorial randomized block design with 3 replications. The pooled data of 2 years revealed that allthe cultivars of oilseed rape sown in 42nd SMW accumulated higher growing degree days (GDD), photothermal units (PTU) and heliothermal units (HTU) with higher rate of dry matter accumulation in comparison to 44th SMW and 46th SMW sown crop. The agrometeorological indices, viz. GDD, PTU and HTU were significantly positively correlated with growth parameters, yield attributes and yield at vegetative stage, while, PTU and HTU were negatively correlated at reproductive stage of the crop. Due to the significant impact of weather variables, the seed yield of all the oilseed rape cultivars decreased when the sowing was delayed from 42nd SMW to 46th SMW during both the years. Among cultivars, GSL-1 recorded significantly higher seed yield followed by ONK-1 and DGS-1.

Evaluating the seasonal accumulation of Heat units as an agroclimatic indicator on Baby corn (Zea mays L.) under different sowing windows

Temperature determines the plant's growth and development, which decides the onset of different phenophasic stages of the Baby corn. This study aimed to evaluate the phenological behaviour and yield of Baby corn (Zea mays L.) influenced by sowing windows and heat units with the field investigations carried out during winter (January – April) and kharif (June – September) 2022 at Eastern Block Farm of Tamil Nadu Agricultural University, Coimbatore. Growing Degree Days (GDD), Photo Thermal Units (PTU), Helio Thermal Units (HTU), Relative Temperature Disparity (RTD), Heat Unit Efficiency (HUE) and seasonal efficiency were calculated at different phenological stages. The results revealed that early attainment of phenophases was noticed during winter (62.5 days - January 21st to 27th April) than kharif (77.1 days – 15th June to 4th October). Among seasons, higher accumulation of GDD (1553) and PTU (19099) was observed during kharif 2022, whereas maximum accumulation of HTU (9923) and RTD (2146) was observed in winter 2022. Seasonal efficiency was higher during kharif (118) than during the winter season (81). The sowing windows significantly influenced the higher accumulation of heat units and yield attributes. Hence, higher yield (11922.7 kg ha-1) and HUE (7.3) were obtained during kharif than in winter 2022 (yield – 7849 kg ha-1 and HUE – 5.8). Weather parameters showed a negative correlation except RH-I, WS, SR and HUE during winter 2022 (R2=0.802) and RH-II, WS, RF, Daylength, HUE during kharif 2022, which had a positive correlation (R2=0.795). Baby corn is highly sensitive to increasing temperature. Hence, the study expresses the effect of varying ambient temperature on the duration between the phenological stages and yield.

Thermal Requirement, Heat and Radiation Use Efficiency of Kharif Soybean in Middle Gujarat Region as Influenced by Cultivars and Plant Geometry

The present study proposes to measure the thermal requirements, heat and radiation use efficiency of kharif soybean cultivars (NRC 37, GS 1 and GS 2) in the central region of Gujarat. The findings of study conclude that among all the different geometry 30 x 10 cm produced highest seed (4403 kg/ha) and total biomass yield (5818 kg/ha) over the other two spacing because higher heat use efficiency (heat use efficiency (HUE) for Growing degree day (GDD)- 0.69 kg/ha/°C Day; HUE for Heliothermal units (HTU) - 0.14 kg/ha/°C Day hour; HUE for Photothermal units (PTU) - 0.05 kg/ha/°C Day hour). The cultivar NRC 37 (4415 kg/ha) produced highest seed yield followed by GS 1 (3799 kg/ha) and GS 2 (3670 kg/ha). Heat unit requirement of cultivar NRC 37 (GDD - 1952°C Day; HTU – 9894°C Day hour; PTU-25974°C day hour) was more as compared to GS 2 (GDD - 1951°C day; HTU – 9893°C day hour; PTU-25973°C day hour) and GS 1 (GDD - 1931°C day; HTU – 9809°C day hour; PTU-25681°C day hour), respectively. The radiation use efficiency (RUE) for seed yield and biomass are more in 45 x 5 cm geometry.

Chickpea Phenology and Yield Related to Agrometeorological Indices Under Different Temperature Regimes

Agrometeorological variables have a major impact on crop development and yield, known as crop phenology. The phenology of chickpea under various thermal regimes was evaluated in a field experiment during the rabi season of 2019–2020 at Ishwardi, Pabna district of Bangladesh. Three chickpea cultivars (V1 = BARI Chola 5, V2 = BARI Chola 10, and V3 = BARI Chola 11) were planted under irrigation in four temperature regimes (D1 = November 5, D2 = November 20, D3 = December 5, and D4 = December 20). Early sowing on November 5 had a larger growing degree day (GDD), 2135.5 C days from sowing to harvest, and later sowing on December 20 had a lower GDD (1743.4 C days). From planting to harvest, V1 required a greater GDD (1971.5C days) while V3 required a lower GDD (1805.8 C days). Average heliothermal unit (HTU) varied from 11764.07 C day hrs (D4) to 13879.4 C day hrs (D1). Variety V1 required 13757.85°C day hrs HTU, while V2 and V3 required 13347.05°C day hrs and 11636.8 °C day hrs, respectively. The number of days needed from planting to harvest under D1, D2, D3, and D4 growing conditions were 136.3, 122.6, 118.6, and 107.4 days, respectively. Growth and yield were better for V1 and V2 under D1 settings, but they were lower under D3 conditions, while V3 was better under D2 conditions. BARI Chola 11 among the genotypes was harvested much more quickly and produced more effectively in late-sowing conditions. Physiological maturity and grain yield can be predicted with 92% and 99% accuracy, respectively, using cumulative GDD and HTU. Therefore, the study recommended that different thermal conditions and cultivars' reactions to heat utilization and economic yield have a substantial impact on chickpea cultivar yields.

Impact of Heat Units on the Phenology and Yield of Baby Corn (Zea mays L.) in Western Agro Climate Zone of Tamil Nadu

Field investigation was carried out during winter 2022 at Tamil Nadu Agricultural University, Coimbatore to study the phenological behaviour and yield of baby corn (Zea mays L.) as influenced by heat units. The split-plot design consisting of three dates of sowing viz., D1 – 21st January, D2 – 5th February and D3 – 20th February as a main plot and three spacing viz., 60x45 cm (S1), 60x30 cm (S2) and 60x20 (S3) as a sub plot was adopted and replicated thrice. Growing Degree Days, Helio Thermal Unit and Heat Use Efficiency were calculated for different phenological stages viz., plant emergence to 50% flowering (P1), 50% flowering to cob emergence (P2), cob emergence to harvest (P3), plant emergence to cob emergence (P4), 50% flowering to harvest (P5) and plant emergence to harvest (P6). The results revealed that sowing on 20th Feb. had completed the phenophases early, followed by 5th Feb and 21st Jan. GDD required for attaining physiological maturity was highest in 20th Feb. (1194.6 ºC days)). Except morning relative humidity, wind speed and solar radiation, all other weather parameters had negative correlation with baby corn yield (R2=0.921). The optimum temperature was obtained during D1 (27.2 – 27.5 ºC) along with short-day length (11.7 hours) resulting in higher corn yield (9333.3 kg/ha) as well as higher HUE (5.75).

Phenology and Heat Unit Requirement of Wheat Varieties under Different Thermal Environments and IW: CPE Ratio-Based Irrigation Scheduling

A field experiment was conducted during rabi seasons of 2020-21 and 2021-2022 to study the heat unit indices viz; accumulated growing degree days (GDD), helio-thermal unit (HTU), photo-thermal unit (PTU), phenothermal index, helio-thermal use efficiency (HTUE), photothermal use efficiency (PTUE) and heat use efficiencies (HUE) at different phenological stages of two wheat (Triticum aestivum L.) varieties (Lok 1 and MP 3336) grown under different thermal environments (3rd December, 18th December and 2nd January) and irrigation schedules (IW: CPE= 1.0, IW: CPE= 0.9, IW: CPE= 0.8 and IW: CPE= 0.7). Results of present study reveals that the crop sown on thermal environment of 3rd December took maximum duration (113), GDD (1595.7°C days), HTU (11,146.3°C days hours), PTU (16,628.6°C days hours), HUE (2.97 kg ha-1°C-1 day), HTUE (0.43 kg ha-1°C-1 day), and PTUE (0.28 kg ha-1°C-1 day). Among irrigation schedule I1 (IW: CPE= 1.0) attained maximum crop duration (103 days), GDD (1513.8°C days), HTU (10,550.0°C days hours), PTU (15,461.3°C days hours), HUE (2.96 kg ha-1°C-1 day), HTUE (0.43 kg ha-1°C-1 day) and PTUE (0.29 kg ha-1°C-1 day). As regards varieties, MP 3336 took maximum duration (104), GDD (1548.1°C days), HTU (10818.9°C days hours), PTU (15863.5°C days hours), HUE (2.84 kg ha-1°C-1 day), HTUE (0.41 kg ha-1°C-1 day) and PTUE (0.28 kg ha-1°C-1 day). The heat unit indices decrease during vegetative stages but increases during reproductive phase. The crop duration, heat indices (GDD, HTU, PTU and PTI), HUE, HTUE, PTUE and grain yield was higher under thermal environment of 3rd December sown crop with irrigation schedule I1 (IW: CPE= 1.0) and wheat variety MP 3336.

Leaf Color Chart (LCC)-Based Precision Nitrogen Management for Assessing Phenology, Agrometeorological Indices and Sustainable Yield of Hybrid Maize Genotypes under Temperate Climate

Excessive nitrogenous fertilization in years resulted in larger nitrogen and profit losses. This problem can be reduced by using need-based and time-specific nitrogen management. Therefore, a field experiment was carried out during the Kharif season of 2019 and 2020 in order to evaluate the impact of precision nitrogen management on the phenology, yield and agrometeorological indices of hybrid maize genotypes at the Agronomy Research Farm, FoA Wadura, Sopore, SKUAST-Kashmir. The experiment was carried out in split-plot design consisting of maize hybrids (Shalimar Maize Hybrid-2 Vivek-45 and Kanchan-517) as main plot treatments and precision nitrogen management (T1: Control, T2: Recommended N, T3: 25% N as basal ≤ LCC 3@20 kg N ha−1, T4: 25% N as basal ≤ LCC 3@30 kg N ha−1, T5: 25% N as basal ≤ LCC 4@20 kg N ha−1, T6: 25% N as basal ≤ LCC 4@30 kg N ha−1, T7: 25% N as basal ≤ LCC 5@20 kg N ha−1 and T8: 25% N as basal ≤ LCC 5@30 kg N ha−1) as sub-plot treatments. Results demonstrated that maize hybrids showed a non-significant difference in attaining different phenophases during both years. However, Shalimar Maize Hybrid-2 demonstrated higher grain (62.35 and 60.65 q ha−1) and biological yield (170.26 and 165.86 q ha−1), a higher number of days to attain different phenological stages in comparison to Vivek-45 and Kanchan-517 thereby achieved higher heat units, PTUs, HTUs, PTI. The application of nitrogen through LCC ≤ 5@30 kg N ha−1 noted higher grain yield (61.27 and 59.13 q ha−1) and biological yield (171.30 and 166.13 q ha−1) during 2019 and 2020 respectively. Higher values of Growing degree days (GDD), Heliothermal units (HTU), Photothermal units (PTU), Phenothermal index (PTI), heat use efficiency (HUE) and radiation use efficiency (RUE) were observed in the application of nitrogen through LCC ≤ 5@30 kg N ha−1 and required the highest number of days to reach different phenophases than other treatments during crop growing seasons of 2019 and 2020. The results demonstrated that Nitrogen application based on LCC ≤ 5@30 proved effective and should be adopted in maize hybrids especially in Shalimar Maize Hybrid-2 to attain higher yield under the temperate climate of Kashmir Valley.