Environmental Science
AgriculturalAndFoodSciences,1970-2015-Agricultural And Food Sciences-2014.jsonl.gz.gz
Agricultural And Food Sciences Environmental Science
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Effect of temperature variations on growth, dry matter and yield of wheat (Triticum aestivum L) under Mid Himalayan Region of Uttarakhand.

Uttarakhand is composed, in parts, of the Himalayan mountain ranges having different altitudes and orientations. Wintertime eastward-moving low-pressure synoptic weather systems (western disturbances) are modified by these orographic barriers. Therefore, advance and proper information of maximum and minimum temperature becomes important for assessing natural hazard threats. The trend analysis for both maximum and minimum temperature using 2-year moving averages was done for the period 2003-2012. It shows moving average trends indicate that maximum temperature is decreasing over the period, while little increasing trend was observed in case of minimum temperature during the period 2003-2012. The experiment was conducted in a two factors randomized block design (RBD) with four replications, three dates of sowing and two varieties viz. UP – 1109 and Sonalika (RR-21) recommended for different sowing environments. Seasonal trends of maximum temperature indicate decreasing trend throughout the year, while minimum temperature shows decreasing trend during rainy season whereas during other three seasons the trend was reverse. The maximum temperature during winter seasons was increasing during the first and last pentad. In general the maximum temperature has shown increasing trend during the last pentad in all the four seasons. Temperature play very important role in flowering and maturity of crops as well as quality parameters also. Due to increasing temperature at the time of vegetative stages, early flowering and maturity has been observed in wheat.


Introduction
Over the hilly areas of the western Himalayas, such as Jammu and Kashmir, Laddakh, Himachal Pradesh and Uttarakhand, knowledge of maximum and minimum temperatures during the winter months is very important for assessing human comfort, cold weather conditions, avalanche release, state of snow and frost. Maximum and minimum temperatures at a specific location depend upon the season, synoptic conditions and local parameters, including orography, land-use and vegetation cover. It is difficult to predict locationspecific surface weather elements over complex mountainous regions by state-of-the-art numerical weather prediction (NWP) models, so statistical relationships are developed between a variable, which is to be predicted at the location of interest (predictand) and nearby observed values of surface and upper-air weather elements (predictors).
Uttarakhand state has varied topographical features ranging from high hills to Tarai thereby the state experiences different climatic conditions. The plains and valleys are hotter in summers as compared to hills. The valleys are cooler in winters. The region has wide variations in topography as well as weather. Agriculture is mainly rainfed. Major problems are low temperature, erratic distribution of rainfall and short growing season. The major crops of the region are small millets, under-utilized crops like amaranth, rice bean, buck wheat etc. Irrigated rice is grown predominantly in valleys and upland rice is cultivated at higher elevations. The mid hill regions of the state supports off season vegetable crops (Murty et al. 2002). The temperatures fall rapidly during October and drops down to subzero temperature during winter in the region. The fall in temperature greatly influences the crop growth and agricultural production. In mid Himalayan region during grain filling stage of amaranth, even 1°C drop in minimum temperature in October, drastic yield reduction was observed (Murty and Singh, 2002).

Environment Conservation Journal
The diurnal temperature variations in the region are small therefore, temperature plays and important role in crop production. Hence an attempt is made to study the temperature variation in mid Himalayas region. Such studies have attempted by different authors in different parts of the India (Pant and Hingane, 1988Jain and Dubey, 1991, Samui and Gupta, 1992, Attri et al. 1995.

Material and Methods
The daily meteorological data of Ranichauri (longitude of 78 0 02' E, (latitude of 30 0 15, N and an altitude of 1950 m msl) in mid Himalayan region of Uttarakhand for the period 2003-2012 was utilized for the study. The daily maximum and minimum temperatures were converted to monthly, seasonal and yearly average for statistical analysis. The temperature trends were determined using 2year moving averages. The soil moisture percentage measured at periodic interval of 15 days during the crop season .The growing degree days (GDD) and actual evapotranspiration (AEt) values derived from Thornthwaite method during different Phenological stages of crop growth and their dates of occurrence. The total dry matter (g/ m 2 ) and plant height (cm) were recorded at various growth stages of crop. The yield and yield contributing characters viz, 1000 seed weight, number of plants/m 2 , number of spikelet/panicle were recorded at the time of harvesting.

Results and Discussion
The trend and moving average of both maximum and minimum temperatures were calculated and the results are as follows: The maximum and minimum temperature trends are presented in Table 1. The trend of minimum temperature from 2003-2012 indicates very little increasing trend while the moving average trends show slight decline in temperatures. Similar results were reported by Ram sing (2003). He was observed that in maximum number of months the minimum temperature departure was near normal followed by decrease in minimum temperature at Hisar. The maximum temperature ( Fig.1) trend was decreased over the period of study. Compared to the minimum temperature the deviation of maximum temperature was decreased over the period of study. Compared to the minimum temperature the deviation of maximum temperature was less. The data is almost following the trend line. The trend line equations are presented in Fig.1. The seasonal analysis indicates that the minimum temperature shows an increasing trend during, winter and post monsoon seasons while a sharp decline was observed during summer season. The temperature variation was more in rainy season and less in post rainy season. The standard deviation (SD) and Mean of maximum and minimum temperatures are presented in Table 2 Similarly, the number of grains/m 2 varied between 5242 and 7162. The 1000 seed weight was around 40.00 g across varieties and dates of sowing.The seed yield as influenced by different dates of sowing and varieties is presented in table 7. The highest seed yield of 1782.48 kg/ha was recorded with second date of sowing. Across dates of sowing, variety UP-1109 produced 1782.48 kg/ha while variety Sonalika produced 1489.55 kg/ha.

) during different growth stages of crop
The significant difference in seed yield was observed due to different dates of sowing, the first date of sowing produced highest yield in case of UP-1109 while, Sonalika produce the highest yield in second date of sowing. Though, the yields due to varieties and interaction between dates & varieties were not significant. The performance of wheat during rabi season 2012-13 was found to be satisfactory with second and second dates of sowing only due to even distribution of rainfall during the crop season, even then the amount of rainfall was below normal the requirement of the crop/normal rainfall throughout the season.   Therefore, early and normal sowing of wheat crop is recommended under rainfed condition in mid Himalayan region. Late sowing of the crop is not recommended since it germinates late on receipt of rainfall followed by low temperature in Jan & Feb months and also low rainfall in March/April month coincides with peak growth period of the crop. Early, normal and late sown crops in the Kharif season germinated well and thereafter the crops suffered slightly due to the excess moisture and high humidity prevailed in the region throughout the season due to the excess rainfall from July and August months coincides with grand growth stage. Thereafter seed setting stage of the most of the kharif crops, resulting into the performance of the kharif crops were not good and production below normal yields especially in underutilized crops. The performance of Rabi crops (2012-13) was in general not satisfactory due to dry condition attributed by low rainfall during Rabi season. However, the crops suffered from moisture stress during the terminal stages of the crop. The overall performance of rabi crops was satisfactory due to optimum temperature for proper growth, development, flowering, maturity and yield of wheat. From the above studies it can be concluded that the maximum temperature as shown decreasing trend while the minimum temperature is almost stable during the period of study at College of Forestry & Hill Agriculture, Ranichauri. The seasonal variation of minimum temperature has indicated that the trends are increasing in all the seasons except rainy season.