Climatic change and wheat yield in semi ARID region of Punjab-India
R. Chaurasia, P K Sharma
Punjab Remote Sensing Centre, Ludhiana-141 004,India
G S Mahi, Gurmit Singh
Department of Agrometeorology
Punjab Agricultural University, Ludhiana-141 004,India
Abstract
An attempt has been made to study the effect of changing climatological parameters during the grain formation period of wheat on its yield in semi arid region of Punjab. Climatological data in respect of maximum and minimum temperature, relative humidity and sunshine for the months from December to April of three decades (1961-70, 1971-80 and 1981-90) was analyzed. The analysis of the data revealed that temperature during the month of March has pronounced effect on wheat yield, whereas pre-anthesis temperature has limited effect. It has been observed that maximum temperature during March contributes negatively to the yield while temperature positively. The maximum and minimum temperature around 26° and 12°C respectively during grain formation period results highest yield of wheat in the region. Positive or negative departure in temperature by 1°C from these optimum values causes reduction in yield by about 0.2 tones per hectares. A regression analysis between maximum and minimum temperature, relative humidity, sunshine and rainfall versus yield has been worked out with gave coefficient of correlation greater than 0.8.
Introduction
The variation in yield of agricultural crops is largely due to the changes in the climatic parameters during its growing period. Among all the climatological parameters temperature plays an important role during the vegetative growth and grain formation of the wheat crop (Marcellous et. al., 1972 : Wardlaw et al., 1980; Rawson, 1986). It has been reported that an average temperature of 15°C during grain formation is nearly optimum for maximum grain weight. (Chowdhury and Wardlaw, 1978; Weigand and Ceullar, 1981; and Fischer, 1985). The deviation in maximum and minimum temperatures above or below optimum value are found to influence the plant activities in many ways, the cumulative effects of which are observed in yield. Grain number and weight are reduced due to prolonged high temperature and drought conditions (Saini et al 1982; McDonald et al., 1983; Wardlaw, 1989; Nicolas et. Al., 1984. On the other hand prolonged lower temperature enhanced grain formation period resulting in higher grain weight.
Most of these studies have been conducted under laboratory conditions and their applicability needs be tested under field conditions. In the present paper attempt has been made to establish the relationship of wheat yield with the climatological parameters in semi-arid region of Punjab.
Study Area
The semi arid region of the Punjab is located in central part of the state and extends from the south-east to north-west. Ludhiana district situated in the central part of the this region having
sufficiently long record of different climatological parameters has been selected for this study .
Physical Resources of the region
Soil climate and water
The soils of the area are medium to light textured consisting variable amount of silt and clay. Temperature in the region fluctuates between 6° to 41°C. The average annual rainfall is about 700mm. The optimum climatic conditions for the wheat cultivation are observed during November to April. During this period day and night temperatures remain in the range of 20° - 30°C and 6° - 18°C respectively. In the growing season, occasional rainfall due to western disturbances amounts to 126mm and evaporation 650mm. solar radiation available to the crop is of the order of 2570 Mjm-2. Water in the region is of good quality and water table varies between 5 to 10 metres. In the flood plains, ground water contains Fe and F at some places.
Irrigation and Fertilizers
The intensive irrigation system increased the wheat irrigated are from 82 per cent in 1965-66 to 100 percent in 1979-80. It shows that whole of the wheat in the district is grown under assured irrigation system. The use of total NPK for wheat in the area is increasing fast with the adoption of the improved varieties. In increased from 328 kg per ha in 1980-81 to 527 kg in 1987-88 (fig. 1).
Fig 1 Wheat yield and fertilizer consumption in semi arid region of Punjab
