Showing papers in "Journal of Agrometeorology in 2009"

Sensitivity of Penman-Monteith estimates of reference evapotranspiration to errors in input climatic data.

Abstract: The Penman-Monteith (P-M) equation with its new definition of reference crop evapotranspiration (ET0) is recommended by FAO as the standard method of crop water requirement calculation, and also to compare other methods The ET0 component of the CROPWAT model, which is based on the P-M equation, was examined for sensitivity to errors in input data under the environment of a semi-humid sub-tropic region of Bangladesh The results showed that the ET0 estimates are most sensitive to maximum temperature and least sensitive to minimum temperature The order of sensitivity noticed is: maximum temperature > relative humidity > sunshine duration > wind speed > minimum temperature The sensitivity coefficients showed seasonal variation The model parameter ‘Angstrom’s coefficients’ showed sensitivity to errors in single or pair values The implications of sensitivity to ET0 estimates and in selecting appropriate method for ET0 estimation in a data-short environment are discussed

Response of wheat crop to different thermal regimes under the agroclimatic conditions of Jharkhand.

Abstract: Temperature is an important environmental factor that affects plant development, growth and yield. Changes in seasonal temperature affect the grain yield mainly through bringing changes in phenological development processes. Winter Crops are especially vulnerable to high temperature during reproductive stages and differential response of temperature change (rise) to various crops has been noticed under different production environments (Kalra et al 2008). Hundal (2004) observed that a 2 oC increase in temperature in wheat or rice resulted in 15-17 percent decrease in grain yield of both crops but beyond that the decrease was very high in wheat. Next to paddy and maize, wheat is the most important staple cereal for Jharkhand state which occupies an area of 4% of total cropped area. Jharkhand comes under the agro-climatic region of Eastern plateau and Hills. Since rainfall in this region is relatively high with an average annual rainfall of 1398.8 mm, wheat cultivation in Jharkhand has gained popularity in recent years and area under this crop is gradually expanding with the adoption of rainwater harvesting and re-uses technique for assured irrigation. Cool weather during vegetative period and warm weather during maturity are ideal requirements for wheat (Mavi, 1986).

Agro-topo climatological studies for crop planning - a case study for the northen hills agroclimatic zone of Chhattisgarh state.

Abstract: In the Northern Hills agroclimatic zone in Chhattisgarh state (India), the soils are undulating with 15 per cent at the top to 0 per cent slope in the valley areas. Analysis of field hydrological conditions in different soils in the toposequence revealed that in the top (sandy) soils agroforestry is a better option while in the valley areas with continuously flowing water from Mid July to November, tall varieties of rice are only suitable. In the clay loam soils rice is the best suited crop while in sandy loam soils maize is an alternative crop for diversifying rice. Local climate analysis indicated that it varies from near arid type climate at the top of the topo-sequence to near moist sub-humid conditions in the valley areas. Thus, the farmers in the zone need to plan from arid climate crops to moist sub-humid type crops like rice.

Thermal indices for suitable sowing time of chickpea in Jabalpur region of Madhya Pradesh.

Abstract: Chickpea is an important crop of the state of Madhya Pradesh. Appropriate time of sowing enables the crop to take full advantage of favourable weather condition during the Rabi season (winter), Determination of sowing time depends upon the thermal time and thermal use efficiency of the crops. Chickpea is a thermo-sensitive winter season crop. The most important factors affecting chickpea are temperature and photoperiod (Summerfield et al. 1980 and Sandhu and Hodges, 1971). Several workers (Agrawal et al. 2002, Shrivastva et al. 1990 and Sahu et al. 2007) studied the response of chickpea cultivars under different sowing times in different regions of country. The heat use efficiency of winter crop in Haryna (Rao et al. 1999), in peninsular India (Sengupta et al. 2003). Sahu et al. (2007) identified time of sowing of chickpea for optimal thermal regime under South Saurashtra agro climatic zone of Gujrat.

Optimum fertilizer in relation to seasonal rainfall in pearl millet and groundnut crops in semi-arid vertisol of Rajkot (Gujarat, India) region.

Abstract: A field experiment was conducted to select a sustainable treatment and optimize N in relation to seasonal rainfall for attaining maximum and economic yield of pearlmillet in a semi-arid Vertisol (Rajkot, Gujarat state, India). The treatments were different combinations of urea, green leaf and compost Crops was raised in eight seasons with permanent and rotation strip .Based on regression analysis, fertilizer N dose of 38 and 44 kg ha-1 at crop seasonal rainfall of 250 mm; 55 and 64 kg ha-1 at 500 mm; and 73 and 84 kg ha-1 at 750 mm was found to be optimum for targeting maximum yield of pearlmillet under permanent and rotation strips, respectively. Similarly, a dose of 25 and 29 kg ha-1 at 250 mm; 42 and 49 kg ha-1 at 500 mm; and 60 and 69 kg ha-1 a at 750 mm rainfall was optimum for attaining economic yield of pearlmillet under permanent and rotation strips, respectively in a semi-arid condition. Similar results were obtained with groundnut crop.

Study on growing degree days and population dynamics of thrips, Scirtothrips dorsalis Hood (Thysanoptera: Thripidae) on castor.

Abstract: Investigations on population dynamics against thrips on castor was carried out during the year 2002-03 and 2003-04 at Main Oilseeds Research Station, Junagadh Agricultural University, Junagadh. Peak activity was observed in 44th standard week (first week of November) and 42nd standard week (third week of October) by registering 196 and 193 thrips per flag leaf during 2002-03 and 2003-04, respectively. Maximum temperature, sunshine hours and evaporation exhibited significant positive correlation whereas, morning/afternoon humidity showed significant negative association. Path analysis showed that maximum / minimum temperature exhibited highly significant positive direct effect. Stepwise regression analysis further revealed that an increase in 1°C of maximum temperature increased the thrips population by 18.44 and 16.51 per flag leaf during 2002-03 and 2003-04, respectively, whereas a unit increase in minimum temperature and morning relative humidity reduced the thrips population to the tune of 7.19 and 2.22 per flag leaf during 2002-03 and 2003-04, respectively. The requirements of heat units for thrips build up and to attain the peaks were almost similar in both the years. Relatively higher heat units in the month of October with the end of rainy season indicated the build up of thrips population.

Rainfall pattern and moisture availability index in relation to rice (Oryza sativa L.) crop planning in eastern plateau region of India.

Abstract: Studies were undertaken to identify the quantum and distribution of rainfall with the frequency of dry spell occurrence during monsoon at Giridih, Jharkhand state, India. Rainfall at different confidence levels was calculated using mixed gamma distribution. The normal onset of monsoon at Giridih was 24th standard meteorological week (SMW) and the mean monsoon rainfall was 1112 mm. If monsoon onsets two weeks earlier (22nd SMW) than the normal (24th SMW) the total monsoonal rainfall was more than the normal with increased number of dry spells. The co-efficient of variation of June and September rainfall was very high. Moisture availability index (MAI) indicated possibility of rice cultivation from 25th SMW and the flowering stage of rice should be completed within 39th SMW (normal withdraw of monsoon). Thus to minimize crop failure, conventional cultivation of 135 ± 10 days rice could be replaced by 95 ± 10 days one, particularly in upland (without bund; direct seeded rice) and medium land (low bund land) situation.

Response of summer capsicum yield to different mulching in western ghat zone of Maharashtra.

Abstract: Vegetable crops are very sensitive to moisture stress, a little moisture stress in the soil can affect the plant growth and yield adversely. Capsicum is a highly remunerative crop of Western Ghat Zone of Igatpuri tahsil (Maharashtra) but production in the region is affected adversely by moisture deficit. The productivity can be increased by adopting improved package of practices, particularly in situ moisture conservation by mulching.

Empirical relationship of sixth order to estimate global solar radiation from hours of sunshine.

Abstract: An experiment was conducted during rabi seasons of 2002-03 and 2003-04 to quantify the light interception and radiation use efficiency for three wheat varieties as affected by variable number of irrigations with the combination of three wheat varieties viz., HUW-234, HD-2285 and PBW-154. The light interception increased successively till 90 days after sowing (DAS) and thereafter a gradual decrease was observed till maturity of the crop. Four irrigations given at CRI, late tillering, late jointing and ear head formation stages showed highest radiation interception followed by three and two irrigations, however, the lowest radiation interception was observed for wheat crop receiving one irrigation only. On an average, 19.08 % and 12.79 % increase in radiation interception was found for wheat crop irrigated four and three times respectively as compared to singly irrigated crop. Highest radiation interception was recorded with HUW 234 followed by HD 2285 at all the growth stages except 15, 30, 45 DAS. More light interception reflected in significantly superior yield and yield attributes in the order of I4>I3>I2>I1. Subsequently, radiation use efficiency (RUE) also followed the similar trend showing highest and lowest RUE with four and one irrigation respectively. Among the different varieties, HUW-234 recorded highest radiation use efficiency followed by HD-2285. The average RUE during the entire growing period for HUW-234 and HD-2285 was found to be 1.68 g MJ-1 and 1.63 g MJ-1 respectively, which was 4.83 and 1.95 % higher than PBW-154.