Determination of the Length of Growing Period for Crop Planning in the North Central Plateau Zone of Odisha

Abstract

The LGP of an area varies temporally, spatially with the climate. It is considered as the period from onset of monsoon rain to the cessation of rainfall. It is the major factor to decide which variety of crops to adopt in an area. The length of growing period(LGP) is the duration of the season or number of days when plant growth takes place. Information on LGP provides a basis for the selection of crops, cultivars (short / medium / long duration) and cropping/farming systems of a region.The study aims to estimate the length of crop growing season of the North Central Plateau Agroclimatic Zone of Odisha in order to provide an efficient crop planning for the region.In this study the LGP, annual, seasonal, monthly and weekly rainfall values were computed using daily rainfall data of 31 years(1989–2019) for two districts (Keonjhar& Mayurbhanj) under North Central Plateau Zone of Odisha. The growing season begins when the sum of daily rainfall (forward accumulation) reaches 75 mm (28 May, 29 May…15 Oct) and ends when backward accumulation (15 Oct, 14 Oct…,28 May) reaches to 20 mm. The LGP was computed by adding the duration of the rainy season with the sum of post-monsoon rainfall and the average water-holding capacity of soil divided by the post-monsoon PET of the district. LGPs obtained by the above method varied from 177 to 278 days in this zone with Baripada block of Mayurbhanj District having the highest LGP of 278 days and Saharpada block of Keonjhar has the lowest (177 days). The analysis revealed that the monsoon starts effectively from 22 SMW (12June to 15th June) in Keonjhar district and 23 SMW in Mayurbhanj district remain active up to 41 SMW(9th October to 13th October).Since, rainfall is unimodal in North Central Plateau Zone and we are having around 25–32 weeks LGP, intercropping and sequential cropping can be taken in most of the blocks and double cropping in some of the blocks wherever irrigation facility either as groundwater or surface is available.  The present study reveals that the overall mean annual rainfall of the North Central Plateau Zone was 1451mm with an average of 66 rainy days.On upland and medium lands, early sowing of pre-rabi crops like cow pea, horse gram, green gram, black gram, niger, tomato, cabbage, cauliflower, okra, and leafy vegetables to be done to conserve soil moisture.