Nitrogen Management in Rice through Leaf Colour Chart under Kashmir Conditions

Large field to field variability restricts efficient fertilizer management when broad based blanket recommendations are used in rice. Hence, the nutrient management for rice requires an approach that enables adjustments in nutrient applications to accommodate the sitespecific needs of the crop for supplemental nutrients. This study was conducted to establish and evaluate the threshold leaf colour value to guide in-season need based fertilizer N top dressing in Pusa Sugandh-3. For this purpose various growth parameters, yield parameters, grain and straw yield were measured in both years. Almost all the measured parameters in LCC 4 @ 20 kg N ha were significantly higher than remaining LCC and fixed time N management treatments as well as control. Following the principle that threshold value is the one which simultaneously optimizes grain yield and NUE, LCC 4 @ 20 kg N ha was adjudged as the threshold value for real time nitrogen management in Pusa Sugandh-3. INTRODUCTION Rice (Oryza sativa L.) is the main staple food crop in India including Jammu & Kashmir. Globally, India stands first in area (36.95 m ha) and second in rice production (120.6 m tonnes) next only to China. In Jammu & Kashmir, rice is being cultivated on an area of 261.35 thousand hectares with a production of 761.1 thousand tonnes (Economic Survey, 2010). Fertilizer nitrogen is a key input in rice production. In the coming time, Indian agriculture is likely to witness a delicate balance between inputs and outputs of reactive N (Singh, 2014). Substantial N inputs are required to be supplied to rice ecosystems to produce sufficient and high protein food for ever increasing population but at the same time minimal loss of this nitrogen from agriculture to other ecosystems must be ensured. Therefore efficient nitrogen utilization is must to produce more food with less N inputs. In India current N fertilizer recommendation in rice consists of fixed rates and timings for vast areas of land having climatic conditions. Owing to huge field tofield soil N variability, efficient use of N fertilizer is not possible when broad-based blanket recommendations are used (Adhikari et al., 1999). One of the primary uncertainties faced by farmer is decide the time and amount of fertilizer N to be applied (Lobell, 2007). These uncertainties can be reduced by knowing the N supplying capacity of the soil. Huge portions of applied N are lost due to the lack of synchrony of plant-N demand with N supply. Thus improvement in the synchrony between crop-N demand and N supply from soil and/or the applied N fertilizer is likely to be the most promising strategy to increase N-use efficiency in cereal crops. The crop demand-driven site-specific N applications have the potential to add to farmers’ productivity and profits and are crucial for achieving high yield and N-use efficiency (Singh, 2008). With this background, the current study was carried out at main campus SKUAST-K Shalimar to determine optimum nitrogen rate of rice variety ‘Pusa Sugandh-3’ through real time management approach using leaf colour chart (LCC). Materials and methods: The field experiments were conducted at the University farm of SKUAST-Kashmir; main campus Srinagar during kharif season 2013 and 2014. The site is situated at 34-08ʹ N latitude and 74-83ʹ East longitude having an altitude of 1587 m above mean sea level. The average precipitation is 780.77 mm (average of past 28 years), most of which is received from December to April in the form of snow and rains. Atmospheric temperature ranges between the lowest winter temperature of −8C to the highest summer temperature of 33C. The mean meteorological data recorded during 2013 and 2014 at Meteorological Observatory, Division of Agronomy, Shalimar are presented in Fig.1 & 2 respectively. The experiments consisted of eight treatments laid out in randomized completely block design (RCBD) in three blocks. Treatments included a control (N0), three fixed time N (60, 90 and 120 kg N ha-1) and four real time N management treatments. In fixed time treatments, total N was applied in split doses at three predetermined stages i.e. 50% as basal dose and 25% each at mid tillering and panicle initiation stages. In real time N management Nitrogen Management in Rice through Leaf Colour Chart under Kashmir Conditions Aabid. H. Lone, Mumtaz. A. Ganie, a Division of Soil Science, Sher-e-Kashmir University of Agricultural Sciences & Technology Kashmir Shalimar, Srinagar J&K 190 025 (India) International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 http://www.ijert. org IJERTV6IS060045 (This work is licensed under a Creative Commons Attribution 4.0 International License.) Published by : www.ijert. org Vol. 6 Issue 06, June 2017