Dear All
I am introducing Customized Leaf Colour Chart for Nitrogen Management in Irrigated Rice -one very effective tool in enhancing use efficieny of urea at the field level . As we all know, rice is the major staple food crop of world. In present situation self-sufficiency in rice has been a major goal of agricultural research and development in most Asian countries. Nitrogen fertilizer is an essential input in most rice soils to achieve high yields. Farmers are inclined to apply fertilizer N in high amount to minimize the risk of deficiency, which can lead to excessive fertilizer application. To support decision-making on the timing of N application in rice, ICAR-IIRR, Hyderabad introduced the use of relatively inexpensive precision tools like LCC -a simple and portable tool. Farmers apply nitrogen over the optimum requirements and it may leads to more losses of applied fertilizers results in lower recovery and efficiency which is already not more than 50% . Rice production in highly permeable soil profiles with alternating aerobic and anaerobic soil conditions, applied N is readily converted to Nitrate, which is prone to leaching, nitrification-denitrification etc. . When N application is not synchronized with crop demand, losses from the soil–plant system are at higher rate. Farmers can easily use the LCC for assessing foliar N status and adjust N topdressing accordingly.
Our field experiments have henceforth proved that
LCC based N management reduces N requirement and improves the Agronomic Efficiency (AE) & Partial Factor Productivity (PFP).
Enhancement of N use efficiency in rice is very important.Application of ‘N’ through leaf colour chart (LCC) and SPAD – N technique gave nearly equal grain yield. These techniques saves about 20 – 30 kg/ha. colour charts reading recorded at critical growth stages were closely correlated with grain yield. Colour charts of different green colour gradient was prepared and made available to farmers. The customized LCC developed at ICAR-IIRR, Hyderabad on the basis of spectral evaluation of leaves of hundreds of varieties under different N levels can be used for real time N management by using the N application schedules (20-30 kg N/ha depending on the crop stage). Grain yield, AE-N and PFP-N was enhanced in both during wet and dry seasons ( 5.33 t/ha), 38.14 and 68.64 ).
How to use?
1.Start taking LCC readings from 14th day for Transplanted and 21st day for Direct seeding when basal not applied.
2.If basal ‘N’ (DAP or NPK) is applied take LCC readings at 21-25 DAT for Transplanted; 28-30 DAS for Direct Seeding.
3.Take 10 readings during (8-10 A.M.) from fully expanded, top most and healthy leaf of the 10 plants. (one reading/plant).
4.4. If 6 of 10 readings below the critical LCC 3 value apply ‘N’ as mentioned.
Kharif – 20-25 kg N/ha
Rabi : 25-28 kg N/ha
5. Repeat LCC readings for every 7 days to judge correct time of ‘N’ top dressing.
ADVANTAGES
LCC is an easy-to-use and inexpensive diagnostic tool.The LCC can be used by the farmer himself to rapidly assess leaf nitrogen status and to decide the amount and time of nitrogen application.Helps to maintain optimal leaf nitrogen content of rice crop, which can be vital for achieving higher nitrogen use efficiency and better yield. Reduces the insect pest infestation.Reduces the cost of cultivation for rice
Д-р. BRAJENDRA PARMAR