Real-Time Nitrogen Management in Rice Genotypes through Leaf Colour Chart at Critical Growth Stages

摘要

Although recommendations for monitoring of N status through leaf greenness at regular intervals of 7 to 10 days are available,but farmers are habitual of applying N only at the critical growth stages.Six panel inexpensive leaf colour chart(LCC)was evaluated for site specific N management in rice varieties Jaya,Gurjari and GNR-3 on clay soil with panel number 3,4 and 5 over regular farmers'practice at 100 and 80 kg N ha~(-1)levels at Navsari Agricultural University,Gujarat for three years(2014-16).Periodical N requirement to rice was evaluated through weekly LCC observations at tillering and panicle initiation stages.Variety-wise weekly N requirement was found to be different.All the three varieties did not have significant influence on their yield potential.Variety Gurjari was significantly superior to the other varieties and gave highest growth,yield,quality and economics.Among three LCC panels tested,earliest N hunger was shown by Gurjari followed by GNR-3 and Jaya in that sequence.Due to more greenness,LCC 5 showed N demand earliest and LCC 3 expressed most late N demand.LCC 4 showed the highest growth,yield,quality,economics and NUE followed by LCC 5 over LCC 3 and farmers'practice.Among two levels of N tested,application of 100 kg N ha~(-1)gave highest growth,yield,quality and economics over 80 kg N ha~(-1).All the NUE-related parameters obtained at 80 kg N ha~(-1)were significantly superior to those at 100 kg N ha~(-1).