N.SRUTHI, D.BALAGURAVAIAH, V. MUNA SWAMY, A.V.NAGAVANI

Department of Soil Science and Agricultural Chemistry, S. V. Agricultural College, ANGRAU, Tirupati-517 502, Chittoor (Dist.,), Andhra Pradesh

ABSTRACT

A field experiment was conducted during kharif season 2017 on sandy loam soils of Agriculture College Farm, Mahanandi, Acharya N.G. Ranga Agricultural University, Andhra Pradesh, to evaluate different real time and site specific nitrogen management options and performance of maize crop in terms of yield and nitrogen use effi-ciency. The experiment was conducted in randomized block design with eight treatments replicated thrice. The treatments include recommended fertilizer dose (T1), soil test based fertilizer application (T2), LCC based approach i.e. apply N25 if LCC value < 5 (T3), SPAD chlorophyll meter based approach i.e. apply N25 if SPAD value < 50
(T4), Green Seeker directed N application i.e. based on NDVI (T5), Farmer Fertilizer Practice (T6), STCR based
targeted yield approach (T ) and Absolute Control (T ). The highest grain yield of maize ( 8072 kg ha-1) was
7 8
recorded in T which received 215 kg N ha-1 in five splits but was found on par with T 3 & T 4 ( 190 kg N ha-1 in 5
5
splits), T 6 (320 kg N ha-1 in three splits) and T 7 (300 kg N ha-1). Yield attributes viz., cob length (23.6 cm), cob

weight (228.6 gm) , kernels per row (38.2) , grain rows per cob (16.8), test weight (33.6 gm ) were also higher in Green Seeker based recommendation. The B:C ratio was higher in Green Seeker based treatment (3.32) followed by LCC and SPAD based approaches (3.05 & 2.92 respectively).

KEY WORDS:

Leaf Colour Chart (LCC), SPAD Meter, green seeker, soil test Crop Response (STCR), NDVI (Normalized Difference Vegetation Index), nitrogen use efficiency, Maize