Long-term effects of integrated nutrient management on productivity and soil fertility in pearlmillet (Pennisetum glaucum) – mustard (Brassica juncea) cropping sequence

A field experiment on integrated nutrient management (INM) was initiated during kharif season 1997 at Gwalior under pearlmillet [Pennisetum glaucum (L.) R. Br. Emend. Stutz] — mustard [Brassica juncea (L.) Czern. & Coss.] cropping sequence. The treatment 100% NPK + Farmyard manure (FYM) (@10t/ha/year) + Azotobactor + phosphate solubilising bactria (PSB) provided highest yield of straw (8.60 t/ha and 6.79 t/ha) and grain (4.07 t/ha and 2.34 t/ha) with net monetary returns (30,695 /ha and 36,514 /ha) in pearlmillet and mustard respectively and recorded the highest system productivity (10.0 t/ha). This treatment also increased OC (0.52%), available N (238 kg/ha), P2O5 (24.8 kg/ha), and K2O (218 kg/ha), sustained soil pH (7.54) and EC (0.23 dS/m) over all other treatments. Continuous application of organic manure along with optimal dose of fertilizer (100% NPK+FYM @10t/ha/Y) was beneficial in enhancing crop productivity and soil fertility. Treatment receiving seed inoculants (Azotobactor and PSB), and FYM in combination with chemical fertilizers showed positive influx of N, P and K over unfertilized control and other combinations of fertility. The B: C ratio was higher for chemical fertilizer along with Azotobactor and PSB in pearlmillet (4.0) due to lesser cost of cultivation compared to other treatments, where as it was highest (4.0) with 100% NPK+FYM (@10t/ha/year) + Azotobactor + PSB in mustard. Thus, INM with organic manure, inoculants and chemical fertilizers not only provided higher productivity but also sustained the soil fertility.