Carbon Sink Capacity and Agronomic Productivity of Soils of Semiarid Regions of India - Principles of Sustainable Soil Management in Agroecosystems - page 455

cropping seasons were obtained through INM followed by 0.78, 0.45, and 0.80 Mg
ha -1 , respectively, with 100% RDF (Srinivasarao et al. 2011d). For the entire 15-year
period, higher grain yield was obtained through the application of 6 Mg FYM +
N 20 P 13 ha -1 (2.10 and 1.49 Mg ha -1 for soybean and safflower, respectively), and it was
the least in the control (1.04 and 0.63 Mg ha -1 for soybean and safflower, respectively)
(Srinivasarao et al. 2012e). Both crops responded well to a higher dose of fertilizer
application and also to INM. Significantly higher yields were obtained through the
application of 60 kg N + 35 kg P ha -1 (1.99, 1.21 Mg ha -1 ) compared to that with appli-
cation of 5 Mg CR + N 20 P 13 ha -1 (1.79, 1.16 Mg ha -1 ); 6 Mg FYM ha -1 (1.86, 1.22 Mg
ha -1 ); and 5 Mg CR ha -1 (1.63, 0.97 Mg ha -1 ) (Srinivasarao et al. 2012e). Pooled data of
21 years suggest a higher grain yield (Mg ha -1 of rice and lentil, respectively) through
the application of 50% organic (FYM) + 50% RDF (1.95, 1.04) followed by 100%
RDF (mineral; 1.85, 0.77). Yield was on par with 100% organic (FYM; 1.75, 0.82),
and the least yield was measured in control (1.08, 0.48) (Srinivasarao et al. 2012f).
The sustainable yield index [(SYI = Y - σ)/ Ym , where Y is the estimated average
yield of a practice across the years, σ is its estimated standard deviation, and Ym is
the observed maximum yield in the experiment during the years of cultivation] also
followed a trend similar to that of agronomic yield. Significantly higher SYI was
observed with the application of organic amendments either alone or in combination
with chemical fertilizers compared to control or sole application of chemical fertil-
izers. The SYI of groundnut was also higher in 50% RDF + 4 Mg ha -1 GNS (0.48)
followed by 50% RDF + 4 Mg ha -1 FYM (0.46), 5 Mg ha -1 FYM (0.38), 100% RDF
(0.32), and the lowest in control (0.25) (Srinivasarao et al. 2012a). The highest SYI
was obtained with the application of FYM + 50% NPK (0.24 for groundnut; 0.80
for finger millet), followed by FYM + 100% NPK (0.21 for groundnut, 0.76 for fin-
ger millet) in groundnut-finger millet rotation (Srinivasarao et al. 2012b). A similar
trend in SYI was obtained in the case of finger millet monocropping (Srinivasarao et
al. 2012c). In the case of winter sorghum, the highest SYI was obtained with 25 kg N
(CR) + 25 kg N ( Leucaena , 0.48), followed by 25 kg N (CR) + 25 kg N (urea, 0.45),
and the lowest in control (0.38) (Srinivasarao et al. 2012d). In the case of pearl millet-
based systems, the SYI of all three crops was higher in 50% RDN (F) + 50% RDN
(FYM) (0.30 for pearl millet, 0.69 for cluster bean, and 0.46 for castor), followed by
100% RDN (F) (0.24, 0.46, 0.40); 50% RDN (FYM) (0.25, 0.46, 0.39); 50% RDN
(F) (0.22, 0.36, 0.38); farmers' practice (0.16, 0.34, 0.42); and lowest in control (0.14,
0.23, 0.32), respectively (Srinivasarao et al. 2011e). Similarly, significantly higher
SYI was obtained with the application of organics either alone or in combination
with chemical fertilizers compared either to the control or with the sole application
of chemical fertilizers at a lower dose in the case of safflower (Srinivasarao et al.
2012e). A significantly higher residual effect was observed in FYM compared to that
with the use of residues of soybean and safflower. The highest SYI was measured
with 6 Mg FYM + N 20 P 13 ha -1 (0.48 and 0.45 for soybean and safflower, respec-
tively) and the lowest in the control (0.41 and 0.22). In the case of rice-based systems,
the highest SYI was observed in 50% organic (FYM) + 50% RDF (0.29, 0.30) fol-
lowed by 100% organic (FYM; 0.26, 0.26), and the lowest was in control (0.17, 0.14)
(Srinivasarao et al. 2012f).