Productivity, nutrient uptake, soil fertility and moisture extraction pattern of summer clusterbean (Cyamopsis tetragonoloba) as influenced by irrigation and fertility levels

Abstract

Clusterbean (Cyamopsis tetragonoloba (L.) Taub.) growth indices, productivity, nutrient uptake, post-harvest soil
nutrient status, and moisture extraction pattern were examined in a field experiment that took place in the summers
of 2013 and 2014 at the Krishi Vigyan Kendra Farm of Junagadh Agricultural University on sandy loam soils. The
experiment examined the effects of irrigation and fertility levels. The sixteen treatment combinations were examined
using a split-plot design with three replications. The irrigation levels were 0.4, 0.6, 0.8, and 1.0 IW: CPE ratio, while
the fertility levels were 00:00, 10:20, 20:40, and 30:60 kg N: P2O5/ha. In comparison to 0.4 IW: CPE, the combined
results showed that 0.8 IW: CPE irrigation improved physiological growth parameters such as leaf area index (LAI),
leaf: stem ratio, crop growth rate (CGR), relative growth rate (RGR), and net assimilation rate (NAR). Additionally,
seed yield (1.33 t/ha), stover yield (2.84 t/ha), and harvest index (31.9%). At 1.0 IW: CPE, the total N intake by
clusterbean was 87.8 kg/ha, P at 15.0 kg/ha, and K at 54.9 kg/ha, whereas at 0.4 IW: CPE, the maximum soil
available N, P, and K levels were 195.6 kg/ha, 18.4 kg/ha, and 286.2 kg/ha, respectively. Under 1.0 IW: CPE, the
maximum moisture extraction from the top soil profile was 43.78%, whereas under 0.4 IW: CPE, it was 11.4 %. The
physiological growth parameters, including seed yield (1.32 t/ha), stover yield (2.78 t/ha), harvest index (32.2%), and
total N, P, and K uptake by the crop (83.2%, 13.9 kg/ha, and 51.6 kg/ha, respectively) were all improved by applying
20:40 kg N:P2O5/ha, which was equivalent to 30:60 kg N:P2O5/ha. A significantly improved nutritional state after
harvest was discovered with a ratio of 30:60 kg N:P2O5/ha (196.9, 18.3 and 274.1 kg N, P and K/ha respectively).
Soil moisture depletion was highest in the control group (42.1%), lowest in the 30:60 kg N:P2O5/ha group (39.8%),
and second lowest in the 20:40 kg N:P2O5/ha group (40.8%). But in the lowest 45-60 cm of soil, the pattern was the
other way around. In order to increase clusterbean output and maintain soil health throughout the summer, an
irrigation schedule of 0.8 IW: CPE and a fertilizer dosage of 20:40 kg N: P2O5/ha might be used.