Effect of phosphorus, irrigation and Rhizobium on productivity, water use and nutrient uptake in fenugreek (Trigonella foenum-graecum)

An experiment was conducted during winter season of 2001-2004 for consecutive 3 years at Sriganganagar in Rajasthan to study the effect of phosphorus, irrigation and Rhizobiurn inoculation on seed, economics, water use and nutrient uptake of fenugreek (Trigonella foneurn-graecurn L.). Application of 40 kg P,O$ha significantly increased the yield attributes, viz. branchestplant, podstplant, pod length, seedstpod and test weight and finally the yield (8.08 qtha) over 20 kg P,O,. Phosphorus @ 40 kg P,O,/ha gave the highest mean benefit : cost ratio (1.47) in comparison with 20 (1.38) and 60 kg P,O,/ha (1.42). The highest P-use efficiency (35.95 kgtkg P,O,) was recorded at 20 kg P,O$ha, and further increase in P decreased the P-use efficiency. An increase m P level, increased the consumptive use but had no effect on water-use efficiency. Highest level of P,O, led to greater ex- traction of moisture from lower depth of rhizosphere. Application of P increased the N, P and K uptake up to 40 kg P,O,/ha. IW:CPE ratio of 0.8 significantly increased the yield (10.20 qtha), benefit : cost ratio (1.81), consump- tive water use (291.9 mn?) and nutrient uptake compared to IW : CPE ratio of 0.4 and 0.6. Higher yield attributes as well as higher seed (8.14 qtha) and stover yields (17.36 qtha) were recorded with Rhizobiurn inoculation than with uninoculated crop. Higher water use (244.8 mm), water-use efficiency (3.2 kgtha-mm) and nutrient uptake (N 31.6, P 5.5 and K 37.9 kgtha) were also recorded with the inoculated crop.