Effect of various levels of nitrogen fertilizer on nodulation of pea cultivars

A field experiment for two consecutive growing years (i.e., 1999-2000 & 2000-2001) was conducted on four pea cultivars viz., Arkel, climax, green feast and olympia in response to different levels of added N fertilizer under the existing climatic conditions of district Mastung, Balochistan. Seven N fertilizer treatments (T-1 to T-7) were applied @ zero (T-1); 60+40 kg P2O5 & K2O ha(-1) (T-2) and 25, 50, 75, 100 & 125 kg N ha(-1) (T-3 to T-7) plus a constant dose of 60+40 kg P2O5 & K2O ha(-1). These N treatments were applied to each sub-plot (except T-1 & T-2) in two halves. The first one was applied at the time of initiation of flowering, while the 2(nd) one at the time of pod formation. Results showed that most of the mentioned entries of pea CUltivars responded significantly and cultivar Arkel took the top position. Results also showed that applied N fertilizer significantly and linearly reduced all mentioned attribute of nodules. However, applied P2O5+ k(2)O slightly improved it. Numerically a maximum number of nodules (9.23 plant(-1)), number of effective nodules (6.67 plant(-1)), number of ineffective nodules (2.65 plant(-1)), fresh weight of nodules (5.43 g plant(-1)), dry weight of nodules (1.78 g plant(-1)), and moisture content of nodules (35.2 g kg(-1)) were found in applied fertilizer @ 0.0+60+40 kg NPK ha(-1). It was further revealed that all mentioned attributes except moisture contents were highly significant (p < 0.01) but negatively correlated with fresh pod yield plant(-1).