Aim - A long-term trial to assess how wheat responds to N and P fertilizer applications after gypsum and lime application with and without incorporation 

Key Messages

  • 60 kg/ha of N and 12 kg/ha P optimised yield under these conditions
  • Nitrogen response was significantly limited without the application of P

Table 1. Soil Test Results

Depth NO3- NH4+ OC P PBI K S Cu Zn pH[Ca] Al
0-10cm 13 1 0.6 17 23 44 7 0.26 0.38 6.1 0.2
10-20cm 7 2   8   39 17     5.1 0.3
20-30cm 3 1   5   44 29     4.8 1.0

Growing season rainfall at Perenjori was average, receiving just over the average in total and wetter than average June and July.

Methods

A factorial trial design that included three rates of nitrogen, 0, 25, 50 kg N/ha, and four rates of phosphorus, 0, 4, 8 and 12 kg P/ha with lime surface applied or incorporated and compared to gypsum.

Results:

  

Figure 1. Yield  response to N and P rates with and without lime and gypsum.

Conclusions:

  • Significant yield response to N & P rates (P<0.05)
  • Significant yield differences between lime treatments
  • The highest yields were generated from 60  kg/ha N and 12 kg/ha P