Study of the agronomy of chickpea (Cicer arietinum L.) in Canterbury

The potential of chickpea as a new grain legume crop for Canterbury was evaluated in both field and glasshouse experiments. Seed of the kabuli type was sown in a Templeton silt loam soil at varying plant population, with and without inoculation with rhizobium under rain fed and irrigated conditions, and at different dates during spring. The response to nitrogen fertilizer was also investigated in a glasshouse experiment. Crop productivity was related to the duration of crop growth. Highest total dry matter and grain yield were obtained from a September-sown crop when growth duration reached 120 days. Seed yield decreased from 270 to 206 g/m² as sowing date was delayed from September to late November. This decrease was strongly related to the total amount of intercepted PAR and to the accumulated soil moisture deficit. When grown at populations ranging from 33 to 133 plants /m², yield per unit area decreased from 254 to 228 g/m² as population increased. A quadratic response was also detected. However, under the conditions of this study a population of about 33 plants /m² appeared to be adequate to produce optimum seed yield. Yield reduction at high plant population was associated with a significant reduction in the number of branches and number of pods per plant. Atypically wet weather conditions, particularly during the latter part of the 1983/84 growing season, not only masked the effect of irrigation but also showed the sensitivity of chickpeas to humid and cloudy weather conditions. The crop developed excessive vegetative growth which had a deleterious effect on seed-set. This response also highlights the risk of late sowing as the crop only had a limited period to mature before the onset of low autumn temperatures. Inoculation with rhizobium strain CC1192 increased yield by 29%, from 161 to 208 g/m². The benefit of inoculation was also shown in a glasshouse pot trial where dry matter yield was significantly improved. This suggests the need for inoculation with appropriate rhizobia where the crop is sown for the first time. An important interaction was observed between nitrogen application and inoculation. Nitrogen applied at planting had a detrimental effect on symbiosis whereas application of 30 kg N/ha thirty days after sowing allowed the plants to utilise both the applied and fixed nitrogen without interfering with the nodulation process. This implies a possible need for nitrogen fertiliser application in fields with low soil N status. It can be concluded from this work that chickpea has the potential to yield well under Canterbury conditions. Given appropriate agronomic management the crop could become a useful and potentially profitable alternative legume in crop rotations