Wheat yield as affected by sowing rate, irrigation, and time of white clover introduction

On a fertile, moisture-retentive Wakanui silt loam Aotea wheat sown at 100 kg/ha yielded 6650 kg/ha, considerably more than when sown at 50 or 150 kg/ha. Lower yields of wheat planted at the 50 kg/ha rate were caused largely by low ear numbers, and the 150 kg/ha sowing rate resulted in the formation of many small ears. Ear size is discussed in relation to physiological factors, including carbohydrate supply during early ear development. Wheat overdrilled with white clover in September or October outyielded wheat and clover sown together in June. Irrigation up to 2 weeks after anthesis increased grain yield, and continuing irrigation through to harvest gave a further small response. Yield responses to irrigation were largely attributable to tiller survival