Evaluation of agroforestry systems for maize (Zea mays) productivity in South Africa

Abstract

Maize (Zea mays L.) is the staple food crop grown by most smallholder farmers in South Africa. Decline in soil fertility and expensive chemical fertilisers affect maize production by these farmers. Smallholder farmers cannot afford chemical fertilisers because these are expensive. Agroforestry systems offer cheap alternatives to expensive chemical fertilisers. A field experiment was established in the 2015/16 season at Wartburg. The objective of the study was to evaluate maize yields and productivity in agroforestry systems. The experiment had five treatments: sole (maize; pigeonpea; or Sesbania bispinosa); maize + Sesbania bispinosa; maize + pigeonpea laid out in a randomized complete block design replicated three times. The yield was in order: sole maize > maize + pigeonpea ≥ maize + pigeonpea. The land equivalent ratio (LER) was in the sequence maize + pigeonpea > sole pigeonpea > maize + S. bispinosa > sole S. bispinosa ≥ sole maize. Maize yield might be increased in the following season as a subsequent crop in the same field because of residual nutrients that would have been enhanced and set free for plant uptake during the previous season. Pigeonpea is recommended in agroforestry systems with maize because of its higher LER and combined production of grain for human and livestock consumption and firewood.