The effects of crop rotation and fertilization on wheat productivity in the Pampean semiarid region of Argentina 2. Nutrient balance, yield and grain quality

Wheat (Triticum aestivum L,) in the semiarid region of Argentina has often been grown as a low-input crop. Rainfall scarcity and distribution are the main characteristics of the region. Consequently, a knowledge of the effect of different management practices is the key to sustainable crop production, The objective of this work was to study the effect of 15 years of different wheat management practices on plant nutrition, dry matter production and grain yield and quality. The treatments were: continuous wheat (WW), wheat-grazing natural grasses (WG) and wheat-legume: [vetch (Vicia sativa L,) plus oat (Avena sativa L.) or Triticale (Triticum aestivum L, x Secale cereale L,)] (WL), with and without fertilizer (N + P) application. The WW and WL treatments involved annual tillage and a long fallow period (4-6 months) under stubble mulch, and WG involved annual alternate tillage and a short fallow (1 month). The experiment was started in 1975 and the data presented were obtained in 1989, Wheat yields were higher with the WW than with the WG rotation, but in both rotations fertilization was required to obtain better grain quality (protein content higher than 11 per cent). The wheat-legume rotation resulted in the highest yield, protein content, and better yield components. Fertilizer application did not increase dry matter production but improved nutrient uptake and grain quality. Yield component differences could be attributed to water availability due to different fallow length. The wheat-legume rotation seemed to be the best practice in the semiarid Pampean region. (C) 2000 Elsevier Science B.V. All rights reserved.