Reversing yield declines of a sub‐tropical vertisol uri icon

abstract

  • Problems of declining yield and increased chlorosis have been noted for maize (Zea mays) grown at CIMMYT's experiment station at Tlaltizapan, Mexico. Yields predicted by a crop model based on temperature and incident radiation showed no decline with time, suggesting that the problem was related to soil factors and/or management. Neither soil organic matter (SOM) nor pH were implicated, as SOM increased by 58%, and soil pH remained unchanged over the 15 years studied. Through a procedure of spatial and temporal analysis, the problem was hypothesized to be a combination of bicarbonate ion (HCO3(-)) induced iron (Fe) chlorosis and soil structure deterioration. Given this hypothesis, a trial was established to evaluate the effect of different cover crops on soil moisture and the subsequent yield of maize. In addition, blocks were sown to alfalfa (Medicago sativa) with the intention that drying of the soil profile would re-establish soil structure. Yield results from the cover crop trial, plus improvements in infiltration and growth in blocks sown to alfalfa, supported the conclusion that changes in management could, at least partially, ameliorate the degradation of soil structure on this station.

publication date

  • 1995
  • 1995
  • 1995