Maize response to potassium and amendments for soil acidity in La Frailesca, Chiapas, México

IPNI-2014-MEX-57

29 Apr 2016

2015 Annual Interpretive Summary


In 2015 we looked at the residual effects of lime and gypsum, and nutrients added in the previous year. One of the lime (L) x K experiments was abandoned because of poor site characteristics and errors in the calculation of lime amounts that resulted in under application. In the other L x K experiment, average grain yield in the untreated check was 1,200 kg/ha. Yields in plots that had lime only in 2014 and in those that received lime in 2014 and 2015 were 4,450 and 5,390 kg/ha, respectively, which were not significantly different. Potassium application, without lime, did not increase yields compared with the untreated check.

Because of the severe drought that affected the region, maize grain yield could be determined in only one of the L x gypsum x K experiments, with the remaining three providing just biomass data. Grain yields in the check treatment and when lime was applied only in 2014 were 1,880 and 2,650 kg/ha, respectively, a non-significant difference. Another lime application was needed in 2015 to bring about a significant yield increase to 3,090 kg/ha. The application of gypsum in 2014 had more lasting effects on yield than that of lime alone and yielded 3,040 kg/ha, with an additional gypsum application in 2015 not having significant beneficial effects. Plots where only K was applied in 2014, or both in 2014 and 2015, had yields (2,570 and 2,630 kg/ha) that were not statistically different from the check. In terms of biomass yields, results were not consistent across the three locations. The effects of liming in 2014 extended into 2015 only in one location. A second lime application in 2015 produced significantly more biomass in a second location, whereas it failed to do so in the third one. The effects of gypsum varied similarly to those of lime, whereas the applications of potassium alone – either in 2014 or in 2014 and 2015 – were not enough to increase yields significantly compared to the check.

These results must be interpreted carefully because of the influence of the drought that not only affected crop growth but also the movement and reaction of the amendments in the soil.