MAIZE GROWN UNDER PLASTIC HAS DRAWBACKS AS WELL AS BENEFITS, REVEALS TRIAL...
As part of our extensive maize trial research, the relative performance of a large range of varieties grown under plastic is under evaluation at a site in Devon. Although the crop has yet to be harvested there are already some interesting results.
Limagrain’s maize specialist Richard Camplin explains: “In recent years there has been increased interest in growing maize under plastic. The potential advantages of earlier drilling, earlier harvest and increased dry matter yields make plastic an attractive option for growers, particularly in more marginal areas of the country.”
The trial, sown in co-operation with J. Pickard & Co, Burrington, Devon, is evaluating the performance of varieties in terms of emergence, earliness, dry matter yield and quality. Conventional, non-plastic-covered plots of a number of key varieties have also been sown to allow comparison of the two systems.
Some interesting observations have already been made; Richard Camplin takes up the story:
“There have been some considerable differences in the speed of emergence of varieties through the plastic. Contrary to the opinion that some varieties will not emerge at all, we found that at this site, all Limagrain material emerged successfully. A number of varieties showed very good early emergence through the plastic, including Hawk, Beacon, Treasure, Sapphire and Sensation.”
During evaluation of the maize plots in mid-July, it was clear that the very warm weather of late June had had a significant effect on the varieties. Some earlier maturing varieties were already showing signs of tasselling, while later maturing varieties such as Aurelia, Award and Expert had continued to develop bulkier plants.
“One of the key reasons behind the popularity of sowing maize under plastic has been to advance harvest through warming the soil and improving growing conditions in the early stages of growth, but this cannot be to the detriment of yield. Yield increases have to be sufficient to offset the not inconsiderable cost of using plastic. This is why choosing the right variety for the conditions is very important. This trial will provide useful information to help inform these choices,” adds Mr Camplin.
Along with plastic covered plots, a number of varieties were also sown conventionally on the same date. Despite the extra addition of starter fertiliser they were considerably further behind the plastic sown plots. However, varieties such as Destiny, Andante, Award and Expert were fairing better than most. Time will tell whether these plots will be able to rival their equivalent plastic covered plots for both yield and earliness.
The trial has also highlighted some of the problems of weed control when plastic is used. Mr Camplin warns: “The field has suffered from a high population of volunteer brassicas which were not controlled by the pre-emergence Cadu-Star. This resulted in a large concentration of weeds under the plastic. A subsequent post-emergence spray of Calaris tidied up the adjacent conventionally sown plots, but on the covered plots the plastic has not started to split open until now when the plants were too big to spray. As a result weed populations around these plants are quite high.”
Limagrain will continue to monitor plant growth and development through to harvest when final yield and quality of the different, covered and uncovered, plots will be evaluated.
August 2009
Graham Parnell, Limagrain’s seed specialist in the South of England (left) and Richard Camplin, in mid July, evaluating the growth of different maize varieties sown under plastic.
