Maize, known as Corn in Canada and USA, really is an “amaizeing” crop.
This year I grew about 0.6 ha., say one and a half acres, in what I call the Ribeiro Grove, this being the latest grove to be planted and as detailed in previous posts. In addition to the local forage variety I trialled 3 non-GM hybrids. In order of maturity the varieties were Local forage, Suzy, Surreal and PR33A46. The first two hybrids are from Dow and the third from Pioneer.
The last soil test was in the spring of 2010 with results of a pH of 6, 4.5% organic matter, with high levels of both phosphate and potash, and much improved on a 2004 test, particularly pH and OM. Since 2010 the land has received a further three tonnes/ha of ground limestone plus estimated maintenance levels of P and K to suit the forage crops grown in summer 2010 and winter 2010/11 together with nitrogen for production. The local forage variety was sown on part of the area in summer 2011, and mainly cut green for feed, with a tiny amount allowed to ripen for the grain. This crop was very poor due to severe weed infestation despite two cultivations with the tractor and a lot of hand work too.
The main purpose of this piece of ground for the next several decades is the production of olives from 180 trees. Inter-row cropping must not be at the expense of the olives, so it is necessary to be generous with fertiliser and to maintain or improve the OM. This means that as much as possible of the crop residues need to be returned to the soil. At the same time the crops are required to feed my goats, consequently the aim of the 2012 maize crop was first to make use of the ground amongst the young olive trees without depleting them of any nutrients; next to produce some green feed for the goats (absolutely essential in what turned out to be a desperate year for fodder given a dry 2011/12 winter); then OM to return to the soil, and finally, if possible, to harvest some grain.
To recap – the olives are at 6 x 6 metres spacings in a wedge shaped piece of land. Using my home-built two row seed drill I fitted 8 rows in between each long row of trees, leaving about 60cms each side of the line of trees bare. The whole area can be irrigated by overhead sprays – provided the river keeps flowing. Prior to sowing on 17th May, and after soil temperatures had been or exceeded 18ºC for five consecutive mornings, I incorporated 20.5%N fertiliser at a rate of 750kgs/ha. 98mm of rain had fallen between 2 and 3 weeks prior to sowing. There was no rain after sowing. Sowing rate was heavy at about 120,000 seeds/ha or 48,000 to the acre. I am happy with this rate since it is much easier to thin a crop if necessary than it is to try and make up a shortfall after emergence. Seedlings pulled up by birds is sometimes a major problem. Magpies are the culprits here, and this year took all my sweetcorn except five plants. It is normal practice in many countries to sow heavily, and to use the thinnings for sheep or goats.
Immediately after sowing I sprayed the pre-emergent herbicide Activus and watered it in with a light irrigation. I also had Laddock Plus available as a post-emergence, but this was only required in a few isolated spots where I think I had not been sufficiently accurate with the pre-emergence. The field had previously shown extremely heavy infestations of a variety of summer weeds, and is just as bad in the winter, and I had been unable to control them.
The crop germinated well and grew at a rate of between 25 and 30 cms per week, the Pioneer variety reaching a maximum height of 3.20 to 3.25 metres. The others were not so tall. At the beginning of June all pasture on the property had dried off and total hand feeding of stock was necessary. The river was falling rapidly and I began to feed maize thinnings, taking the plants least likely to survive lack of water first. Within a few weeks I realised some of the plants were not setting grain and I concentrated on harvesting these in preference to those with grain. From late July I was using plants that had set grain too, aiming for 50% of the plants used each day.
With a planned goat mating period to begin on 17th September I increased feed levels by giving an additional daily feed of immature cobs, including the husks. This increasing level of feed for a few weeks prior to mating is known as flushing, and is of great benefit to all livestock. I always increase hard feed levels over a six weeks’ period before joining and maintain that level for six weeks more, then reduce over the next few weeks. How much is fed depends on many factors, but mainly other available feed and the condition of the animals.
These cobs were used from 6th August onwards by which time the CHUs were 1807. The plants that had cobs removed were left in the field for OM. This harvesting was continued until 22nd September (storing an increasing quantity as the cobs were maturing) on which date I completed the harvest. CHUs totalled 2918 at 128 days from sowing. I de-husked the mature cobs in the field and put the ears to dry in the sun - on a tarmac area at first then in open weave bags as they became drier. I harvested by hand so had to commence whilst the cobs were a long way from being dry. I may have lost a very slight amount of yield by commencing very early, but not much. Since I did all the harvesting myself I was able to ensure that each bag held the same volume of ears.
So far as production is concerned, the Pioneer variety produced the most fodder because of its height, and also the biggest cobs where they were left to maturity, but too many of them failed to set grain. If growing only for fodder and no grain this would be my choice of variety. The local un-named variety produced small cobs and not as much fodder as any of the others. There was extremely little insect damage throughout the crop, but this variety had a disproportionate amount and I will not be using it again. Suzy was sown on the driest ground and most of it was cut for fodder, but produced cobs on virtually every plant, although smaller than the other hybrids. Remember this is the earliest of the hybrid varieties sown, so smaller grain yields are expected.
The best yield of grain on visual appraisal was from Surreal and I left an area of 72 x 6 metres, including bare ground each side of the 8 rows in the area, to be harvested when mature. This 432 sq. m. is close to one tenth of an acre, so, mixing Imperial and metric measures, a little mathematics allows us to calculate yield. Some test weighing of shelled sample bags of the total harvested showed that there was marginally more than 300kgs of dry grain from this area. That is 3 tonnes to the acre or 7.4t/ha. Not a world beating yield, but good under the circumstances of a bad season together with having approximately 20% of the land uncropped due to the bare strip either side of the olives. Add an extra 20% and the yield per hectare becomes very acceptable in a bad season.
Whilst costs and value of the crop obviously vary from country to country and year to year, my costs for this year were Seed €150, Fertiliser €150, Sprays €25 and electricity for irrigation approximately €80. This gives an overall cost of €405. In addition to these costs there was, of course, work with the tractor. This is where costing becomes slightly inexact when more than one crop occupies the same piece of ground, but if the proportion of fertiliser, spray and irrigation costs attributable to the olives is cancelled out by the proportion of the tractor costs attributed to the maize (and that is being generous to the olives) we can leave the costs as they are. The dry grain in store was very close to one tonne with a value of about €400 so the stored grain covered the cost of producing the crop. This may not seem like a big return, but overall it was very profitable.