Farmers like to be given a programme for virtually everything, but the truth is this isn’t practical. Soil composition is a variable, as is the amount of rain.
It’s better for farmers to learn to “read” the crop by its colour and growth and refine practices with the knowledge and experience they gain every year.
Experience and observation allow a farmer to get maximum yield from minimum input. Any excess inputs can reduce yield in some cases and will push up costs relative to the yield.
Amount of nitrogen needed
The amount of nitrogen needed is influenced by what’s already in the soil, either as directly available applied nutrients, or what will become available through the mineralisation of organic matter. Clearly, it will be different for every type of soil.
In the case of baby marrows, an excess of nitrogen will be wasteful, but not as harmful as excess nitrogen for pumpkins. This excess is more harmful when the spacing is close. It may result in longer internodes and cause the plant rows to close up before sufficient fruit has been set, causing plants to start aborting subsequent fruit.
If the nitrogen level is too low, the plants are rendered more susceptible to disease and may not even be able to cover the whole area (in the case of pumpkins), which means all the sunlight on the land can’t be used for producing energy and therefore for producing fruit.
With pumpkins, we need to keep an eye on the colour and vigour relative to vacant ground and variety. The management practices needed to get the most out of each variety are slightly different, because each variety has different bearing habits.
By considering the principles outlined in previous articles in this series, we can make observations which will help fine-tune nitrogen application. This not only makes farming more profitable, but also much more enjoyable.
With pumpkins and many other crops where fruit and not leaves are harvested, too much nitrogen tells plants they have an opportunity to dominate and cover as large an area as possible, while often producing less fruit or even aborting fruit. The plant isn’t aware doing this means the rows will quickly close up, bringing it into competition with other plants. At this point, another mechanism will kick in as the plant dedicates itself to maintaining the existing fruit set and aborts future fruit. This is a safety mechanism to ensure it can bring all the seeds which are already set to maturity. – Bill Kerr (Contact (016) 366 0616 or e-mail [email protected]). |fw
