A wet Spring

Ajay Nair

Department of Horticulture
Iowa State University

This past week I time traveled to my nursery days and the song which I wanted to sing badly was "Rain rain go away...Come again another day, Little Johnny wants to play". Things have been fairly wet this spring. The ground is saturated and it is hard to get in the field and plant. We need the rain but it is the timing that is causing  issues. It rains and the ground starts to dry in 3-4 days but then it rains again. As compared to last year we are late in our plantings. Last Tuesday we flail mowed our cover crops (cereal rye) and gave a shallow till to dry the soil faster. We waited for three days and last Friday when we got a small window, we went full throttle and banded fertilizer and laid plastic. Banding fertilizer in the area where the plastic is laid has several advantages:

1. Less fertilizer is used

2. Fertilizer not available to weeds that grow in the alley-way between raised beds

3. Promotes sustainability by reducing fertilizer usage

Above: Cover crops being flail mowed
Below: Plastic mulch layer in action

It is unfortunate that the rain is disrupting and delaying planting, but vegetable growers should take utmost care before deciding to run any machinery in their fields. One of the concerns is soil compaction. Under wet conditions, the effect of soil compaction could go as deep as 2 feet, depending upon the axle load of the tractor.  Heavily compacted soils contain few large pores and have reduced rate of water infiltration and drainage in the compacted layers. This can can increase runoff, thus increasing soil and water losses. Compaction directly limits root growth of crops and has the potential to reduce crop growth and yield. This year it might a little tight to find the perfect soil moisture or field condition to lay plastic mulches, all we can do is be prepared and ready to get in to the field as soon as there is an appropriate rain-less window. Meanwhile, on a lighter note, I will continue with my nursery rhyme.....Rain Rain go away....come again another day......

Normal and compacted soil
(source: landscapesource.com)