EXPERIMENT

Sowing Soya into Rye

Following the soya into rye experiment N°1, the plan was to improve soil protection and decompaction by adding vetch and structural radish into the cover. The field was one in which the former owner had grown many years of irrigated maize crops, resulting in an infestation of Datura (which had led to the last soya crop here being destroyed) and a very high pressure from all spring/summer weeds. 2014/15 experience showed that Datura was successfully controlled by the rolled cover crops / no till. I hoped that a good stand of rye/vetch would also deal with enough of the other weed pressure.


Rye radish and vetch emerge. Sown 30.09

10.11

Three different mixes were sown. Vetch 40 / Rye 40 / Radish 8

Rye 80/vetch 25/radish 8 (right) rye 80 vetch 25 (left)

08.12

04.02 Rye vetch radish on right. Rye vetch no radish on left. Marked difference in developement of rye and vetch in presence of radish. Competition for light? Stimulation of microbiomiel activity?

04.02 vetch 40kg rye 40kg radish 8kg mix. Radish being overtaken by vetch. Rye struggling.

Vetch Rye Radish

Vetch Rye no radish

21.03 Marked difference between radish / no radish continues.

Left hand rye and vetch from section with no radish, right hand from section with radish.

Vetch 40/rye 40/radish 8 Radish in flower. Rye overwhelmed.

Vetch/rye/radish mix. The clear white line of radish flowers marks a ‘fertility limit’ between the part of the field that was cropped and the part that the former owner kept as pasture until 2 years before we took over. The soil has a much darker colour and crumbly texture in this part of the field, in stark contrast to the pale yellow clay elsewhere.

30.04 rye vetch

30.04 Vetch rye. Rye practically non existant. Low fertility conditions have allowed nitrogen fixing vetch to dominate.

High fertility of the part of the field which was formerly pasture means vetch has been unable to dominate and suppress weeds. Next time I’ll sow rye dominated mixture for these conditions.

08.06 Late flowering vetch held back rolling. Need to change varieties.

09.06 Rolling complete

26.06 Lots of neighbours are losing whole fields, soya included, to slugs. Changed soya variety to an early one so I could wait a little longer and sow when the soil moisture was on the way down.

07.07

Good germination of soya and maize. Then disaster. The leaf beetle came to attack the dying vetch, which was to be expected. But due to the soya being in the same family , it quickly switched to the young soya leaves. This was definitely the problem because in the small area I’d sown as pure Rye, the Soya was unaffected.

Given it’s visual similarity to cabbage flee beetle which I’ve successfully controlled in the veg patch by keeping the leaves of affected plants well watered, I tried the same thing here. It was effective but it was too late to begin an irrigation of the field to try and save it. Soya regrowth became a disastrously expensive summer pasture.

Conclusions

As a result , I’ve modified plans for sowing wheat into a Sorghum cover. I thought this could be interesting due the sourghum’s frost sensibility and ability to grow during late summer, in time for rolling down as a mulch for the wheat at the end of October. Instead, I’m going to try things from different botanical families – Nyger, Camaline, Buckwheat. A costly lesson: Cover crops for rolling must never be in the same family as the cash crop to follow.