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July 16, 2018

Soybean/Sugarcane Rotation becoming more Popular In Sao Paulo

Author: Michael Cordonnier/Soybean & Corn Advisor, Inc.

Sao Paulo is the largest sugarcane producing state in Brazil and sugarcane producers in the state have been increasing the use of soybeans as part of their sugarcane renovation. Ideally, sugarcane should be replanted after five harvests, because that is when the yields start to decline. In order to help to defray the cost of renovation and also to improve the soil fertility, some sugarcane producers have been planting one year of soybeans before the sugarcane is replanted.

Renovating a sugarcane field is estimated to cost approximately R$ 7,000 per hectare (approximately $750 per acre) and planting one year of soybenas can defray as much as 40% of the costs. The soybeans are usually grown on a contract basis and the landowner usually receives 10% of the gross value of the soybean crop.

In addition to monetary gains, the soybean crop fixes its own nitrogen and some of that residual nitrogen is left behind in the soil for the subsequent sugarcane crop. Fertilizers applied to the soybean crop can also help to improve the soil fertility for the subsequent sugarcane crop. Sugarcane is grown on many different types of soils, some of which are not suitable for soybean production. Therefore, for this type of crop rotation, the sugarcane producer must select the soils best suited for soybean production.

It is estimated that in 2017 there were 333,000 hectares of soybeans used in this type of rotation and it is expected to continue to increase on an annual basis.

Soybeans that are used in this type of rotation should have certain characteristics. First, the soybeans should be early maturing varieties. A maturity of less than 120 days is preferred and if possible, less than 110 days. The short cycle soybeans allow for more time to plant the subsequent crop of sugarcane.

Second, the soybeans need to set their lowest pods as high as possible off the ground. Many sugarcane fields are located in hilly and uneven terrane, so it would be difficult to harvest the lowest pods if they are set very close to the ground. The height of the lowest pods can vary by variety, so that characteristic should be taken into account when choosing a variety of soybeans.

Various seed companies in Brazil are conducting research to develop soybean varieties that are suited for this unique type of rotation.