After our eventful journey to Obregon in Sonora, Mexico, we headed to our hotel and set up ready for the next day. We arrived by taxi at CIMMYT the International Maize and Wheat Improvement Centre. We met up with Maria Elena Cardenas, who knows all about crop nutrition. In conjunction with OSU (Oklahoma State University) the team here developed the first Green Seeker device for measuring the crop biomass (NDVI- Normalised Difference Vegetative Index). From this measurement an algorithm can be worked out to give a value and fertiliser can be adjusted accordingly. Fertiliser and water quality is a huge issue in Sonora, with water for crops being used from a series of wells and one major the Alvaro Dam. Here I am pictured (left t right) Maria's team, Jose' Cynthia, Marisol, Maria, Lorena and Alberto. They are currently working on a similar project to the green seeker but measuring the levels of Phosphate in the plants to give fertiliser requirements.
After Maria and her team we headed around the corner to meet Manuel R. Velenzuela from PIEAES. This is a farmers research organisation, located at the Obregon site. Manuel gave a really great insight into the issues affecting the farmers of the Sonora area and specifically in the Jaqui Vally. Water is a crucial issue here in the area with crops having to be irrigated from either wells, down to 250m, or from the Arvaro Dam. There are issues between the two counties about the ownership of the water. We talked about land values and land ownership after the revolution, and the links with CIMMYT. We talked about the fact that some farmers are still growing varieties that are 20-30 years old but recently they have been growing newer ones resulting is higher yields, breaking their yield plateau, is that something we should look at in the UK? Rust is a major issue here and newer varieties have to have this as the first goal for new varieties, then comes end use quality and finally yield. Much of the wheat grown here is Durham wheat and is exported through Africa to Europe. Average yields of 7.2 were recorded last year although the common average would be about 6.8t/Ha.
The soil was quite sandy in Obregon and with very little organic matter. The fields are still cultivated with minimal or full cultivation and it reminded me of the situation in the Dakota's I heard about from Dwayne Beck the previous week. Would cover crops and zero tillage help, leaving the trash on the surface to keep the soil cool when the weather is hot as Steve mentioned? It's all starting to come together!
The soil has very low organic matter in the area so where possible cover crops are being grown. Here Rodrego was showing us a little about the crop called Sesbania. This is a legume that will grow to 2m tall in 12 weeks, with great nodulation and a fantastic tap root. These crops were only 4 weeks old and had already grown to about 50cm. The crop will be flailed off later in the season and spring wheat will be planted into the residue. Although its a spring wheat it get planted in the winter and will grow for just 5 months, from the middle of November. The crop may have 3-4 passes with the irrigator, each time delivering between 80-100mm of water.
In the afternoon we headed out to the Alvaro Dam. The key for agriculture in the area is held in these waters and I can see why there are starting to be issues. The water must have been at least 20m below the full level although it is at the end of the season. This part of Mexico gets 300mm of rain over 3 months, July, August and September (summer). The Dam was very low and as a result many of the summer crops were not being grown as farmers could not get the water to enable further cropping. It was very good of the CIMMYT team to take us out and show us around the local area.