As with the N and K supply experiments, rootstock genotype was the major source of variation in shoot dry matter production under varying Si supply treatments, and volkameriana seedlings were more vigorous than seedlings of the other three rootstock genotypes (Table 10). Overall, plants grown with 2 mM Si in the nutrient solution produced approximately one third less shoot dry matter compared to seedlings grown without added Si.
As with the K and Si supply experiments, the major source of variation in shoot dry matter production under different pH treatments was rootstock (Table 14), and volkameriana seedlings were more vigorous than seedlings of the other three rootstock genotypes. The nutrient solution pH had no effect on dry matter production by any of the rootstock seedlings or on %N in shoot dry matter at harvest (Table 15).
Ed James has citrus in his veins. He has been working and thriving in the citrus business since he was a teenager — from hoeing orange trees to owning a caretaking business that serviced thousands of acres. That is, until about eight years ago.
In 2010, James looked around his personal 45-acre citrus grove and realized it was time to throw in the towel. The citrus industry in Florida had gone from over 800,000 acres to less than 400,000 acres. Citrus greening was the main culprit, but there were other factors for the decline. For James, it had just become completely unprofitable. The trees looked stunted and almost dead from foot rot, Diaprepes root weevil and HLB.
Choosing cover crops to enhance ecological services in orchards: A multiple criteria and systemic approach applied to tropical areas
Conventional agriculture is based on a high level of chemical inputs such as pesticides and fertilisers, leading to serious environmental impacts, health risks and loss of biodiversity. Pesticide reduction is a priority for intensive agricultural systems such as orchards. Reintroducing biodiversity in single crop systems can enhance biological regulations, and contribute to reduce the use of chemicals and to provide additional services such as run-off and erosion control. In tropical wet areas, weed control is difficult to manage without herbicides especially when orchards are not located in easily mechanised areas and when labour force is costly. Cover plants can be easily introduced in orchards and could be efficient in weed control and other functions. Based on this assumption, we developed a specific approach for the choice of adapted cover plants in single crop orchards to control weeds and provide additional ecological services. The approach was undertaken on citrus orchards in the French West Indies.