How does one start a perennial fruit crop? By planting it into the ground. The soil. That is where it all starts.
Sometimes we take soil for granted. But, as many fruit growers have discovered the hard way, not all soil is created equal. And as we approach the end of the first decade of this century, we do so with new tools to look at soils and a growing desire to maintain a quality production site so that soil quality becomes part of the equation.
Although cover crops are far from a new issue in fruit and vine systems, with increasing fertilizer prices (especially nitrogen) and a desire to build up soil organic matter, cover crop management strategies continue to evolve. Legumes have shown promise as inter-row crops in both orchards and juice grape vineyards for supplying nitrogen for both conventional and organic systems. A question that will continue to arise is whether or not letting the legumes make nitrogen for your fruit crop is cost effective. A recent economic assessment of this question in juice grapes indicated that, based on material costs alone, legume nitrogen is less expensive, but once operational practices are added in, probably not. But what this does not consider is the effect on the soil. Organic matter, that universal panacea, can help build long-term soil moisture-holding capacity in low-moisture-holding soils, and can help improve water infiltration and drainage in heavy-textured sites. A cost benefit that reminds us that organic matter can be more than just a nutrient, and cover crops are a tool that can help build system quality.
A tool that literally came on-line at the beginning of the twenty-first century that is especially useful for growers interested in site assessment is the Natural Resource Conservation Services Web Soil Survey, on-line at http://websoilsurvey. nrcs.usda.gov/app/. This is a tool that allows you to get up-to-date soil-survey information and soil-specific data such as water-holding capacity and CEC (cation exchange capacity) on-line. While a computer program to assess a site will never replace on-the-ground assessment or soil and water sample collection and analysis, it is a great tool to get a sneak preview of a site and some exploratory details from the computer-eye view.
Perhaps from a soil and nutrient management perspective, one of the interesting challenges that lies ahead in the fruit industry is sorting our water and nutrient management for ever-evolving orchard and vineyard architectures. Certainly research has shown that high-density apple orchards require a different system of soil management than conventional systems. This begs the question of what will be needed to assure that the nutritional needs of a UFO (Upright Fruiting Offshoot) cherry orchard might be. And while vineyard between-row spacing
may not shrink because of equipment limitations, spacing between plants in Concord and wine grape vineyards seem to be going in opposite directions, which will influence where and when nutrients need to be provided.
So, as the 2000s turn into the 2010s, changes in soil management practices continue to come our way. Look for approaches to balance conventional nutrient supplies with those that build soil quality, for responses to changing canopy architecture, and, as always, issues
of choosing and maintaining quality soil for grape and tree fruit production.
This issue of Good Fruit Grower focuses on the very foundation of our fruit industry: the soils and nutrients that sustain the plants that sustain us. Enjoy it.