Apple grower pg 33-35

COVER CROPPING

Orchard ground should be cover-cropped prior to planting. Ideally, two or even three growing seasons are invested in building up the soil with the understanding that tillage access will never be as good once the trees get planted. Sod is turned the Wrst spring and planted to the Wrst of two buckwheat smother crops. Lime and rock phosphate are best incorporated at the start (if needed) to sweeten the microbial decomposition process. Interplant winter rye with hairy vetch in September to combine the nitrogen Wxation of a legume and the organic bulk of the rye root mass. Red clover interplanted with oats oVers a similar two-bit gain. Green manure options can include bulky Sudan grass, deep-rooted alfalfa, and Hardin soybeans. Choose what works best in your region to most ben-eWt your particular soil type. Most clovers and -alfalfa require a full year’s growth to get the maximum beneWt of added nitrogen.

A basic turf of -orchard grass and Dutch white clover can be established during the year of tree planting if no further row cropping is envisioned.

The cultivated orchards of our great-grandparents were put into a cover crop late in the summer to protect the soil over the winter and renew organic matter. The spring harrowing was essentially a “composting in place” that allowed for aerobic decomposition in the top several inches of disced earth. The fruit trees had no immediate competition during the peak of the growing season for soil nutrients or moisture. Additional cultivations after petal fall kept weeds from taking hold. The planting of a summer cover would be delayed in a dry year to reserve soil moisture for the sizing fruit. But not for too long. The growth of the cover crop helped check tree growth and thus hasten winter hardening.

I like the ideal of maximum soil preparation as much as anyone.

These immediate edges can be worked for a year or two while the trees are small. Annual -nitrogen-Wxers like Weld peas or soybeans lead into a later sowing of oats. Some tree feeder roots may initially get harrowed in the cover crop zone, but the gain in organic matter may justify the eVort. The in-row strip between trees grows to winter rye and self-seeded buckwheat, but wildXowers and other grasses eventually gain the stronger foothold. Any quackgrass that survives year one can be a nuisance around the gravel mulch base that surrounds the young trees, mandating hand-hoeing and/or Xame weeding. Gravity-fed irrigation lines ensure our young trees get enough moisture despite the surrounding growth.

Green manure crops should be incorporated into the soil while still green and succulent. Clovers can Wx up to 150 to 200 pounds of nitrogen per acre when properly managed. Grasses are better at increasing soil organic matter, primarily due to their high lignin content and Wbrous root systems.

Pathogenic fungi can be suppressed by disking in a green manure: the high nitrogen content results in rapid decomposition, which in turn stimulates germination of dormant spores of the pathogen. Since the trees are not yet planted, the germinated spores, having no food source, get attacked by other microbes. Annual legumes grown alongside the tree row should not be directly disked in green in late summer, as the release of nitrogen may delay hardening oV. Mow the legume crop to lie in place, wait a few days, then sow a grass-type cover into the dried green mulch. A biennial legume interspersed with a scattering of oats could be mowed but then left to grow through the fall for shallow incorporation the following spring. The nitrogen boost would come when needed, the winter-killed oats would improve tilth, and the now open ground could be left rough until the summer planting of the next protective cover.