Pepitas de Ajo: permanent ground cover in garlic production
Without permanent live cover, wind erosion, soil compaction, and nitrogen loss will lead to lower and poorer garlic yields. By using gama grass and perennial lespedeza as a low-growing, low water-use, non-invasive, permanent cover in the garlic field, soil structure and stability will be improved and garlic yields should increase. The lespedeza and gama grass have potential as a cover crop as well as being a good forage in a pasture/vegetable system.
In this project, the field will be planted in a split-plot experimental design with treatments of gama grass, lespedeza, a mixture of gama grass and lespedeza, and a control plot with no cover. The field will be further separated into grazed and non-grazed sections. Each treatment will have 6 replications. Before preparation for garlic planting, a sample of soil nitrogen will be taken for all plots. Garlic yields will be measured in all treatments. The grama grass and pre-inoculated lespedeza will be planted after garlic harvest. It will be watered until established. The experiment will be replicated for two years.
Samples of plant nitrogen and samples for dry matter analyses will be taken from the plots. Plant nitrogen levels will help make a determination of the protein value of the lespedeza and the grama grass for grazing. The nitrogen levels of the planted treatments can also be compared with soil levels of nitrogen in all four treatments. In addition all plots will be measured for compaction with a soil penetrometer. Wind erosion will be quantified using Natural Resource Conservation Service guidelines.