El Nino Dry-Spell Cover-Crop Management
Keep your established cover crop alive through the dry spell rather than sowing new seed into dry soil. In an El Nino year, an existing legume cover protects the interrow from baking, holds soil moisture, and shades out drought-tolerant weeds. New sowing usually fails on dry ground, so dry-spell management is mostly about protecting what you already have and timing fresh seed to the rains.
This article covers how a cover crop helps in drought, how to manage it through the dry months, and when to sow if you start with bare ground.
How does a cover crop help during an El Nino dry spell?
A living legume cover shades the soil surface, lowers surface temperature, and slows moisture loss from the interrow. Bare interrow soil under a Philippine dry-season sun heats and cracks, loses moisture, and lets drought-hardy weeds take over. A legume cover such as Pueraria javanica (Neustanthus phaseoloides) or Centrosema pubescens keeps a canopy over the soil, which holds moisture in the topsoil longer and keeps the ground cooler for the crop roots underneath. The cover also keeps fixing nitrogen and adds organic matter that improves how the soil holds water over time.
Note: Pueraria javanica is a managed tropical legume, not the invasive kudzu (Pueraria montana).
The trade-off is that a cover crop also uses water. In a severe drought the cover competes with the main crop for soil moisture, so management is about balancing protection against that competition.
How do I manage cover crops through the dry months?
Reduce competition by slashing the cover back, keep a mulch layer on the soil, and protect the palm or tree circles. As the dry spell deepens, slash the legume cover to a low height rather than removing it. The slashed material becomes a surface mulch that keeps shading and protecting the soil while the cut-back cover draws less water. Keep the mulch in the interrow and keep the immediate circle around each palm or tree clear so the crop is not competing with the cover for the little moisture there is.
Avoid heavy pruning that strips the soil bare, which undoes the moisture protection. Aim for a low, living-plus-mulch cover that holds the ground without drinking the block dry.
Which species hold up best in a dry spell?
Choose deep-rooting, drought-tolerant legumes already established before the dry season arrives. Pueraria javanica and Centrosema pubescens are both used as persistent covers in the tropics and tolerate dry periods once established. Calopogonium caeruleum is valued for shade tolerance and persistence under mature canopy. The key is that these are established before the drought, since dry soil will not carry a new sowing. Exact drought-survival thresholds vary by species, soil, and site.
When should I sow if my interrow is already bare?
Sow with the return of reliable rain, not during the dry spell. Seed broadcast onto dry soil germinates poorly or dies after a false start when a single shower is followed by more dry weather. Hold your seed, prepare the ground, and broadcast at the start of the wet season when soil moisture will carry the seedlings through establishment. Sowing into the first dependable rains gives the fastest closed cover and the best nitrogen fixation for the year.
FAQ
Will a cover crop steal water from my main crop in a drought? It can. A cover crop uses water, so in a severe dry spell slash it back to a low mulch to cut its water use while keeping the soil shaded, and keep the crop circles clear of cover.
Can I sow cover crops during the dry season? No. Dry soil will not carry a new sowing. Hold the seed and broadcast at the return of reliable rain so the seedlings establish on moisture.
Does slashing kill the cover crop? No. Slashing to a low height sets the legume back but it regrows after the rains. The cut material becomes a protective mulch that keeps shading the soil through the dry spell.
Plan your dry-season cover
Tell us your crop, region, and whether your cover is established or bare, and we will recommend species and a dry-spell management plan. Request a quote on WhatsApp at +60 17-237 4058 or through info@kudzuseeds.com.
Sources
- Tropical Forages, Neustanthus phaseoloides (Pueraria javanica drought and persistence): https://www.tropicalforages.info/text/entities/neustanthus_phaseoloides.htm
