It’s Time to Assess the Best Time to Irrigate Cotton

Young cotton plants are basking in the warm, sunny weather.

Field scout Damien Jelen reports everything is progressing well as growers prepare for the first irrigation after planting. But UC experts caution growers about opening the water spout earlier than usual. 

Bob Hutmacher, a local UC Cooperative Extension specialist, says it’s tempting to do so because of the increased availability of water following the drought-busting winter. Resist the temptation, though, he says.

UCCE's Bob Hutmacher.

His reasoning: If growers had pretty good moisture for planting and early root development in the upper 18 to 24 inches of the soil, it is better to wait because you will end up cooling the soil. That could slow growth.

Hutmacher also says early irrigation also can heighten the risk of plant loss because of seedling diseases. The time to water is before planting, which leachesout the salt built up. Growers that didn’t do that can make it up by adding more water and making an earlier first in-season irrigation this month or in June.

Cotton plants are quite salt tolerant. Salt accumulation can wind up affecting plant growth and yields.

The first post-planting cotton irrigation will be soon.

If well water with mild to moderate salinity levels was used to irrigate on previous crops in the area where cotton was planted this season, then growers should consider collecting soil samples to determine salinity levels in the upper root zone.

This season’sheavy rains are likely to prompt growers to do more weed management in the fields, Hutmacher says. The increase in weeds coupled with fewer fallow fields may translate into more complicated pest management issues. Early season thrips and lygus could lead to increased crop damage in 2017.

Almonds are getting big.

Meanwhile in almonds, field scout Jenna Mayfield reports no significant pest concerns orchards. She says almonds are larger than normal for this time of year. That’s a good sign so far. Of course, there’s still a long way to go before harvest.

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