One Thousand Questions in California Agriculture Answered

by Edward J. Wickson

Do you consider straw good to plow under for humus, and which kind, wheat, oat, or barley straw, is best?

Straw, by its decay in the soil, produces humus and, therefore acts in the same way just as does the decay of other forms of vegetation. As, however, straw is less easily decomposed than fresh vegetation, it is less valuable and may be troublesome by acquiring a greater amount of moisture by interfering with cultivation or by tending to dry out the soil to the injury of other plants. If the soil is heavy and moisture abundant, straw may be desirable, while in the case of a light soil and scant moisture, may be injurious. There is no particular difference in the straw of the different grains from this point of view.

The Best Legume for Cover Crop.

What would you advise to sow as a crop to plow under? When should it be sowed, and when plowed under?

The best crop for green-manuring in any locality is the one which will make the best growth when surplus moisture is available for it, and when its growth can be undertaken with least interference with irrigation, cultivation and other orchard operation. Generally in California, such a crop can be most conveniently grown during the rainy season, but in some parts of the State where irrigation water is available, a summer growth can be procured with very satisfactory results; so that we are now growing in California both wintergrowing legumes, like field peas, vetches, burr clover, etc., which are hardy enough to grow in spite of the light frosts which may prevail, and are also growing summer legumes which thrive under high temperature, like cowpeas and other members of the bean family, and for which water can be spared without injury to the fruit trees which share the application of the land with them. The plants which are worth trying are burr clover, common or Oregon vetch, Canadian field pea, and the common California or Niles pea. Whichever one of these makes the best winter growth so that it can be plowed under early in the spring, say in February or March, while there is still plenty of moisture in the soil for its decay, without robbing the trees or rendering the soil difficult of summer cultivation, is the plant for you to use largely. All these plants should be sown in California valleys and foothills, as soon as there is moisture enough from rainfall to warrant you in believing they will catch and continue to grow. If the land is light they can be put in with a cultivator and plowed under deeply in the spring, as stated. If the land is heavy, probably a shallow plowing would be better to begin with.

Cowpeas for Cover Crop.

I planted cowpeas between peach trees which I have kept irrigated; when should they be plowed under?

Cowpeas will be killed by frost in most places and should, therefore, be plowed in this fall whenever you have a large growth of green stuff and the ground gets moist enough so that the trees will not be endangered by drying out of the soil, which is likely to occur after plowing in coarse material, unless the soil is kept moist by rain or otherwise.

Garden Peas for Green Manure.

Would it be possible to plant the Yorkshire Hero pea in on orange grove as late as December 25 and get a crop from the peas? Would this pea add much to the fertility of the soil?