Studies on sod culture of orchards. II

Effect of successive cutting of grass on conservation of soil moisture and available nitrogen

Abstract

In 1953, the experiments were conducted in two years old sod blocks of orchard grass and Ladino clover, to study what sort of practise of cutting were effective on conservation of soil moisture and available nitrogen (NH₄+N0₃), and following results were obtained:
1. Frequent grass cuttings improved soil mois-ture conservation under the sod from surface to deep layers, but rare cutting effected only on the surface and kept deep layer as dry as in untreated sod plots.
2. Frequent grass cuttings reduced root growth of the sod and consequently it seemed to be effec-tive on reduction of soil moisture consumption by grass.
3. Soil moisture reduction under orchard grass sod were significant in earlier season, while under
Ladino clover sod it appeared later. The effect of cutting treatment was more remarkable under the former than the latter. The fact shows that orchard grass sod are able to be managed more easily than Ladino clover to keep moderate soil moisture con-tent.
4. Grass cutting may be rather effective on the conservation of available soil nitrogen, but not so clearly as of soil moisture, for available nitrogen in the soil increased more or less about ten days after cutting. But when fruit trees suffer from shortage of nitrogen severely, being absorbed by grass, application of additional fertilizers or leaf sprays of urea may be desirable.
5. Orchard grass sod may need more careful fertilizer management than Ladino clover sod, for the former can not fix air nitrogen by itself.