GRASS CULTIVATION.

New Zealand Herald, Volume LXVI, Issue 20426, 30 November 1929, Page 22

GRASS CULTIVATION.

TESTS AT ROTHAMSTED.

GRAZING TRIALS UiNCONVINCING

Experiments in the cultivation and feeding value of grass wijre carried out as usual during the yeaff 1927-28, at the Rothamsted Experimental Station. Grass presents special problems, says the annual report of the station, because it is not a single crop but a Mixture, the members of which are competing with one another. Further, the value <of grass is not sufficiently expressed by its weight; it depends not only on the kind of plant but on the way tho plant grows, whether leafy or stemmy.

Two qualities arte important to the farmer; palatabilitjy and feeding value. Palatibility is testeid in the Woburn experiments in Broadmead, where grass is treat with lime, basic slag, superphosphate, potassium salts, on separate unfenced plots, all of which are then grazed by animals free to wander where they will. They qpngregate on the most palatable herbage and leave the rest; they choose always the plots treated with lime and phosphate. Feeding value is tested at Rothajnsted; the plots are fenced in and the animals are given no option as to wh«re they shall go. They are weighed each fortnight.

Skilful and Close Grazing. The results afjain show the value of phosphate?, especially in the form of basic slag of high solubility; within certain limits they show that a 2 per cent, solution of citric acvid is a useful agent for estimating agricultural value, though others are being tested with promising results. The experiments have emphasised the importance of skilful and close grazing in the management of grassland; this is oven more important than manuring and findeed, some of the records show that a properly manured pasture badly grazed may be worse than one left unmanured.

Grazing experiments are, however, the most unsatisfactory of all field trials, states the report. Uhey are crude and liable to gross error.. They answer well enough to show strikingly obvious differences and, with pooper precautions to ensure success, they can make effective demonstrations, but; they give little or no information txqyond ' What a competent grazier could deduce on mere inspection of the herbfjge.. .The variations in the individual animal, the marked difference in results, according as one more or one less is put pip a particular plot, and the impossibility 'of allowing for the maintenance requirements, complicate a problem already .rendered . difficult by the variations in, the land itself. The station is endeavouring, during the present season, to improve the method so as to make it yield mare 'useful results. The mowing method uSe'd' successfully in certain investigations• is -a4so ■ being tested. Manuring of- Hay Land.

Much clearer. results are obtained in tho manuring of hay land. Experiments on this subject were begun in 1856 on grass which even then was very old, knd they havia been continued ever since, the land being hayed every year, two crops being taken without grazing. The results show. the importance of potassic and pholsphatic fertilisers for ensuring quality, and of nitrogenous fertilisers for giving bulk and. early growth . The effect of slag depends on its solubility; slags of 60 per cent., or more solubility, in the -2 per cent. - citric acid solution are more effective than those of 40 per cent, or less.