MINERAL CONTENT OF PASTURES.

New Zealand Journal of Agriculture, Volume XXXVI, Issue 2, 20 February 1928, Page 75

MINERAL CONTENT OF PASTURES.

PROGRESS OF THE NEW ZEALAND INVESTIGATION.

( Continued.)

B. C. Aston,

F.N.Z.Inst., Chief Chemist, Department of Agriculture.

The first article of this series gave the results of analyses of certain red-clover • samples taken from differing types of pumice sands and loams in Rotorua County (see last month’s Journal, p. 22). In the present article the samples of white clovers and cocksfoots taken from the same lands are given. In order to save space and to 'enable the results to be seen at a glance the figures have been averaged, and the averages given in the first article for red clovers are assembled and repeated. WHITE CLOVERS. In white clover there is no tendency to produce a woody stem, and one would expect in this species less variation in the chemical composition due to the stage of growth than would occur in the other species (red clover) or in the grass (cocksfoot). There is, however, greater difficulty in securing samples of white clover free from earthy contamination, due to the lower-growing habit of the plant, than is the case with the taller-growing red clover. Some analyses of samples from external soil provinces are inserted for comparison. The analyses do not show that there is any considerable increase in the phosphoric-acid content due to artificial manuring with phosphates, but this may be owing to the meagre amount of manuring practised in the district under review. In the case of calcium oxide (lime) there appear to be important differences. In the samples from external loams (Gisborne) the lime content is higher than is usually found in the Rotorua lands, and in the case of the Himitangi land, which is very low in phosphoric acid and high in calcium carbonate, the white clover shows a similar correspondence in its content of those constituents. The Gisborne and Otago Central (Ranfurly) lands may be reckoned as naturally among the richest in New Zealand, and the samples from these districts are high in phosphoric acid and calcium. As shown in the previous article, the amount of iron found in the samples from the coarser types of soil the fine gravelly sand of Kaharoa and the coarse sand of Ngongotaha —is much lower than in

the samples collected from the finer soils — the sandy loam of Oturoa and the calcareous sandy loam of Te Ngae. Generally speaking, the amounts of phosphoric acid are similar in samples from all types of soils, but the calcium content varies more widely. The results of analyses have again been classified under the headings of “ contaminated ” and “ uncontaminated ” samples.

There appears to be this anomaly in the analysis of pasture plants from the Rotorua and adjoining counties : that although the lakeside paddocks at Ngongotaha, which are a recognized sanatorium for bushsick stock, are composed of coarse sandy soils, they are looked upon as absolutely healthy for stock, and there is no reason to doubt this local •tradition. The iron, phosphoric acid,, and .calcium contents of the pasture plants are apparently little different from those of the most unhealthy country. There is one element, however, which appears to be present in abnormally high amount in the lakeside pastures, and that is manganese. The writer drew attention to. the possible influence of manganese compounds on plant-life in 1912 (this Journal, Vol. 5, p. 123), and wrote : “ The effect of manganese compounds on plant-life is one of the puzzles of agricultural chemistry. Analyses of the affected soils and grass from them have shown that manganese is present in amounts greater than in ordinary soils and grasses. It may be detected in aqueous extract of the soil filtered through porcelain and in citric-acid extracts (‘ available plant food’) of pumice soils in very variable amounts.” Manganese—there is ample evidence from other countries—may be either injurious or beneficial to the growth of plants. In the case of the unhealthy pumice lands it may be positively beneficial. Thus in the white - clover and cocksfoot samples analysed the averages for manganese and iron are as follows :—

White- Clovers.

Mn 3 O 4 . Fe 2 O 3 . Ngongotaha (lakeside 0-020 o-oio only) Te Ngae . . .. 0-009 0-017

' Mn 3 O 4 . FeO 3 . Oturoa . . . . 0-015 0-017 Kapakapa .. .. o-on 0-012

Cocksfoots.

Mn 3 O 4 . FesOg. Ngongotaha (lakeside 0-057 0-014 only) Te Ngae . . .. 0-021 0-017 External lands— Karori .. " . . 0-015 0-029 Te Kauwhata . . 0-027 0-034

Mn 3 O 4 . Fe2O 3 . Oturoa . . .. 0-028 0-017 Kaharoa . . . . 0-048 0-014 Mamaku . . . . 0-034 0-014 Kapakapa ... ’ . . 0-030 o 013

In the red clovers from the lakeside there are only contaminated samples, but an inspection of the figures will show that they tend in the same directions as do those of the uncontaminated samples of white clover and cocksfoot. It therefore, appears that the manganese by its action in the digestive tract may be enabling the small amount of iron in the pasture to be economized by the animal. With this exception, it would appear that, as with the red clovers, the healthier the land the more iron there is to be found in the white clover growing upon it.

The small amount of improvement in the phosphate content of the white clover manured with phosphate is a matter which calls for attention. It may be that the grasses are the pasture components which are more extensively altered in their mineral content by manuring, and that the clovers are always of fairly uniform composition .in this respect. The matter will be more suitably discussed when the analyses of the cocksfoot samples are considered. It will be observed that as yet no attempt has been made to lay •down definite standards to distinguish contaminated from uncontaminated samples, and the writer considers it unwise to fix such ■standards until the results of a larger number of samples have been accumulated over more than one season, and, if possible, from a series •of soil types and soil provinces. At present each sample is judged on its merits. The amount of silica will certainly need to be determined separately for the grasses and for the clovers, as there is no doubt that this constituent is taken up in greatly differing amounts under normal conditions by the two families Graminece and Legwninosce. With regard' to .alumina, this may also be taken up in very different amounts by these two families. In water cultures McLean and Gilbert {Soil Science, Sept., 1927, Vol. 24, p. 163) found that rye-plants absorbed 0-05 per •cent, aluminium, which is equivalent to 0-95 per cent, aluminium oxide (A 1 2 0 3 This is possibly higher than usual, as the cocksfoots grown in soil (not water), which are considered uncontaminated in these articles, have not a higher alumina content than 0-05 per cent. A1 2 O 3 approximately. Stoklasa considers that plants in moist places absorb aluminium more freely than do plants ordinarily. This authority found o-oi per cent. A1 2 O 3 in the above-ground portion of cocksfoot in dry situations and 0-016 per cent, in wet situations {Jour. Agric. Science, Vol. 16, p. 337). Some work of ' McCarrison {lnd. Jour. Med. Research, No. 14, 1927, p. 641) opens up a new field for investigation. It appears that rats fed on rice and wheat, when an ad libitum basal diet was also given, showed differences which were in part attributed to the greater manganese content of the wheat, which contained an amount four times • greater than that of the rice. This was tested by adding manganese to the rations. The conclusion appears to be justified that concentrations of manganese of the higher order (1 in 12,600 of food) were harmful to the animal organism, while concentrations of the lower order (1 in 617,700) were beneficial ; and since a diet containing a fair proportion of whole wheat provides a concentration of the lower order, it may be concluded that the growth-promoting properties of whole wheat are in part due to the content of manganese in this cereal.* There are now several biochemists studying the influence of manganese in the diet on animal - growth, and it affords a most fascinating field for study. COCKSFOOTS. The great difference in the chemical composition of the ash of grasses compared with clovers is now seen to be the silica content, which is very high in the grasses, and almost absent in the clovers, * A possible explanation of the fact that in the feeding of penned fowls wheat cannot be substituted by many other obtainable foods may be the beneficial -influence of manganese in the wheat.

except when present as an earthy contamination. There is also the difference that there is much less phosphoric acid and lime in a grass than in a clover. This refers to the immature plant as eaten by stock from unmanured land. The average phosphoric acid in the cocksfoot samples from the pumice soil-province unmanured lands is from 0-46 to 0-65 per cent., whereas in paddocks top-dressed with phosphate the average phosphoric acid content of the samples is 0-87 per cent.

This seems to indicate that greater change in the composition of the grass than in that of the clover of a pasture is effected by manuring. As with the clovers, the iron content of the samples is always greater, with one exception, on the healthy than on the unhealthy land.

The outstanding results of the analyses of fodder plants from the pumice lands is that the percentage of iron in the plants is always much lower on the unmanured lands than on similar lands from the external districts, where the plants are not growing on soils recently derived from rhyolite. In the case of silica, uncontaminated samples seem to be higher in this constituent than plants growing in nonpumice soils. SUMMARY. There seems to be a very large area of country producing in the untreated pasture red and white clover and cocksfoot-grass having a very low iron content compared with outside country on soil not recently derived from rhyolite. This information is gained from practical experience of samples collected and analysed from the respective districts. The literature which is available, and which gives analyses of the plant staples mentioned grown in. other countries, also supports the contention of abnormally low iron content of the pumiceland pasture staples. In comparing the analyses of the samples from healthy and unhealthy country in Rotorua County from land not artificially dressed with fertilizers, only one exception is found to the rule that the high iron content is found in healthier country and low iron content in unhealthier country. • In regard to. this exception it

is suggested that some secondary influence, probably manganese, is rendering the herbage healthy.

In Table 6 the three staples are arranged according to the localities whence they came, in the order of relative freedom from deficiency disease (iron-starvation), beginning with the least healthy and ending with the most healthy. In order to avoid decimals the results (averages) are stated in parts per' million. In the cases both of the white clovers and the cocksfoots there is ample evidence that from artificial manuring with phosphate alone, and with phosphate and iron, the iron content of the plants has been greatly increased. (To be continued.)

Note. —Of these, the Te Ngae, Oturoa, and Ngongotaha lakeside lands are undoubtedly free from the trouble, and Kapakapa is the most “ bush sick ” of all lands.

Note. —Te Kauwhata soil contains much maganese

Note, the to pure I .

* Position anomalous, see explanation.

Number of Samples averaged. Ash. co SiO. 2 O. 3 O. CaO. MgO. Mn 3 N. O. of Soil. Locality. 1 and. Unmanured. ... 7 9'4° i-97 O-II 0*011 0-63 1-92 Unco 0-70 ntaminated ani 0-012 3-43 1 Unmc 0-020 mured. Sandy silt and coarser Mamaku, Kaharoa, Ngongotaha ■ 1*92 0*70 0*012 3*43 • 0*020 Sandy silt and coarser Mamaku, Kaharoa,. Ngongotaha Mountain. 3 8-90 i-77 0-18 0-016 0'73 i-99 o-75 0-008 3-98 0-025 Coarse Mountain. Ngongotaha streamside. Ngongotaha streamside. I 10-69 1-84 0-21 0-021 o-88 2-01 0-70 0-012 4'74 0-030 Calcareous loam sandy Te , Ngae Oturoa. 4 g-68 i-66 0-15 0-014 0'74 1-76 o-59 0-015 2-96 0-022 Sandy Oturoa. Uncontaminated and Manured. 3 10'21 0-13 4 o*8i 2-62 Uncontaminaled and Manured. 0-82 0-014 ■ 4*56 0-033 Sandy silt . . Mamaku. 0*82 0*014 4'56 0'033 Sandy silt ■ ■ Mamaku. 2 0-16 0-013 0-83 1*97 0-016 Reporoa. ■ io-o9 0-16 0-017 0-79 2-06 0-009 0-029 Silt Turakina. Contaminated and Unmanured, 3 g*22 I 0-51 O*O2 4 o-79 i-37 Con o*93 . 0*016 0*042 Fine gravelly sand . . , Kaharoa and Kapakapa. 0'93 ciminal 0-016 id and Unmanured. 0-042 | Fine gravelly sand Kaharoa and Kapakapa. 7 9'56 1-63 0-25 0-016 o-8i 1-76 o-57 0-015 4’23 0-051 Sandy Mamaku’. . 3 10*31 0-42 0-019 0-87 1-71 o-8o 0-033 0-036 Coarse lakeside. 3 10*49 I-S 5 0-52 0-027 o-77 2-05 0-67 0-015 loam sandy Te Road. 2 I2-o8 2-69 0-18 0-019 o-68 2*35 o-74 0-017 0-044 Sandy loam Oturoa.

Table 3.- Analyses of Red Clovers (aceraged). The figures are percentages on material dried to constant weight on water bath.

Number , of Samples Ash. co 2 . 1 SiO,. j Fe 2 O 3 . P2O5. CaO. MgO. , Mn 3 0i. n. i . 1 Fusion A1 2 O 3 . A1 2 O 3 . Type of Soil. Locality. averaged. 1 I L — ■ - Uncontaminated and Unmanured. Ash. co 2 . SiO 2 . 1 Fe 2 O 3 .1' P2O5; CaO. MgO. Mn 3 0<. N. Fusion AI2O3. A1 2 O 3 . i Type of Soil. Locality. Uncontaminated and Unmanured. 3 4 5 8 7 10-94 10-19 8-72 1-50 i-99 1’79 1-28 0-16 0-21 0-23 019 0-012 0-017 0-017 0-010 0-78 0-69 0-85 o-8o ■ 1-98 -66 i i-75 i’3° | o-54 o-6o 0-50 0-62 o-oii 0-009 0-015 0-020 4-26 ' 5 4’ 0-017 0-021 0-021 Fine gravelly sand Calcareous sandy loam Sandy loam Coarse sand Kapakapa. Road, Kaharoa. Te Ngae. Oturoa. Ngongotaha lakeside. ... Fine gravelly sand Calcareous sandy loam Sandy loam . ... Coarse sand Kapakapa Road, Kaharoa. Te Ngae. Oturoa. Ngongotaha lakeside. Manured. and U d Manured. 4 9-49 1-29 0-15 0-018 1-09 2-06 0-52 0-019 0-013 0-026 Sandy . Demonstration Farm. 3 9'75 0-22 0-021 0-85 i-77 o-66 0-013 0-013 •• . Sandy silt . . Rotorua and Ngongotaha • • and Contaminated 0-013 Manured. Sandy silt . . Rotorua and Ngongotaha Contaminated and Manured. 7 9-97 5 0-37 0-026 o-93 i-8o 0-51 o-oio 0-045 pumice Rotorua, Oturoa, Kaingaroa 1 a, Ngongotaha. Plains, igotaha. 3 3 9-48 11-38 I-OI 1-70 0-36 o-39 0-028 0-033 I-IO o-77 1-50 1 0-67 o-6o 0-014 0-045 0-046 Sandy loam Calcareous sandy Omanawa. Te 4 Pahiatua 4 11-08 i-47 0-41 0-034 o-86 1-52 0-73 0-009 0-034 samples). and Contaminated Unmanured. Ngongotaha. Oturoa. ' . Mamaku. Te Ngae and Wairoa. Kapakapa Road, Kaharoa and Te Pu. 8 T ‘77 0-31 0-028 0-84 i-88 0-64 0-030 4-25 0-028 0-051 Coarse sand Ngongotaha. 3 6 4 6 10- 9-9-38 II-OI 11- 10- 5 i5 - 9-98 i’49 1-56 1-41 i-43 0-29 0-27 0’45 o-3° 0-020 0-029 0-027 0-019 0-76 I-OI 0-96 0-91 1-71 1-90 i-57 1-90 0-50 o-57 0-67 o-6i 0-016 0-018 0-009 o-oi 1 0-051 0-036 0-025 ■; 0-057 Sandy loam Sandy silt . . Fine gravelly sand Oturoa. Mamaku. Te Ngae and Wairoa. Kapakapa Road, Kaharoa and Te Pn. 9’98 i’77 1’49 1’56 1-41 1’43. 0-31 0-29 0-27 0’45 0-30 0-028 0-020 0-029 0-027 0-019 0-84 0-76 I-OI 0-96 0-91 i-88 1-71 1-90 i’57 1-90 0-64 0-50 0’57 0-67 o-6i 0-030 o-pi6 o-6i8 0-009 o-oii 4’25 0-028 0-051 0-036 0-025 O-O5I 0-057 Coa.rse sand Sandy loam . . Sandy silt . . Fine gravelly sand 22 12-18 1-65 0’43 o-86 0-028 0-032 1-05 1-03 2-26 2-01 0-52 0*020 0-033 0-072 Loam Silt 3 Gisborne. l Exter Karon. i f samples. Himitangi.* J 8 i i 10-98 12-15 9-22 i-55 i-88 i-54 o-53 o-33 0-19 0-057 0-037 0-020 0-91 0-89 i o-6i i-68 2-o-6i o-59 0-58 0-006 0-009 0-012 ; 3-36 4’29 0-072 0-005 0-133 0-034 0-041 Loam Sandy loam Dune coarse sand | Karori. Ohakune. Himitangi.* 1 — _ 0’53 o-33 0-19 0-057 0-037 0-020 0-91 0-89 o-6i i-68 2-o-6i 0’59 0-58 0-006 0-009 0-012 3’36 4’29 0-072 0-005 O’i33 0-034 0-041 Loam . . Sandy loam , . . Dune coarse sand 1

Table 4.- Analyses of White Clovers (averaged.) The figures are percentages on material dried to constant weight on water bath.

Number jf Samples averaged. Ash. SiO. FeO3. P2O5. CaO. MgO. M113O4. N. Fusion OAl 3 . Locality. • Type of Soil. Locality. A1 2 O 3 . Type of Soil. 8 10-72 2'55 0-014 0-46 0-50 0'43 Uncontaminat I 0-034 ed Unmeet 0-043 wred. Fine gravelly sand Te Pu, Kaharoa, Kapakapa. 0-043 vured. Fine gravelly sand Te Pu, Kaharoa, Kapakapa. II 10-27 2-26 0-014 0-50 0-46 0-40 0-034. silt . Sandy Mamaku. 3 10-90 2-36 0-014 0-65 o-44 0-41 0-042 Coarse lakeside stream- Ngongotaha. 7 ii'3o 2-91 0-019 o-6i 0-52 o-53 0-028 Sandy loam side. Oturoa. . . . Sandy loam side. Oturoa. 6 10-83 3-42 0-017 o-53 o-43 0-021 0-030 0-019 Calcareous sandy Road. I 10-88 00 S’ 0-034 0-38 0-42 0-027 0-028 Clay loam Te Kauwhata\External dis- • • Clay loam Te dis3 jo-74 1-82 0-029 0-70 0-40 0-48 0-015 0-034 Loam ... Karori / tricts. 0-028 0-034 Loam Karori tricts. TO 11'12 2-59 0-020 0-87 0-64 0-46 U | Various 0-031 | Omanawa, Rotorua. Kaharoa, I .13-16 5-3° 0-042 °-44 0-46 Cont 0-016 minute d 0-027 Unman 0-061 A.red. sandy Te (washed). I 13’54 5’4° 0-046 °-47 0-41 0-017 0-145 0-095 loam sandy Te 4 10-39 2-94 0-012 0-50 o-33 0-026 Sandy silt . but and Tauranga 2 . 12-15 2-53 0-021 0-87. o-73 0-46 0-023 0-052 0-082 Sandy and and Road. Kapakapa 5 10-90 3-26 0-017 0-62 0-62 0-41 0-027 Coarse sand ... lakeside Ngongotaha 4 12-90 3-16 0-017 0-50 o-8o o-44 Calcareous Island. Te I 14-50 3-04 0-074 3 o-47 0-023 0-045 0-122 Loam Karori (external

Table 5.- Analyses of Cocksfoots (averaged). The figures are percentages on material dried to constant weight on water bath.

Type of Soil. Red Clovers. White Clovers. Cocksfoots. Number of Samples. Fe 2 O 3 . (P.p.M.). Number of Samples. Fe2O 3 (P.p.M.). Number of Samples. Fe 2 O 3 (P.p'.M.). Fine gravelly sand, unhealthy for all 7 I IO 3 120 8 140 ruminant stock 7> .no 3 120 8 140 Sandy silt, unhealthy for all ruminant 11 140 stock 11 140 Sandy loam, healthy for cattle after 4 I 4 O 5 170 7 190 top-dressing 4 140 ' 5 I70 7 190 Coarse sand, healthy without top3 160 2 100 3 140 dressing* 3 160 2 IOO 3 140 Calcareous sandy loam, perfectly healthy i 210 4 170 6 170 . for sheep and cattle i 210 4 I70 6 170 External district loams, quite healthy 1 200 3 290 External district loams, quite healthy •• 1 •• 34° 1 340

Table 6. —Pasture Staples in Order of Freedom from Deficiency Disease.