Soil& Tillage Research, 19 ( 1991 ) 35!-355 Elsevier Science Publishers B.V., Amsterdam

351

Influence of subsoil compaction on the uptake of 45Ca from the soil profile and on maize yield

Krzysztof Gediga h~sfftute of Soil Science and Cultivation of Plants, Department of Soil Tillage, ~ 5-230 Jelcz-Laskowice

(Poland)

(Accepted for publication 15 March 1990)

ABSTRACT

Gcdiga, K., 199 !. Influence of subsoil compaction on the uptake of 45Ca from the soil profile and on maize yield. Soil Tillage Res., 19:351-355.

The effect of subsoil compaction on maize dry matter content and green tops yield was ~nvestigatcd in a lysimeter experiment. After labelling several layers of the soil profile with 45Ca,, the uptake of this isotope was determined. Maize green tops yield increased and dry matter content decreased with increasing subsoil bulk density. Total uptake of 4SCa had a minimum at 1.55 gcm -3 and was not different for !.45 and 1.70 gcm -3. The concentration of 4SCa in the dry matter was higher at 1.70 g cm -3 than at 1.55 and 1.45 g cm -3, where it was similar.

INTRODUCTION

The production capacity of soils can be improved if in addition to nutrient reserves and water present in the arable layer, subsoil reserves are available to the plants. Measurements of the physical properties of the subsoil show that compacted layers often exist in this part of the soil profile (Coote and Ramsey, 1983). High bulk density of subsoil lay~:rs may be harmful for root growth and root activity, and for crop yield.

Investigations concerned with the influence of many soil factors on plant growth and crop yield mainly apply to the arable layer (Smie~chalski, 1972; Kwasowski et al., 1981 ). Publications concerning the effects of subsoil com- paction on c~c,p gtowth are not numerous (Lu and Edwards, 1985).

The purpose of the present research was to estimate how differentiated compaction of the subsoil influences the uptake ability of the root system and :~'op yieid.

MATERIALS AND METHODS

In 1987. a lysimeter experiment with subsoil compaction was established. Lysimeters 80 cm in diameter and 90 cm deep were filled with the natural

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352

TABLE 1

Bulk density (gcm -3) in the soil profile

K. GEDIGA

Depth Treatment (em)

II III

0-30 1.45 1.45 !.45 30-60 1.45 1.55 1.70 60-90 1.47 1.58 1.73

subsoil profile composed of silty, weakly loamy sand in the 30-90 cm-layer. The arable layer (0-30-cm depth) consisted of pseudo-podsolic soil derived frcm silty, light loamy sand. In the experiment, the following variants of sub- soil compaction in the 30-60-cm layer were compared: non-compacted ( 1.45 gcm -3) and two levels of compaction ( 1.55 and 1.70 g cm-3). In the 0-30- cm layer, the bulk density was 1.45 gcm -3 in all variants (Table 1 ).

The subsoil compaction was obtained by ramming appropriate amounts of subsoil into the lysimeters to fill the profile in the 30-60-cm layer. The var- iants were randomized in seven replications for estimation of the uptake of 4SCa by maize from different depths of the soil profile in 5-cm layers down to 35-cm depth. The application of the calcium isotope 45Ca was performed ac- cording to Hr;nczuk. et a!. ( ,-,~,,,,I o ~ ~ i.e. *he,, soil,; . . . . . . . . . . mass needed to occupy a 5-cm deep layer was treated with 7.5 MBq a~CaCI2 diluted in 100 ml of 0.02 mo! CaC12 carder, and mixed thoroughly with the soil. The ~5Ca uptake was r~. ti- ochemically analysed at six sampling times.

RESULTS AND DISCUSSION

The degree of subsoil compaction influenced maize green tops yield and dry matter content (Table 2). Higher subsoil compaction increased y!telds, but decre:,sed dry matter content. However, these effects are not statist::,cally significant. In the case of oats and winter wheat cultivated under similar com- paction conditions ( 1.57 gem- 3 ), Kozicz ( 1971 ) found several percent yield increase, but a still higher bulk density (1.70 g c m -3) caused yield reduc- tions: in oats 16.3% and in wheat 52.2%.

Results of radiochemical analyses showed that uptake of the isotope 4SCa by maize was highest on non-compacted subsoils and next highest on the most compacted subsoils, where its highest concentration in the dry matter was also found. The plants on lysimeters with intermediate subsoil compaction (1.55 g c m -3) showed the lowest uptake of 45Ca. The influence of subsoil compaction on 45Ca uptake was particularly clear in the deepest layer (30-

SUBSOIL COMPACTION, 4SCa UPTAKE AND YIELD IN MAIZE 353

TABLE 2

Maize green tops yield and dry matter content, and uptake and concentration of 4SCa depending on subsoil compaction ( 30-60-cm depth)

Subsoil Yield per Dr,/matter Total uptake Concentration of 4SCa bulk density iysimeter content of ~-~Ca in the d,~ ,,,,~tler (gem -3 ) (kg) (%, w/w) (kBq) (kBq g - ' ) '

1.45 5.82 27.0 6.52 0.14 i.55 6.26 23.6 6.09 0.14 i .70 6.46 20.7 6.31 O. 16

'LSDo.5=0.011.

' I

E 1 u

q

~..-':~ 1.4s g c m - =

1.55 g cm -~ ~ - : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : . . _ . . . . . . . . . , . . . . . • . . . . . • . . . : . . . . • .

o 20-25 :!!iii!!iiiii!ii!!ii!!ii ~ ] ~ 1.7o g cm-~

i'i

-:. :-: : ; : - : - : : .~. : . : . ! . : . : . : . : . : . : . : . : . :~.~.: .~.~.: . : . : . : . : . : . : . : . : . : . : . : . : . : . : . : . : . : .~:?.*. : . : : . : , : . : . : , : . : . : . : - : , : . : . : . : . : . : - : : : . : . : . : - : . : . : - : - : - : - : . : . ; - : - : - : . : - : - : . :1 ~ ~ : ! : ! :]?!~!??!?!:!!!?!?!?!i!~?i!?i:~!!!i ....... :: ................ 30-35 l]:i:i:]:i:i:]:i:i:i:i:i;-~:i:i:i:i:i:-:]:!:i:i:i:i:i:i:i:i:i:!:!:i:i:i:]:l I I

],,,,l!I1,i~,11,11,11i,,,,l,,,,i ,,ilJ ~' 5 1l[', 15 20 25 38 " . 35

4=Ca uptake (~) Fig. 1. Relative uptake of 45Ca from different depths in the 0-35-cm layer, depending on differ- ences in compaction in the subsoil (30-60-cm depth).

354 K. GEDIGA

35-cm), which already belongs to the subsoil (Fig. 1 ). For non-compacted subsoil, the uptake from that layer constituted 31.5% of the total uptake. However, for subsoil compaction to 1.55 and 1.70 g cm -3, the uptake amounted to only 26.4 and 16.3%, respectively, of the total uptake. In lysi- meter experiments with non-compacted soil, the 25-35-cm layer constituted a considerable part of the total uptake of 45Ca (Hrynczuk et al., 1986). The same tendency was found in this experiment, but higher bulk densities ( !.55 al~d 1.70 g cm -3) decreased the uptake ofa 'Ca fzom the 25-35-cm layer.

In all variants of compaction, the 0-5- and 30-35-cm layers contributed most t,a the total uptake of aSCa. In lysimeters with non-compacted subsoil, these layers contributed as much as 52.4% to the total uptake, in the other treatments the values were 39.3 and 44.9%, respectively. Probably this result is caused by diminished root activity as a consequence of increased bulk den- sity of the subsoil. The smallest differentiation in the 45Ca uptake from 5-cm layers in the 10-30-cm depth was observed in treatments with subsoil com- pacuon to 1.55 g cm -3.

CONCLUSIONS

( 1 ) The effect of subsoil compactio~ wzs especially clear in the uptake of Zhe calcium isotope 45Ca from the 30-35-cm layer. On the most comlr~cte0 treatment, uptake from this layer was only 50% of the uptake on non-com- pacted treatments. In the 0-30-cm layer, the relative uptake of 4SCa generally decreased with increasing depth.

(2) Subsoil compaction caused a slight differentiation in the total uptake of ~'5Ca by maize plants. The uptake was highest on non-compacted soil, but only slightly lower on subsoils compacted to 1.70 gcm -3.

( 3 ) Subso;.! co_m__~action increase0 th~ maize green tops 7ietds and the 45Ca concentration in the dry matter but decreased dry matter content.

REFER~ NCES

Coote, D.R. and Ramsey, J.F., 1983. Quantification of the effects of over 35-years of intensive cultivation on fore soils. Can. J. Soil Sci., 63: 1-14.

Hrynczuk. B., Gediga, K. and Glabiszewski, J., 1986. Uptake dynamics of 45Ca and 32t-) from different soil profile depths by some ctdti;ated plants. Proceedings of a Symposium on Ion Equilibrium in Soils and Plan!g under Intensive Fertilization Condition~, W~octaw, 1986 Part 1, pp. 129-133 (in Polish).

Lu, N. and Edwards, J.H., 1985. Injection of chemical amendments into coaaoactcO subsoils. Commun. Soil Sci. Plant Anal., 16: i 015-1027.

Kozicz, I., 1971. Influence of the compacting etfect of the whee!s of diffe~er~tly loaded tractors on soll oh~'sical properties a~d the yield of some crops. Zc~:. Prcb!. Postepow N~ uk Roln., 112:67-89 (in Polish).

SUBSOIL COMPACTION, 4SCa UPTAKE AND YIELD IN MAIZE 335

Kwasowski, E., Karczewski, T. and Skwarek, W., 1981. Effect of the drive mechanism of agri- cultural machines on so:d compaction. Postepow Nauk Roln., 5:1 ! 9-125 (in Polish).

Smie~chalski, L., 1972o Influence of soil compaction on the yields of some cereals and root crops. Proceedings of an International Scientific Congress, Putawy, pp. 23-38 (in Polish).