CONTRIBUTION TO THE KNOWLEDGE OF PHOSPHORUS IN SOME SOILS FROM THE PROVINCE OF SARAGOSSA (SPAIN) . III. Soil phosphorus dynamics in relation to plant yield*

BENIGNA R. ELEIZALDE * *

SUMARIO

Se trata de un estudio preliminar sobre el estado del fósforo en cinco grandes grupos de suelos de la provincia de Zaragoza (España). En que se ha usado un procedimiento biológico recomendado por el Departamento de Suelos de la Facultad de Ciencias Agronómicas de Gembloux (Bélgica); que consistió en un diseño experimental de 6 repeticiones para macetas con plantas y 3 repeticiones para macetas sin plantas pare cada uno de los cinco suelos. Se les ha aplicado una solución nutritiva exenta de fósforo y con una relación A/C igual a 0,97, que permitió crecer 15 plantas de centeno forrajero por maceta hasta que completase su ciclo vegetativo. Al final del cual, las plantas de centeno forrajero se cosecharon, pesaron y se analizaron pare el fósforo. Se considera la dinámica del fósforo del suelo, en relación al rendimiento obtenido en el centeno forrajero, a través de: La contribución de las fracciones del fósforo inorgánico, encontrando en los cinco suelos que la fracción soluble en cloruro de amonio influye significativamente sobre el rendimiento de fósforo de este cultivo y en el cave de los suelos calizos, la fracción P Ca puede llegar a ser significante en el suministro de fósforo al centeno forrajero. De los tres métodos rápidos de laboratorio pare la determinación del fósforo asimilable, solamente el de Van der Paaw-Sissingh refleja significativamente el fósforo del suelo absorbido por este cultivo. La diferencias de rendimientos en materia seca y en fósforo del centeno forrajero crecido en estos cinco suelos se discuten en función de los factores intensidad, cantidad, capacidad y velocidad de desorción del fósforo.

SUMMARY

INTRODUCTION

The phosphorus absorption by plant depends on the concentration of this nutrienl; in soil solution. This concentrations is govern by the rate of P transfer from solid phase to soil solution.

This can be summarized in the following scheme proposed by FRIED and SHAPIRO (1967); confirmed by COOXE and lARSEN (1966); GUNARY and SUTTON (1967).

P in solid phase P in soil solution P in neighborhood roots-plant P in top plant

From this scheme it can deduce:

1) There is a phosphorus transfer solid phase to the soil solution, being in volved in this process, all the labil P froms, that is to say, the quantity factor. Among these forms, the surface P, and certain compounds in the inorganic P fractions can be considered, which according to their water solubility can be contributed to P in soil solution.

2) P in soil solution through a diffusion process will move to the neighborhood of roots plant. There must be suitable physical conditions such as humidity, good soil particle aggregation etc. in order to facilitate, on the other hand the diffusion of this nutrient as well as a good root development.

3) The absorption of this nutrient by the plant will depend on the requirement proper to its specie, age and physiological state.

With the passing of time and because of the knowledge's obtained, the soil fertility studies related to the evaluation of the phosphorus status have supported several changes.

At a beginning, most of the soil workers have used chemical and biological procedures, and their making use of the correlation methods between plant yield and soil phosphorus obtained by extracting solution, they have tried to evaluate the situation described in the above mentioned scheme.

This gave rise to the use of a considerable number of extracting solutions, some of a universal character (Spry-Way, Morgan, Peech), others of a selective nature for the P extraction (ammonium lactate sodium bicarbonate, ammonium fluoride). In some cases these extracting solutions resorted a significant correlation with plant yield, showing in this way a correct estimation of soil phosphorus absorbed by plant; but in other cases that correlation was not obtained.

From 1957, date in which CHANG and JACKSON have published their method for the determination of the soil P inorganic fractions and, on the other hand, FRIED and SHAPIRO (1967), WILLIAMS have defined and introduced the concepts related to soil factors that govern soil fertility concerned to a nutrient, there was two generalized tendencies about the soil fertility papers published in literature.

Some (AL-ABBAS and BARBER F1964]; BALDOVINOS [1966]; GRIGG [1965]; HANATIAUX [1966]; KHANNA [1967]; PAYNE and MANNA [1965]; PLESSIS and BURGER [1965]; SMITH [1965]), has reflected the contribution of the different inorganic P soil fractions in relation to the phosphorus absorbed by a crop; others (COOKE and LARSEN [1966]; RENNIE and MCKERCHER [1 959]; VAN DIEST [1968]; WILLIAMS [1967]; MATHINGLY [1965]) through laboratory methods have studied the influence of the soil fertility factors on the phosphorus uptake by a crop.

The purpose of this study is the characterization of five great soils groups (gypsum serosem, maral serosem, terrace soil, alluvial meadow soil and brown soils) belonging to the Zaragoza province in relation to the phosphorus supply to rye-grass grown on these soils under greenhouse conditions in which phosphorus fertilizers were not applied although a suitable supply of the others nutrients was a attained.

The behaviour of these soils will be studied concerned to:

Contributed of the inorganic P fractions related to P absorbed by rye-grass.

Through the evaluation of three quick laboratory assessment of the P available to rye-grass.

How the factors of soil fertility have intervened in the supply of this nutrient to rye-grass-grown on these soils under the experimental conditions established at green house.

MATERIALS AND METHODS

The materials used consisted of the arable layer of five great soil groups (gypsum serosem, marry serosem, terrace soil, alluvial meadow soil and brown soil) belonging to the Saragossa province and they were described elsewhere (Hanatiaux, Abadía and Eleizalde, 1976) .

The methods here included, referrend to the biological procedure recomended by the soil department of the official Faculty of Agronomic Sciences at Gembloux (Belgium) as well as those used at laboratory for the P determinations in plant and soil samples.

It consist of a cereal (rye-grass tetraploide gigantum) easily grown, was sown in 10 litre pots that contained a mixture in basis of volume formed by 80% washed sand (2 mm) and 20% of soil.

The soil department of the above mentioned Faculty recomended a nutritive solution whose anion/cation ratio was 0.97 and the concentration and composition of this solution in 50 litre volume will be:

This solutions will contain 100 cc of a microelement solution which will be as follows:

The chemical reagents used were Merck, for the cations (Ca++, Mg++ and K+) were in the forms of hydroxides and for the anions (SO₄⁼ and NO3^-) were respectively sulfuric and nitric acids in the amounts and volumes corresponding to the respective m.e concentration cited above.

The trial under greenhouse, consisted of a design of 6 replicates of pot with plant and 3 replicate of pot no plant for every so~l.

On the 9th of February 1973, 30 seeds of rye-grass tetraploide gigantum were drilled per not, two days later the seedlings emerged and a thining was carried out, leaving 15 seedlings per pot.

The period of this assessment was until the completation of the growing cycle of this crop, and during this time, a supply of 600 m.e of the above nutrient solution was applied; being distributed as follows:

The above application was based on the crop growth and the criterion supported by Hanatiaux, in one of his papers (HANATIAUX, 1 966) .

2. Plant phosphorus analysis

At the and of the assements, the plants from each pot were separately harvested, weighed, dried in an oven at t = 60°C and weighed again. This plant material was well ground and well mixed. Two subsamples of 0.3 g were digested with peroxide and sulphuric acid, such as is described by VAN SCHOUNWEMBURG (1968). The phosphorus of this extract was analyzed according to the Murphy Riby method such as is recommended by VAN SCHOUNWEMBURG (1968).

In the proceding greenhouse test, the non plant pots received the same nutrient solution aplication as the other pots. When the plants of these latter pots was collected and left to dry at laboratory temperature. Once well dried, the whole of the material was passed through a 1 mm sieve in order to remove the sand particles added. The soil was well mixed and some subsamples were taken up for laboratory analysis.

In this trial I significant differences in phosphorus plant yield were found, for that reason it Nvould be useful to verify this behavior with II assessment.

For that purpose on the 1th of may 1973 rye-grass tetraploide gigantum was sown in the some pots before used in trial I and plants from each pot were harvested on the 15th of july 1973. During the period of this II trial, the same conditions described before, were followed, in other words, all that related to the use of nutrient solution, plant harvesting weighing and phosphorus analysis as well as that concerned with the soil material from the non plants pots.

In the soil material the following determinations were carried

a) The fractionation of inorganic P according to the Chang and Jackson procedure modified by HANATIAUX (]964).

The extraction of the P available according to the procedures of OLSEN (1953), BURRIEL and HERNANDO (1950) and VAN DER PAAW - SISSINGH (1968).

RESULTS AND DISCUSSION

At once these rye-grass plant had completed their vegetative cycle, they were harvested, weighed and analyzed for phosphorus. Finding that there were differences in dry matter and phosphorus yield among these soils. That induced us to carry out a second trial on the same pots and under the same conditions used in trial I once again, differences in dry matter and P yields were found. A sequence in these yields can be established.

Alluvial meadow soil > Terrace > Brown soil > Gypsum serosem > Marly serosem.

This sequence in slightly altered in trial II and is as follows:

Terrace soil > Alluvial meadow soil > Marly serosem > Brown soil > Gypsum serosem.

These dry matter and phosphorus yields in both trial I and II, are included in Tables 1 and 2 respectively.

TABLE 1. DRY MATTER AND PHOSPHORUS YIELDS IN TRIAL I

TABLE 2. DRY MATTER AND PHOSPHORUS YIELDS IN TRIAL II

This data was analyzed through a variance study (see Tables 3 and 4) from which it can be deduced that P yields in each replication belong to the same population while those found in each soil . are different and significant, showing in this way a different pattern exhibited by these soils in P dynamics.

TABLE 3. VARIANCE ANALYSIS FROM PHOSPHORUS PLANT YIELD ( TRIAL I )

TABLE 4. VARIANCE ANALYSIS FOR PHOSPHORUS YIELD OBTAINED IN TRIAL II

.

2.04 x 2 x G.79

The inorganic P fractions considered, are those solubles in ammonium chloride, ammonium fluoride, sodium hydroxide, and sulphuric acid which contents in these soils can see on Tables 5 and 6, for the soil samples from the pots of trials I and II, as well as the initial contents in these soils before both trials.

TABLE 5. CHANGES IN THE INORGANIC P FRACTIONS IN SOIL SAMPLES AFTER TRIAL I. (Data expressed in mg P/100 g soil)

TABLE 6. CHANGES IN THE INORGANIC P FRACTIONS IN SOIL SAMPLES AFTER TRIAL II. (Data expressed in mg P/100 g soil)

In these Tables 5 and 6, it can be seen that after the I and II greenhouse trial, the five soils showed a slight increase in their inorganic P fractions in relation to those obtained in the original soil samples. In these trials, phosphorus fertilization was not used, therefore it can believe that these increases can be originated by a certain alteration of the organic fraction in these soil samples proceeding from non plants pots of the I and II trials. This organic phosphorus alteration could has ocurred during these greenhouse assessments or during the drying of the mixtures (sand+soil) at room temperature during the Zaragozanos summer. The fact of these increases detected in inorganic P fractions is similar or higher than the increase obtained in these soil samples for P extracted by 6N or 2N H., SO~ (see Tables 7 and respectively).

In order to know what the contribution of these inorganic P fractions to the P absorbed by a crop. The P values of the Tables 5 and 6 were taken into account. Thus a correlation procedure between the plant P yield and the P content in these P inorganic fractions was used.

TABLE 7 TRANSFORMATIONS IN ORGANIC PHOSPHORUS IN SOIL SAMPLES AFTER I GREENHOUSE TRIAL (values expressed in mg P/100 g soil)

TABLE 8. TRANSFORMATION IN ORGANIC PHOSPHORUS IN SOIL SAMPLES AFTER II GREENHOUSE TRIAL (data expressed in mg P/100 g soil)

TABLE 9. CORRELATION COEFFICIENTS AND REGRESSION EQUATION BETWEEN PLANT P YIELD AND THE P CONTENT IN THESE INORGANIC P FRACTIONS

In both cases, the P soluble in ammonium chloride contributes significant by (r=0.93 and 0.94) to the P absorbed by rye-grass.

While the fraction extracted by sulphuric acid did not show it self to be significant in all soils (r=0.54 and 0.70); however when the data of calcareous was only taken account, these correlation coefficients become significant (r=0.80 and 0.90), showing us that in these calcareous soils in a not very long period of time this P fraction will contribute to this phosphorus supply to plants. This is agree to that mentioned by HERNANDO and DIEZ (1974) in a paper concerned to the phosphorus in Spanish soils. These authors pointed out that the fraction soluble in ammonium chloride is the former that intervenes in the phosphorus renewal! in the soil solution however if this fraction was absent in soils, the phosphorus supply can be influenced by the others inorganic P fractions.

Normally in soil laboratories there exist quick methods which in a short period of time supply information concerning to phosphorus assimilable by plants. For this purpose, a great number of extracting solutions have been used be lieving that each of them can carry out a suitable estimation of this soil phosphorus absorbed by plant.

In this study, three procedures, VAN DER PAAW - SISSINGH, OLSEN and BURRIEB - HERNANDO have been considered; because the first in a preceding study has reflected this situation (ELE~zA~DE and VAN D~EsT, 1971); the Olsen methods is widely used for calcareous soil and the Burriel - Hernando extracting solution is followed at most soil laboratories in Spain.

The values of P obtained by these three laboratory methods can be seen on Tables 10, 11 and 12 respectively.

TABLE 10. SOIL EXTRACTED BY THE VAN DER PAAW-SISSINGH METHOD (data expressed in mg P/100 g soil)

TABLE 11. VALUES OF P OBTAINED BY THE OLSEN PROCEDURE (expressed in mg P/100 g soil)

TABLE 12. SOIL P EXTRACTED BY BURRIEL-HERNANDO PROCEDURE (values are expressed in mg P/100 g soil)

In tables 10, 11 and 12 there can be seen the data of phosphorus extracted by these three laboratory procedures, which were slightly higher soil samples from the I and II trials than in the original ones. These phosphorus contents were correlated separately with the rye-grass phosphorus yield (trial I) and the total phosphorus yield of rye-grass; that can be appreciated in Table 13.

TABLE. 13. CORRELATION COEFFICIENTS (r) REGRESSION EQUATION BETWEEN SOIL P EXTRACTED BY THESE LABORATORY TESTS AND P YIELD OF RYE-GRASS

From this Table 13 it can deduce that of the three laboratory tests, that corresponding to Van der Paaw- Sissingh carried out a suitable estimation of soil P absorbed by rye-grass grown on these five soils under the experimental conditions established at greenhouse . While the other two methods ( Olsen and BurrielHernando) supplied low and non significant correlation coefficients (r=0.65 and 0.25) at trial I; increasing their correlation values with the total phosphorus yield of rye-grass (r=0.73 and 0.60), showing in this way that both extracting solutions have preferably acted on phosphorus forms which have a slow transfer to the soil solution.

In order to verify this, the fractionation of inorganic P according the Chang - Jackson procedure in soil samples of both trial after the action of these extracting solutions, was carried out.

The influence of these extracting solutions on the phosphorus fraction solubles in ammonium chloride and sulfuric acid can be seen on the values included in the Tables 14 and 15.

The differences between the initial contents of these inorganic P fractions and those obtained after the action of these extracting solutions, will reflect which the Olsen and Burriel - Hernando have remove from these inorganic P fractions. In Table 16 it can be seen the correlation between these differences and the soil P extracted by Olsen and Burriel -Hernando methods.

T A BLE 1 4

INFLUENCE OF OLSEN EXTRACTING SOLUTION ON THE PHOSPHORUS FRACTIONS SOLUBLES IN AMMONIUM CHLORIDE AND SULPHURIC ACID (values are expressed in mg P/100 g soil)

TABLE 15. INFLUENCE OF BURRIEL - HERNANDO EXTRACTING SOLUTION ON THE PHOSPHORUS FRACTIONS SOLUBLES IN AMMONIUM CHLORIDE AND SULPHURIC ACID (values are expresed in mg P/100 g soil)

.

TABLE 16. CORRELATION COEFFICIENTS BETWEEN SOIL P EXTRACTED BY OLSEN AND BURRIEL - HERNANDO SOLUTIONS IN RELATION TO THEIR INFLUENCE ON THE P FRACTIONS SOLUBLES IN AMMONIUM CHLORIDE AND SULPHURIC ACID

From the correlation coefficients obtained, it can deduce that the Olsen extracting solution influences more than the Burriel - Hernando method on the P fraction soluble in ammonium chloride and both laboratory procedures have extracted phosphorus significativelly from the P fraction soluble in sulphuric acid.

3 ) Through t.he soil f ertility f actors

If the soil phosphorus supply to plant, depends of the concentration of this nutrient at a given time in soil solution (intensity factor), being this concentration govern by the rate of P transfer from the solid phase to soil solution (desorption rate), that is controlled by the total quantity of P labil (quantity factor) and by the capacity inherent to support this concentration.

These above mentioned soil fertility factors have been evaluated through laboratory procedures acquirables to the soil department belong~ng to the Experimental Station Aula Dei at Saragossa (Spain) .

The values of these soil fertility factors can be seen on Table 17.

According to the values of this table 17, these five soils can bc classified as follows:

Low intensity factor (Maral serosem and Brown soil) moderate intensity factor (Gypsum serosem and Terrace soil) high intensity factor (Alluvial meadow soil).

Moderate intensity factor (Gypsum, maral Serosems and Brown soil ) .

High intensity factor (Terrace soil and Alluvial meadow soils) .

In order to be able reflet it, in these five soils two different criterions were followed, one is that postured by OZANNE "et al" (1968) in which this factor is evaluated as the quantity of P adsorbed at given range of 0.25 to 0.35 ppm P in final solution. The other is that recommended by RENNIE and McKERcHER (1959) in which this factor is considered as the ~o saturation of the soils in relation to the total maximum P adsorption. In our case due to the fact that under the experimental conditions at greenhouse the no P fertilization, it was believe that the ratio Q/I will be better reflet by the surface P ~O in relation to the maximum P adsorption at site I in these soils. With any one of these two criterions used, as it can seen in Table 17, these soils have shown different values and therefore this will influence on the different behaviour which shows theso five soils.

TABLE 17. VALVES OF INTENSITY, QUANTITY, CAPACITY AND RATE OF P DESCRIPTION

The rate or P desorption was determined by the equation proposed by COOKE and LARSEN (1966) and indicates that:

Soils with slow P renewal in soil solution

(Gypsum, maral Serosem and Brown soil).

Soils with a high P renewal in soil solution

(Terrace soil and alluvial meadow soil from Gállego river).

In order to verify this classification, the criterion supported by WILLIAMS (1967) in which the intensity and quantity factors are estimated in relation to the dry matter and P plant yields was followed.

Thus in Table 18, it can be observed that of the three laboratory procedure used, that of anionic resin at 1 hour of equilibrium time, reflects well the difference among these five soils concerned to this intensity factor.

TABLE 18. CORRELATION BETWEEN THE DRY MATTER YIELD OF RYE-GRASS AND THE VALUES OF INTENSITY

In relation to the quantity factor, it has been well defined under these experimental greenhouse conditions by the total amount of P desorbed by 14 water consecutives extractions and by the anionic resin methods at 72 hours of equilibrium time due to the fact the both procedures have been significatively correlated with the phosphorus yield of rye-grass (see on Table 19).

TABLE 19. CORRELATION BETWEEN P YIELD OF RYE-GRASS AND QUANTITY FACTOR

How can it explain the differences exhibited by these soils in phosphorus yield c.t the I trial ?

Initially, it has influenced that these soils have different P concentrations in soil solution (intensity factor) and latter this differences of yield was not so marked between two soils such as terrace soil and alluvial meadow soil from Gállego river, because they have similar quantity and rate of P desorption factor. While in thc other soils this difference of yield is higher than the precedent group, because these soils have lower values in the intensity, quantity and rate of P desorption and then the simultaneous a^tion of these three soil fertility factors has regulated the phosphorus absorption by rye-grass.

In trial II there was a decrease in crop yield compared to that exhibited in trial I. These yields in trial II keing aproximately 67, 49, 34 and 33~o of the initial obtained in trial I for marry serosem, terrace soil, alluvial meadow soil and gypsum serosem respectively.

This can perhaps be explained because these soils under natural conditions they have different values in the quantity factor and the capacity factor evaluated through two different criterions supplies a similar information related to this behaviour. As a consequence, in gypsum and marry serosems this decrease of yield in trial II was more pronunced in the former due to a lower value in the capacity factor.

Brown soil showed a rye-grass yield in trial II, which was the 40% of that exhibited in trial I. This soil compared with the serosem group has lower quantity and capacity factors although a similar rate of P desorption and then for that it will become easily exhausted than the precedent group. Under a phosphorus fertilization this soil will be require also lower amount but it will be by in continuos manner.

In terrace soil and alluvial meadow soil from Gállego river, it can observe that a similar quantity factor under no fertilization conditions, these soils have supported a plant yield in trial II in a 47 and 33% of that obtained in trial I, that means that tines was a replect of their different values in the capacity factor.

CONCLUSIONS

1 ) Among the inorganic phosphorus fractions, those solubles in ammonium chloride and in sulphuric acid have intervened in the phosphorus supply to rye-grass grown on these five soils.

2) From three laboratory procedures used by the estimation P available only the of Van der Paaw-Sissing has well reflected the soil P absorbed by rye-grass.

3) Thc Burriel - Hernando and Olsen extracting solution influence more on the P forms of slow transfer at soil solution due to the fact that show a significant correlation coefficient with the P Ca fraction.

4) The intensity and quantity factors were well reflected by soil P extracting according to the anionic resin method at t=1 and 72 hours respectively, as well as the sum of 14 water consecutive extractions for the latter factor.

5) The phosphorus supply to rye-grass in trial I and II was govern by the soil fertility factors.

In trial I, the difference in plant yield was due in two soils (Terrace soil and Allovial meadow soil) to the intensity factor, while in the other soils it was by the simultaneous action of (rate of P desorption, intensity and quantity).

In trial II, the capacity factor was the responsible of the differences obtained in plant yields.

ACKNOWLEDGMENT

The author thanks to Ingo Heck belonging to soil Department of Faculty of Agronomic Sciences at Gembloux (Belgium) for the furnishing of the experimental technique to be used in the greenhouse.

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