INFLUENCE OF SOIL PREPARATION AND FERTILIZATION SYSTEM BEFORE PLANTING ON THE PLUM BEHAVIOUR

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1 INFLUENCE OF SOIL PREPARATION AND FERTILIZATION SYSTEM BEFORE PLANTING ON THE PLUM BEHAVIOUR M. Iancu Research Institute for Fruit Growing Piteşti Mărăcineni, Romania Abstract Among the fruit species grown in Romania, the plum sp. is the leader both in terms of acreage and number of trees, because it claims lower soil needs. The, most of plum orchards are established on clayey-illuvial soils. An essential property of the heavy-clay soils is the clay accumulation in the upper part of B horizon which leads to a low permeability of water and air, as well as a higher resistance to deep root penetration. On the other hand, the air-water regime of this type of soil is not high by favorable for the fruit tree growing, showing frequently, an excess or deficit of moisture under our climatic conditions. To improve these conditions and to find the fruit trees response to them, some studies in this respect were carried out. This paper shows the comparative results of these studies. It was used the following experimental scheme: A Factor location of the experimental field and investigation period, with the graduations: a 1 flat land on the 3 rd terrace of Doamnei River on a typic planosol (PLti) with a clayey texture in Colibasi village, 14 Km N for from Pitesti. The soil had over the -2 cm depth, a 56.3% clay content (particle size Ø<.2 mm, (C), a 1.29 g/cm -3 bulk density (BD), a 6. mm h -1 satured hydraulic conductivity (Ks), and a 1.68% humus content; over the 2 cm depth, the above soil properties had the following values: 63,6% C, 1,35 g/cm - ³ BD, 1.3 mm h -1 Ks, and.8% humus content. Anna Spath cv. grafted on Mirobolan ( ) was used in this experiment. a 2 flat land in Smeura willage in the Pitesti Plain, 7 km far from Piteşti westwards, on an albic pseudo-gleyed, vertic luvosol (SPvs-pz), with a medium loamy clayey texture. The soil had over -2 cm depth the following values of the properties studied: 4.8% C, 1.22 g/cm -3 BD, 5.6 mm -1 Ks and 2.12% humus content; over 2 cm depth, the above soil properties had the following values: 4.1%C, 1.34 g/cm -3 BD, 3.2 mmh -1 Ks, and 1.68% humus content. With this plot, Agen 77 cv. grafted on Mirobolan ( ) was studied. B Factor soil tillage system (STS) before plantyng: b 1 ploughing at 23 cm soil depth, b 2 deep ploughing at 4 cm depth, b 3 deep ploughing at 55 cm, b 4 = deep loosened at 55 cm depth, spaced at 1 m as well as ploughing at 23 cm. C Factor soil fertilization system (SFS): c 1 1 kg/tree manure application on tree planting; c 2 fertilized with 4 t/ha manure (a 1 ) and with 6 t/ha manure (a 2 ) applied on the entire area before soil tillage. Therefore, a trifactorial experiment like 2 x 4 x 2 designed as subdivided blocks in 4 replications was organized. The average rainfalls for March 1 May 31 period in the year of tree planting was 76 mm, in a 1, representing 135% of the normal value for the above period, and 62.1 mm in a 2, representing 111% of the normal value for the above period. There were stressed the physical and chemical modifications caused by the soil preparation and fertilization in each location. Also, the effects of the experimental factors on the tree growth and fruiting as well as on the chemical compounds were quantified. In a 1 deep ploughed at 55 cm vs. 22 cm ploughed determined a 111% decrease in trunk cross sectional area (TCSA) growth, over the first six years from tree planting, while in a 2 a 143% increase in TCSA growth was found in the deep ploughing treatment versus the normal ploughing one, over the same period of time. Deep ploughing at 55 cm, versus the normal ploughing ar 22 cm determined an increase in fruit yield by 322% in a 2 ( in the 2 nd year after the trees came into bearing) and by 12% (kg/cm 2 TCSA) in a 1 soil (in the first tree fruiting years). Key-words: soil type, soil plowing, deep plowing 99

2 1. Introduction Among the fruit species grown in Romania, the plum sp. is the leader both in terms of acreage and number of trees, because it claims lower soil needs. The most orchards are established on clayey-illuvial soils. An essential property of the heavy-clay soils is the clay accumulation in the upper part of B horizon which leads to a low permeability of water and air as well as a higher resistance to deep root penetration. On the other hand, the air-water regime of this type of soils is not well fit for the fruit tree growing, showing frequently an excess or deficit of moisture under our climatic conditions. To improve these conditions and to find the fruit trees response to them, some studies in this respect were carried out. This paper shows the comparative results of these studies. 2. Material and methods The following experimental scheme was used: Factor A location of the experimental field and investigation period, with the graduations: a 1 flat land on the 3 rd terrace of Doamnei River on a typic planosol (PLti) with a clayey texture in Colibasi village, 14 Km N for from Pitesti. The soil had over the -2 cm depth, a 56.3% clay content (particle size Ø<.2 mm, C), a 1.29 g/cm -3 bulk density (BD), a 6. mm h -1 satured hydraulic conductivity (Ks), and a 1.68% humus content; the 2 cm depth, the above soil properties had the following values: 63,6%, 1,35 g/cm - ³ BD, 1.3 mm h -1 Ks, and.8% humus content. Anna Spath cv. grafted on Mirobolan ( ) was used in this experiment. a 2 flat land in Smeura willage in the Pitesti Plain, 7 km far from Pitesti westwards, on an albic pseudo-gleyed, vertic luvosol (SPvs-pz), with a medium loamy clayey textured. The soil had over -2 cm depth the following values of the properties studied: 4.8% C, 1.22 g/cm -3 BD, 5.6 mm -1 Ks and 2.12% humus content and over 2 cm depth, the above soil properties had the following values: 4.1%C, 1.34 g/cm -3 BD, 3.2 mmh -1 Ks, and 1.68% humus content. With this plot, Agen 77 cv. grafted on Mirobolan ( ) was studied. Factor B soil tillage system (STS) before ploughing: b 1 plowed at 23 cm soil depth, b 2 deep ploughing at 4 cm depth, b 3 deep ploughing at 55 cm, b 4 = deep loosened at 55 cm depth, spaced at 1 m as well as ploughing at 23 cm. Factor C soil fertilization system (SFS): c 1 1 kg/tree manure application on tree planting; c 2 fertilized with 4 t/ha manure (a 1 ) and with 6 t/ha manure (a 2 ) applied on the entire area before soil tillage. Therefore, a trifactorial experiment like 2 x 4 x 2 designed as subdivided blocks in 4 replications was realized. The average rainfalls for March 1 May 31 period in the year of tree planting was 76 mm, in a 1, representing 135% of the normal value for the above period, and 62.1 mm in a 2, representing 111% of the normal value for the above period. Results 3.1. Influence of tillage system on some soil physical properties On average, in the four soil tillage treatments in the case of the PLti (a 1 ) from Colibaşi, versus SPvs-pz from Smeura (a 2 ), the clay content was significantly higher by 154% at -2 cm depth, by 164 % at 2-4 cm depth and by 154% at 4 cm depth (fig.1). The soil deep plowing at 55 cm increased the clay content by 18% at -2 cm depth in the case of a 2 versus the normal ploughing at 22 cm. Under the same conditions, a significant difference in the case of a 1 was not noticed. Deep soil ploughing at 55 cm determined an important raise in bulk density by 17% at -2 cm in a 1 and by 19% in a 2 vs. the normal ploughing at 22 cm. However, below 3 cm depth, the deep ploughing at 55 cm determined a significant decrease in bulk density values vs. the normal one, and this was more obviously in a 1. (fig.1) On average, in the four soil tillage treatments in a 2, the macroporosity values were higher for all depths vs. a 1. The differences were significant for the first five depths. Soil deep ploughing at 55 cm in both soil types determined a significant increase in macroporosity vs. plowing at 22 cm. This was more obviously below 3 cm. A similar response but to a greater extent was found with the saturated hydraulic conductivity. (Fig.2) In the planting year, in the case of a 1, an increase in soil moisture (% from field capacity, FC) on the -1 m soil layer occurred in deep ploughing at 55 cm () treatment versus ploughing at 22 cm (). In the case of a 2 an increase in soil moisture occurred in the b 1 versus b 3, especially in the first half of the growing season (fig. 3). 1

3 Clay (%) Clay (%) Clay (%) 1,1 1,2 1,3 1,4 1,5 1,1 1,2 1,3 1,4 1,5 1,1 1,2 1,3 1,4 1, Bulk density (g/cm²) -7 Bulk density (g/cm²) -7 Bulk density (g/cm²) Fig. 1. Influence of the management system on two soil types on the clay content and bulk density; the significance of the experimental factor graduations is shown in text at chapter Material and methods 11

4 Macroporosity (%) -7 Macroporosity (%) -7 Macroporosity (%) Satured hydraulic conductivity (mm/h) -7 Satured hydraulic conductivity (mm/h) -7 Satured hydraulic conductivity (mm/h) Fig. 2. Influence of the manageament system on two soil types on macroporosity and satured hydraulic conductivity; the significance of the experimental factor graduations is shown in the text at chapter Material and methods 12

5 Moisture (% from F.C) V 1VII 7X 22V 17.VII 7.IX 1.X Fig. 3. Influence of the soil management system (, ) on the soil moisture; the significance of experimental factor graduations is shown in the text at chapter Material and metods 3.2. Influence of tillage system on the soil chemical properties On average, in the four soil tillage treatments a 2 showed a higher significant humus content by 134% at -2 cm depth, by 157% at 2-4 cm and by 211% at 4 cm versus a 1. On the contrary, in a 1, the P content was significantly higher by 163% up to 289% and K content by 173% up to 194% for all 3 depths vs. a 2. The deep soil ploughing at 4 and 55 cm for both soil types led to a lower humus and P and K contents but on the other hand, determined an increase in these components in deeper layers, especially at a 4 cm depth, versus the normal one at 22 cm (fig. 4) Influence of soil tillage and fertilization on some chemical compounds in tree leaves On average, in the four soil tillage treatments and the two fertilization treatments, a 1 showed a higher N content by 163% and of P content by 117% vs. a 2. The K content was not significantly different under the same conditions. For both soil types and two fertilization treatments the deep ploughing at 55 cm led to a significant increase in K content by 113% and a decrease in P content by 1.5 times vs. the normal ploughing at 22 cm. The N content was not significantly different in the two soil types and four soil systems. Application of 6 t manure/ha on the entire area before the land preparation increased significantly the N content by 113% versus the application of 1 kg manure in the planting hole. The P content was as much as 11% and also a significant decrease in the K content by 1.12 times was noted (table 1).This response of the fertilization treatments was more obviously in case of a 2 vs. a 1 and in soil deep ploughing vs. the normal one (table 1). 13

6 ,5 1 1,5 2 2, ,5 1 1,5 2 2, ,5 1 1,5 2 2, Humus (%) Humus (%) Humus (%) Deptha (cm) Phosphorus mg/1g Phosphorus mg/1g Phosphorus mg/1g Potassium mg/1g Potassium mg/1g Potassium mg/1g Fig. 4. Influence of the soil management system on some chemical properties of the soil; the significance of the experimental factor graduations is shown in the text at chapter Material and methods 14

7 Table 1. Influence of management and fertilization system on some chemical components of tree leaves A. Average values of the experimental factors (A, B, C) Chemical compounds LSD 5% DL 5% c1 c2 LSD 5% N NS Phosphorus Potassium NS B. Factors interaction (A/B/C) Chemical compounds c1 c2 c1 c2 c1 c2 c1 c2 N Phosphorus Potassium %LSD 1= between graduations of C factor when A,B factors are constant, 2 = between graduations of B factor when A, C factors are constant; 3= between graduations of A factor when B,C factors are constant, NS= non significant; The significance of experimental factors graduations is shown in the text at chapter Material and methods 3.4. Influence of soil preparation and fertilization on the fruit tree growth Having in view that for each soil type (and experimental place) various cultivars were used, the effects of soil preparation and fertilization on the tree response is separately presented for each soil type. In a 2 (with Agen cv. 77) for both fertilization systems, deep ploughing at 55 cm led to a significant increase in TCSA by 143%, of number of fruit per tree by 195% and of fruit yield per tree by 322%, vs. the normal one at 22 cm. Although the average fruit weight was higher by 12%, the difference was not significant. The positive effects on growth and fruit yield versus normal ploughing was also found in the other two deep plowing treatments (at 4 cm and deep loosening at 5 cm), but to a smaller extent (table 2). Table 2. Influence of management and fertilization systems on the growth ( ) and fruiting (1984) of plum Agen 77 cv. The studied character A. Average values of the experimental factors (B,C) c1 c2 TCSA (cm 2 ) No. fruit/tree NS Fruit Weight (g) NS NS Yield kg/tree

8 The studied character B. Factors interaction (BxC) c1 c2 c1 c2 c1 c2 c1 c2 1 2 TCSA(cm 2 ) No. fruit/tree Weight fruit (g) NS NS Yield kg/tree %LSD for factors interaction B/C 1= constant B factor; 2 = constant C factor. The significance of experimental factor graduations is shown in the text at chapter Material and metods ; TCSA = trunck crosssectional area of the tree, NS = non significant On average, in the four soil tillage systems the application on the entire surface of 4 t manure per ha before the land preparation, versus fertilization with 1 kg manure per tree, led to a significant increase in TCSA by 18% and of fruit yield per tree by 139%. The effects of the fertilization treatments were more obviously in the case of deep ploughing at 55 cm versus the other treatments for land preparation. (table 2) In a 1, the fertilization treatments (SFS) did not cause a significant difference in the tree growth and fruit bearing. Therefore, in the case of this soil type, only the effects of soil tillage on the tree behaviour were analyzed in a monofactorial experiment arranged as a block design with 4 replications. Fruit yield (t/ha) was the highest in b 3 and the difference versus b 2 was significant. Differences were higher when the yield efficiency (kg/cm²tcsa) was calculated. In this case the fruit yield in b 3 was higher by 113% versus b 2, 12% versus b 1 and 136% versus b 4 (table 3). Differences between treatments were mainly attributed to both fruit number/ TCSA and medium fruit weight/tcsa ratios, respectively. The higher fruit number and average fruit weight/cm² of TCSA in b 3 versus b 1 can be explained by higher soil moisture in b 3 versus b 1 during the second half of the growing season, when the flower buds formation mainly determined the fruit number per tree, and when the increase in fruit weight was intensive. Table 3. Influence of soil management systems on annual growth of trunk cross-sectional area during and fruit bearing ( ) for the Anna Späth plum-tree cultivar Treatments Fruit yield Fruit number per Fruit weight TCSA growth Kg/cm 2 t/ha cm 2 of TCSA g/cm 2 of TCSA (cm 2 ) TCSA b b b b % L.S.D The significance of experimental factor graduations is shown in the text at chapter Material and methods 16

9 Discussions The great water accumulations both in a 1 and a 2 exceeding by far their field capacity (FC) can be explained by the heavy rainfalls recorded in both soil types, a bit before and right after trees planting. So, as it was mentioned in the chapter Material and methods, the rainfalls recorded during March May in the 1 st year after tree planting exceeded the normal values (multianual average of that period) by 135% in a 1 and by 111% in a 2. The various moisture excess during the period of land preparation and meanwhile (deep plowing at 55 cm and plowing at 22 cm) can be explained by the specific properties of the two soil types. So, in the case of a 1, the temporary moisture excess was found until the 1 st of July, when the trees developed more intensely, while in a 2, the moisture excess was achieved early and in late autumn when tree growth is getting slower. Also, in a 1, the water excess was much higher in the case of deep plowing at 55 cm versus 22 cm. In a 2 it was just the contrary, the water excess exceeding the field capacity in the case of normal plowing at 22 cm than in deep plowing at 55 cm. The higher water accumulations in deep plowing versus plowing at 22 cm in a 1 versus a 2 can be mainly explained by a much higher clay content in this soil type, and secondly by the more intense modifications caused by the deep plowing. Fig. 1 shows a much lower macroporosity and hydraulic conductivity in a 1 vs a 2 which determined a slower movement and consequently a greater water accumulation in the soil profile. The different water excesses turned worse the aeration conditions which in return influenced negatively the tree growth. So, the data presented showed that in a 1 soil, a 111% decrease in TCSA growth was found in the deep ploughing treatment versus the normal ploughing one, over the first four years from tree planting, while in soil a 143% increase in TCSA growth was found in the deep ploughing treatment versus the normal ploughing over the same period of time. Regarding the fruit yield, the tree response was similar in both soil tillage systems. Deep ploughing at 55 cm, versus the normal ploughing ar 22 cm determined an increase in fruit yield by 322% in a 2 soil ( in yhe 2 nd year after the trees came into bearing) and by 12% (kg/cm 2 TCSA) in a 1 soil (in the first tree fruiting years). These data from above, proved the complexity of deep ploughingn high clay content soils. So, deep ploughing is influenced by both the inner properties of soil and the climatic conditions in the following years after soil tillage. More conclusive results on the soil and climate conditions and microrelief concerning the effects of soil deep tillage on the properties of high clay soil content periodically affected by the moisture excess were also reported for Romania s conditions and cereal crops by Canarache et al., 1971; Canarache 198; Canarache and Colibasi (1985); Colibasi et al. (1989), Nicolae (1969), and for orchards by Motoc and Tudor (1962), Iancu ( ), Iancu and Negoita (1998), Iancu et al (1986). Conclusions 1. On average, in the four land preparation systems on a typical planosol (a 1 ), a higher physical clay and P, K contents, a lower humus content as well as lower values of bulk density, macroporosity and saturated hydraulic conductivity were found versus an albic vertic luvosol (a 2 ). 2. The soil deep ploughing at 55 cm caused in the upper soil profile, an increase in bulk density and K content and a decrease in macroporosity, hydraulic conductivity, humus and P contents versus the ploughing at 22 cm. In return, at the bottom of ploughed layer (bellow 4 cm) the indicators above mentioned had reverse values than those in the upper soil profile. 3. On average, for the two soil types and four soil tillage systems, 4 t manure application on the entire area before soil tillage determined a significant increase in P and K contents, versus 1 kg/tree manure at tree planting, but this did not change too much the contents in the tree leaves. 4. An 111% decrease in TCSA growth was found in the deep ploughing treatment versus the normal ploughing one, over the first four years from tree planting, in the case of a 1. In the case of a 2 a 143% increase in TCSA growth was found in the ploughing treatment versus the normal ploughing over the same period of time. 5. Soil deep ploughing at 55 cm determined an increase in fruit yield by 322% in a 2 (in the 2 nd year after the trees came into bearing) and by 12% (kg/cm² TCSA) in a 1 (the first 3 fruiting years) versus the ploughing at 22 cm. 17

10 References Canarache A., 198, Changes of soil physical properties through deep ripping (in Romanian), Producţia Vegetala Cereale şi plante tehnice, n. 11: 14-18; Canarache A., Colibaşi I., 1985, Contribuţii la studiul relaţiilor dintre condiţiile climatice şi efectul afânării adânci (scarificării), Ştiinţa Solului n. 2 p. 4-57; Canarache A., Boeriu I., Iancu M., 1971, Soil properties as a criterion to forcast the effects of trenching on pseudogley levisive soils, Mitteilungen der Konferenz Pseudogley und gley Genese und Nutzung Hzdromorfer Böden, , Stuttgart Hochenheim; Colibaşi I., Stângă I., Dumitru Elisabeta, Canarache A., 1989, Tehnologie integrată de executare a lucrărilor de scarificare (afânare adâncă) şi subsolaj (scormonire), Producţia vegetală, Cereale şi plante tehnice, n. 5., Mai 1989; Iancu M., 21. Technique for reducing subsoil compactation of pedogenetic origin, Proceedings of 3rd Workshop INCO COPERNICUS Concerted Action "Experiences with the impact of subsoil compactation on soil nutrients, crop growth and end environment, and ways to prevent soil compactation", Buşteni, Romania, June 21; Iancu M., 1997, Influence of land preparing and fertilization before tree planting on apple growth and fruiting. Proceedings of 14th ISTRO Conference, July-August, 1997, Pulawy, Poland, Tom 2A; ; Iancu M., Negoita Mariana, Influence Of Soil Management And Fertilization On Some Properties Of A Haplic Luvisol And Tree Behavior. Proceedings of the 16 th World Congress of Soil Science, CD-Rom, Symposium 2 - Management of physical properties of tilled horizons: environmental and agricultural aspects, Scientific registration nr. 194, Montpellier, August 2-26, 1998, France. Iancu M., Neamţu I., Negoiţă M., 1986, Cercetări privind stabilirea modului de pregătire a terenului în vederea înfiinţării plantaţiilor de prun pe solurile din Platforma Cotmeana, Lucrări Ştiinţifice ICPP vol. XI: ; Moţoc M., Tudor S., 1962, Comportarea pomilor pe terenurile în pantă cu soluri foarte argiloase care prezintă exces temporar de umiditate în condiţii diferite de amenajare a terenului şi de întreţinere a solului Lucrări Ştiinţifice ICHV, vol VI : 41-51; Nicolae C., 1969, Lucrarea profundă a solului podzolic pseudogleic de la Albota, Judeţul Argeş, Ştiinţa Solului., vol. 7., n.4 p ; 18