EFFECT OF COMMON BEAN (PHASEOLUS VULGARIS L.) HARVEST DATE AND METHOD ON THE ORGANIC NUTRIENTS ACCUMULATION RATE

Anna Wondołowska-Grabowska¹, Andrzej Kotecki^2
1 Department of Plant Cultivation, University of Agriculture in Wrocław, Poland
² Department of Plant Cultivation, Wrocław University of Environmental and Life Sciences, Poland

ABSTRACT

Over 1996-1998 field and laboratory experiments were carried out to define the effect of genetic factor, bean harvest dates and methods on the rate of organic nutrients accumulation in the seeds, pods and stems. The following were researched: a) bean cultivars represented by three forms: small-seeded - `Mela´, medium-seeded - `Słowianka´ and small-seeded - `Jubilatka´, b) harvest dates (every 7 days), from the 7^th day following the end of flowering to full plant ripeness, c) harvest methods (threshing): direct (A) - hand-made threshing of seeds directly after cutting, two-stage (B) - hand-made seed threshing once the whole cut plants desiccated, two-stage (C) - hand-made threshing following the seed desiccation in pods previously separated from the plants directly after their cutting. As plants were ripening, the content of water in seeds was decreasing, and the process of wilting was faster than in pods and stems. Two-stage harvest B, as compared with direct harvest A, showed a more favourable effect on the accumulation of dry matter in seeds. The interaction of factors (cultivar x date) decreased, along with ripening, the content of total protein and crude fat in bean seeds, and an increase in the energy value and the share of nitrogen-free extract. The share of respective plant parts (seeds, pods and stems) in the accumulation of nutrients was changing with the ontogenetic development. The share of seeds increased, while the share of stems in the accumulation of total protein and nitrogen-free extract decreased. While comparing the three harvest methods for cultivars, direct harvest A showed most favourable for the content of crude ash, and the two-stage harvest B - for the energy value in all the cultivars researched.

Key words: common bean, harvest dates and methods, organic nutrients, organic nutrients accumulation.

INTRODUCTION

Legumes, especially coarse-grained, are the second, right after cereals, important source of protein and it is possible to obtain from them, under optimum climate and soil conditions, a two-fold higher protein yield as they are richer in protein than the cereals grain [7,22]. A considerable position of legumes is also due to the fact that the seeds of these plants cannot be substituted by vegetables, and bean seeds, as far as their nutritive value is concerned, are only inferior to broad bean and pea seeds [3]. The chemical composition of seeds of the plant species compared shows that the percentage of carbohydrates and fat in bean is higher than in the seeds of pea and faba bean, and a low percentage of protein [6,7].

The climatic factor slightly affects the changes in the accumulation of carbohydrates in seeds. There are recorded considerably greater fluctuations and changes, quantitative and qualitative, of both proteins and fat. Low temperature causes the accumulation of a greater amount of fat, water deficit - proteins. High temperature decreases the content of protein, and especially of seeds from direct threshing.

The intensity of total nitrogen accumulation in bean decreases after plant flowering, and the seeds stored in pods contain more different forms of nitrogen than the seeds directly-threshed, which means a prolonged seed development, especially of the youngest ones, in pods [8].

The harvest method and the rate of seed desiccation result in differences in the organic nutrients accumulation intensity. All that is confirmed by research into, e.g. faba bean, pea, yellow and white lupin as well as soybean [8,10-12,16-18,24]. The two-stage harvest is considered more favourable compared with the direct harvest due to the effect of prolonged ripening and mild final seed desiccation in pods after plant cutting. All that has triggered research into bean, especially into cultivars of a varied seed-size.

The aim of the present research was to determine the effect of the harvest date and method as well as the share of bean plant parts on the dynamics of organic nutrients accumulation in seeds while ripening.

MATERIAL AND METHODS

Field and laboratory experiments, 3-factor in `split-plot´ design, in four replications, were carried out over 1996-1998, at Krzeszów in the Sudety Mountains, 450-500 m above sea level. The following were researched: a) bean cultivars (Table 1) represented by three forms: small-seeded - `Mela´, medium-seeded - `Słowianka´ and coarse-seeded - `Jubilatka´, b) harvest date (every 7 days), from the 7^th day after flowering, to full plant ripeness, c) harvest methods (threshing): direct (A) - hand-made seed threshing directly after cutting, two-stage (B) - hand-made seed threshing after cut plants desiccation, two-stage (C) - hand-made threshing after seed desiccation in pods. Regardless of the harvest method, directly prior to threshing for 10 plants from each plot the following were determined: the number of pods per plant, the number of seeds per pod and per plant, fresh and dry matter of seeds, of pods and of stems, seed weight per pod (based on the quotient of the sum of seed weights per plant and the number of pods per plant).

The experiment was set up every year on brown soil, formed from loamy sands, located on medium loam IV b class, of mountain cereal-potato complex. Soil pH was slightly acidic (1996, 1998) and acidic in 1997. The soil richness in phosphorus, potassium and magnesium in the first two years was high, while in the third year - very high.

Potato constituted a forecrop for bean. In autumn pre-winter plough was carried out, and the spring pre-sowing soil preparation was limited to indispensable cultivating (cultivator + cage roller). Directly prior to sowing rototiller was used. Bean was fertilized with nitrogen before sowing at the amount of 30 kg.ha^-1 in a form of 28% nitro-chalk. As a result of the application of full dose of manure under the forecrop and because of a high richness of soil, phosphorus and potassium fertilization was not applied. The seeds were treated with Funaben T (thiuram) seed dressing. Throughout the research years sowing involved certified PB `Mela´ seeds and `Jubilatka´ and `Słowianka´ B seeds. Pocket sowing, two seeds each, was carried out by hand with the 30 cm row spacing, every 5 cm in a row, down to about 4 cm deep. After emergence a single plant was removed from the pocket, obtaining the plant density of 67 plants per 1 m². During the vegetation period weed control treatments were conducted a few times. Over all the research years, to prevent from diseases, Miedzian 50 WP (50% of Cu) was applied (3 treatments every 7 days) as well as a negative selection.

Analyses of the chemical composition of the plant material obtained (seeds, pods and stems) were carried out following standard methods; total nitrogen - with a modified Kjeldahl´s method and converted into total protein using the 6.25 coefficient, crude fat (ether extract) - with the Soxhlett-Hendel method of the residue following fat extraction in the Soxhlet´s apparatus, crude fibre - with the Henneberg-Stohmann method, crude ash - by plant material burning in electric oven at 600°C. Nitrogen-free extract was calculated deducting the total content of basic nutrients from 100. Based on the chemical analysis, the energy value of 1 kg of dry matter was calculated in MJ by multiplying the 5.92 coefficient by oat units.

Due to a varied number of days over years, from the end of flowering to full ripeness, for the purpose of three-year synthesis, there were selected harvest dates of similar physiological ripeness of seeds. The synthesis involved, based on seed moisture, six stages of ripeness: early green, green, green-and-yellow, yellow, early full and full. The content of water in stems, pods and seeds was defined with the oven-drying method at 105 ± 2°C over 5 hours.

The temperature and rainfall distribution for Krzeszów is given in Figs 1 and 2.

RESULTS

The length of respective bean development stages depended on the moisture-temperature factors and was a result of their cultivar properties (Tables 2 and 3). The period from sowing to emergence of bean was mainly affected by temperature and was longest in 1997 and lasted almost three weeks. The earliest plant emergence, already after 11-12 days, was recorded in 1996. In all the research years `Słowianka´, as compared with `Jubilatka´ and `Mela´, flowered 1 to 3 days later, in 1996 and in 1997 - flowering 6 to 8 days longer, and in 1996 - the longest vegetation period which lasted 140 days. The flowering of `Jubilatka´, as compared with the other cultivars, was shortest in all the experimental years and its vegetation period was longest in 1996. In the moist year of 1996, in the process of seed formation, in `Jubilatka´ the early green stage was longer, while in `Mela´ and `Słowianka´ - the green stage. In the other research years there was observed a time convergence of seed ripeness stages for the cultivars researched, as for `Jubilatka´ - only in 1997 the process of seed formation and maturing was longer.

The content of water in seeds due to the interaction of cultivars and harvest dates, defined directly after plant cutting, decreased along with ripening, and the desiccation process was faster than in pods and stems (Fig. 3). The lowest three-year water content mean was recorded in `Mela´ plant parts.

Two-stage harvest (B), as compared with the direct harvest (A), for the interaction of cultivars and harvest methods, was more favourable for the accumulation of dry matter in seeds, especially over their formation until yellow ripeness and usually the process lasted until full ripeness (Figs 4, 5, 6).

The analysis of the effect of the harvest date in respective cultivars on the structure of dry matter of overground parts, irrespective of the harvest methods, showed a steady increase in the share of seeds, accompanied by a decrease in the share of stems and leaves, starting from early green ripeness until full ripeness (Figs 7 and 8). While comparing the three harvest methods for respective cultivars, the share of seeds in the accumulation of dry matter was higher in two-stage harvest plants (B) and significantly higher in `Mela´.

The interaction of factors (cultivar x date) was decreasing, along with ripening, the content of total protein and crude fat in bean seeds, accompanied by an increase in the energy value and the share of nitrogen-free extract (Table 3). In `Jubilatka´ and `Słowianka´ the content of these nutrients got stabilized over yellow ripeness (total protein, crude fat) and full ripeness (NFE), while in `Mela´ the content of total protein - over yellow ripeness, and crude fat and NFE - in full ripeness. Direct harvest A showed most favourable for the content of crude ash, while two-stage harvest (B) - for the energy value in all the cultivars researched. `Jubilatka´ seeds, as compared with those of `Mela´ and `Słowianka´, recorded a higher content of crude fat, NFE and the energy value. The highest content of crude ash, of all the cultivars studied, was observed in `Mela´, while that of total protein - `Słowianka´ (Fig. 9).

The content of total protein in pods decreased gradually until full ripeness in the three cultivars (Table 4). Pods obtained from direct harvest A, in `Jubilatka´ and `Słowianka´, accumulated more NFE as compared with two-stage harvest (B) and (C), while in `Mela´ the highest accumulation of this nutrient was recorded for two-stage harvest C. Two-stage harvest B showed most favourable for the content of crude ash in the three cultivars compared.

The highest content of total protein, fat and crude ash was recorded in `Jubilatka´. `Mela´ recorded the highest content of NFE and the highest energy value (Fig. 10).

The chemical composition of stems was determined by the genetic factor, harvest date and weather, and less considerably by the harvest method (Table 5). From early green ripeness to full ripeness the content of total protein, fat and crude ash, NFE and the energy value decreased, however the content of crude fibre increased. Stabilizing of most of the nutrients mentioned coincided with yellow ripeness and early full ripeness (fat, ash - yellow ripeness; NFE, energy value - early full ripeness). The stems of `Jubilatka´, as compared with those of `Mela´ and `Słowianka´, contained more total protein, fat and crude ash, NFE, and less crude fibre (Fig. 11).

The share of respective plant parts (seeds, pods and stems) in the accumulation of nutrients changed over the ontogenetic development (Figs. 12-16). The share of seeds in the accumulation of total protein and NFE increased, while that of stems decreased. As for the accumulation of ash and crude fibre, there was observed a dominant share of stems. However the process of ripening did not affect considerably the share of pods in the accumulation of total protein and NFE.

DISCUSSION

Genetic properties of cultivars and climatic conditions determine the differences in the length of the vegetation period and morphological features of the plants [1,9,20]. Reports by Wang et al [21], Acost et al. [1] and the present research showed that the length of respective development stages in bean was, first of all, cultivar-specific and depended on the weather. With an earlier sowing, the period from sowing to plant flowering was longer, as compared with later sowing, accompanied by a shortening of the generative development, while excessive rainfall resulted in an excessive growth of vegetative organs in bean and a prolonged ripening period. According to Grzesiuk and Kulka [7], ontogenesis is accompanied by numerous transformations affecting an increase or decrease in the content of specific compounds. Their accumulation in developing seeds varies. Dry matter accumulates in seeds throughout the period of formation and reaches the highest value over full ripeness. Protein accumulates since the beginning of growth and development of seeds. At the beginning of seed formation, there accumulate albumins, and then globulins, however along with the development the quality of protein deteriorates.

Water is important for the intensity of the processes and metabolic transformations. On the first days after fertilization, the content of water in developing seeds increases slightly, after which it decreases sometimes more and sometimes less regularly until full ripeness. The accumulation of storage compounds in seeds limits the space which has been occupied by water [6,7]. For that reason the content of water in pea and faba bean seeds, defined straight after cutting, decreased with ripening [10,11]. All that corresponds with the results of bean research, however the process of desiccation was faster there than in pods and stems. The seed dry-matter growth dynamics in legumes depends mostly on moisture conditions and temperature over the vegetation period [18] and the harvest method [10,11]. In years of low total rainfall, direct harvest was more favourable for the yield of soybean seeds and their structure, while in the years of high rainfall - two-stage harvest [16]. In the present research into bean, it was the two-stage harvest which was more favourable for, e.g. the accumulation of dry matter of seeds, irrespective of the rainfall.

According to the results reported by the Centre for Cultivar Testing [2,4], out of all the cultivars compared, `Mela´ seeds show a relatively low content of protein, determined by the genetic factor [20]. The highest content of protein at the beginning of the vegetation period in lupin is accumulated in leaves and stems, and then in pods. When the seed moisture decreases below 60%, an intensive protein synthesis ends [17]. In pea since the formation and ripening of generative parts, the share of seeds in the accumulation of protein is increasing, and at the end - highest, while the share of pods - lowest [5]. The content of total protein in bean seeds decreases with ripening [15]. It is confirmed by the present research into bean, as well as those reported by Kotecki and Jasińska [11], Kotecki and Kozak [12] on faba bean and by Kotecki and Kozak [13] on pea. The content of the total protein in legumes seeds is also affected by the harvest method [24]. The two-stage harvest was most favourable for the content of total protein in soybean seeds and slightly in faba bean seeds [12].The present research did not show significant differences in the content of total protein in bean seeds depending on the harvest methods.

The richness of soil in K and P enhances the accumulation of fats [7], and the genetic factor results in differences [24]. Similarly as for fibre, the harvest method did not result in significant differences in the content of crude fat in pea, faba bean and soybean [12,23,24]. The content of crude fibre in pea seeds was decreasing with ripening [13], and increasing in soybean seeds [24]. Bean seeds recorded a decrease in its content with ripening.

With faba bean seed ripening, the content of crude fibre decreased as a result of a decreasing share of seed cover of seeds getting bigger [12,19]. Ziółek et al. researching pea [23] and faba bean, Kotecki and Kozak [12] showed that the harvest method did not result in significant differences in the content of fibre, although the direct harvest was more favourable for its accumulation. The present research showed no significant effect of the harvest method on the accumulation of crude fibre in bean seeds in the cultivars compared.

The harvest method did not show significant differences in the content of crude ash in pea and soybean seeds [23,24]. Its significant effect was recorded in yellow lupin [18] and bean seeds. The content of ash increased considerably along with pod growth [14]. In the present research into bean it was shown that the content of crude ash, just like in faba bean [12], decreased with ripening.

The share of NFE and the energy value of bean seeds, just like in faba bean and pea [12,13], increased with ripening. In the present research a positive effect on the energy value was recorded for the two-stage harvest method (B).

In the present research, with ripening, the percentage share of bean seeds in the accumulation of all the nutrients analyzed increased, and of stems - decreased. The weight of all the nutrients in seeds was increasing until full ripeness and its accumulation was lower for the direct harvest, however as for stems and pods - it was just the opposite. Similar results were recorded by Kotecki and Kozak [12,13] researching faba bean and pea.

CONCLUSIONS

1. Along with plant ripening and water loss, which was faster in bean seeds and pods than in stems, the following changes occurred:

• the share of seeds in the structure of dry matter increased until full ripeness,

• the content of total protein and crude fat in seeds decreased until full ripeness, and the share of NFE increased,

• the process of a decreasing content of total protein in pods and fat in stems, crude ash and NFE in stems, accompanied by an increasing content of crude fibre in stems lasted until full ripeness.

2. Over the ontogenetic development the share of seeds increased, and the share of stems in the accumulation of total protein and NFE decreased. Stems accounted for a dominant participation in the accumulation of ash and crude fibre. The process of ripening did not change considerably the share of pods in the accumulation of total protein and NFE.

3. Course-seeded bean cultivar showed a higher content of crude fat, NFE and the energy value, while medium-seeded bean - the highest content of crude ash. The highest content of total protein was accumulated by bean of medium-size seeds.

REFERENCES

1. Acosta G., Vargas V., White J., 1996. Effect of sowing date on the growth and seed yield of common bean (Phaseolus vulgaris L.) in highland environments. Field-Crops-Research 49 (1), 1-10.

2. COBORU, 1992. Syntezy wyników doświadczeń odmianowych [Cross-cultivar experiments results synthesis]. Słupia Wielka, Warzywa strączkowe 984, 5-27 [in Polish].

3. COBORU, 1995a. Analiza postępu w hodowli roślin uprawnych w Polsce w latach 1991-1994 [Analysis of progress in crop breeding in Poland over 1991-1994]. Słupia Wielka, Warzywa strączkowe 60, 58-60 [in Polish].

4. COBORU, 1995b. Syntezy wyników doświadczeń odmianowych [Cross-cultivar experiments results synthesis]. Słupia Wielka, Warzywa strączkowe 1077, 7-33 [in Polish].

5. Cousin R., Messager A., Vingere A., 1985. Breeding for yield in combining peas. The pea crop. Eds. P.D. Habblewhite, T. Dawkins and M.C. Heath. Butterworth, London, 115-129.

6. Grzesiuk S., 1967. Fizjologia nasion [Seed physiology]. PWRiL Warszawa [in Polish].

7. Grzesiuk S., Kulka K., 1981. Fizjologia i biochemia nasion [Seed physiology and biochemistry]. PWRiL Warszawa [in Polish].

8. Grzesiuk S., Sójka E., 1961. Studia nad fizjologią dojrzewających nasion bobiku (Vicia faba ssp. minor) [Studies into the physiology of faba bean seeds ripening (Vicia faba ssp. minor)]. Rocz. Nauk Roln. 83A (4), 735-764 [in Polish].

9. Hiltmann E., Zimmermann H., 1984. The suitability of available dwarf bean cultivars for sequential cultivation. Gartenbau. 31 (5), 136-137.

10. Jasińska Z., Kotecki A., 1997. Wpływ terminu zbioru i sposobu omłotu na dynamikę zmian w dojrzewających roślinach dwu morfotypach grochu. Cz. I. Rozwój roślin i gromadzenie suchej masy [Effect of the harvest date and threshing method on the dynamics of changes in ripening plants of two pea morphotypes. Part I. Plant development and accumulation of dry matter]. Zesz. Nauk. AR we Wrocławiu, Rolnictwo 308, 173-189 [in Polish].

11. Kotecki A., Jasińska Z., 1997. Wpływ terminu zbioru i sposób omłotu na dynamikę zmian w dojrzewających roślinach dwu morfotypów bobiku. Cz. I. Rozwój roślin i gromadzenie suchej masy [Effect of harvest date and threshing method on the dynamics of changes in ripening plants of two faba bean morphotypes. Part I. Plant development and accumulation of dry matter]. Zesz. Nauk. AR we Wrocławiu, Rolnictwo 308, 125-141 [in Polish].

12. Kotecki A., Kozak M., 1997a. Wpływ terminu zbioru i sposób omłotu na dynamikę zmian w dojrzewających roślinach dwu morfotypów bobiku. Cz. I. Rozwój roślin i gromadzenie suchej masy [Effect of the harvest date and threshing method on the dynamics of changes in ripening plants of two faba bean morphotypes. Part II. Chemical composition of plants]. Zesz. Nauk. AR we Wrocławiu, Rolnictwo 308, 143-158 [in Polish].

13. Kotecki A., Kozak M., 1997b. Wpływ terminów zbioru i sposobu omłotu na dynamikę zmian w dojrzewających roślinach dwu morfotypów grochu. Cz. II. Skład chemiczny roślin [Effect of the harvest date and threshing method on the dynamics of changes in ripening plants of two faba bean morphotypes. Part II. Chemical composition of plants]. Zesz. Nauk. AR we Wrocławiu, Rolnictwo 308, 191-206 [in Polish].

14. Martinez C., Ros G., Periago M.J., Ortuno J., Lopez G., Rincon F., 1998. In vitro protein digestibility and mineral availability of green beans (Phaseolus vulgaris L.) as influenced by variety and pod size. J. Sci. Food Agric. 77 (3), 414-420.

15. Nemeskeri E., Gyori Z., Benedek A., Borin M., Sattin M., 1994. Effect of Hungarian growing conditions on seed quality of shelling beans. Proc. of the 3^rd Congress of the European Society for Agronomy, Padova University, Abano-Padova, Italy, 612-613.

16. Pisulewska E., Kulig B., Ziółek W., 1997. Zmienność i współzależności elementów struktury plonu nasion dwóch krajowych odmian soi w zależności od terminu i sposobu zbioru oraz lat badań [Variability and interactions of seed yield structure components for two domestic soybean cultivars depending on the harvest date and method and research years]. Zesz. Nauk. AR we Wrocławiu, Rolnictwo 308, 59-70 [in Polish].

17. Prusiński J., 1992. Niektóre aspekty dojrzewania nasion roślin strączkowych [Some aspects of legumes seed ripening]. Hod. Ros. Nas. 1, 26-30 [in Polish].

18. Prusiński J., 1997. Dynamika dojrzewania nasion tradycyjnej i samokończącej odmiany łubinu żółtego. Cz. I. Produkcyjność roślin i gromadzenie suchej masy w nasionach w zależności od terminu i sposobu zbioru [Dynamics of seed ripening for traditional and self-completing yellow lupin cultivars. Part I. Productivity of plants and accumulation of dry matter in seeds depending on the harvest date and method]. Zesz. Nauk. AR we Wrocławiu, Rolnictwo 308, 11-23 [in Polish].

19. Songin H., Sławiński K., Śnieg L., 1997. Wpływ sposobu i terminu zbioru na niektóre cechy biometryczne roślin, wartość siewną i skład chemiczny bobiku. Cz. II. Wartość siewna i skład chemiczny nasion [Effect of the harvest method and date on some plant biometrics, seeding value and chemical composition of faba bean. Part II. Seeding value and chemical composition of seeds]. Zesz. Nauk. AR we Wrocławiu, Rolnictwo 308, 115-122 [in Polish].

20. Szyrmer J., Dembińska J., Wawer A., 1992. Przebieg wegetacji i zmienność cech użytkowych odmian i form Phaseolus vulgaris L. [Course of vegetation period and variability of the functional characters of cultivars and forms Phaseolus vulgaris L.]. Biul. IHAR 180, 229-239 [in Polish].

21. Wang B., Chen L., Dong W., Chen Z., Chen,. Wang B., Dong W., Chen Z., 1997. Influence of sowing date on seed yield and quality in dwarf bean (Phaseolus vulgaris var. humilis Alef.). Acta Agric. Zhejiangensis. 9 (6), 285-289.

22. Załęska W., Załęski W., 1982. Plonowanie i wartość pokarmowa roślin strączkowych zbieranych na zieloną masę i nasiona [Yielding and nutritive value of legumes harvested for green matter and seeds]. Rocz. Nauk Roln. 105A (2), 121-129 [in Polish].

23. Ziółek W., Kulig B., Pisulewska E., 1997a. Dynamika zmian parametrów jakościowych nasion grochu siewnego w zależności od sposobu i terminu zbioru [Dynamics of changes of qualitative pea seed parameters depending on the harvest method and date]. Zesz. Nauk. AR we Wrocławiu, Rolnictwo 308, 49-57 [in Polish].

24. Ziółek W., Pisulewska E., Kulig B., 1997b. Kształtowanie się wskaźników zdolności kiełkowania, wigoru oraz składu chemicznego soi w zależności od sposobu i terminu zbioru [Indices of germination capacity, vigour and chemical composition of soybean depending on the harvest method and date]. Zesz. Nauk. AR we Wrocławiu, Rolnictwo 308, 73-81 [in Polish].