© 2017
Lotysh I. I., postgraduate student
(scientific supervisor – Doctor of Agricultural Sciences M. Ya. Shevnikov)
Poltava State Agrarian Academy
THE FORMATION OF THE LEAF SURFACE OF SOY SEEDING DEPENDING ON THE VARIETY, METHOD OF SOWING AND SEEDING RATE IN LOW MOISTURE OF FOREST-STEPPE
Reviewer – Doctor of Agricultural Sciences, Professor P. V. Pysarenko
            Getting the maximum possible productivity of any sort of soybeans depends on the component technologies that provide optimal formation of leaf surface and duration of photosynthetic activity. The study of photosynthetic potential of crop soybean sorts showed that the highest rate was in the areas with a seeding rate of 800 thousand/ha: row planting sowing – 2,19–2,34 million m2 days/ha for sowing in wide row – 2,16–2,27 million m2 day/ha. The intensity of photosynthesis depending on the options ranged experiment: the row planting method in the range of 11,55 to 12,40 mg CO2 dm2/day wide row planting way – from 11,33 to 12,06 mg CO2 dm2/h. Depending on the seeding rate and method of sowing was layered index according to the sorts: Romantyka – from 3,89 to 4,13 m2 leaf/m2, Ustya – from 3,88 to 3,99, Vorskla – from 3,80 to 3,92 leaf m2/m2.
Keywords: soybean, sowing, planting methods, seeding rate, photosynthesis.
Statement of the problem. Due to the intensification of soybean production there is a question of clarifying growing technology elements that have to provide high productivity. Among them crucial are periods, method of sowing and soybean seeding rate.
The proper placement of soybean plants in the area should meet the basic requirement – the best light of the leaf surface. In favorable conditions, the length of daylight soybeans require intense lighting, in the lack of which soybean does not bloom. As light-culture, it generates a high yield of only optimal for a particular grade feeding area and density of plant lighting, providing moisture and nutrients, which in turn determines the leaf amount intensity of photosynthesis, formation of beans, the amount of beans and seeds determines the value and seed quality [1, 2, 3].
The analysis of the basic research and publications in which there is a solution of the problem. The accumulation of dry substance in crops during the growing season represents the degree of productivity. During the loading of grain formation the important value is the transformation products of photosynthesis and the rate of accumulation of dry matter. At this time the subsystems of producing and preserving are closely connected and the grain yield is formed as a result of its interaction with the photosynthetic apparatus. The orientation process of drysubstance accumulation and redistribution between producing and maintaining systems is one of the assessments of performance. Therefore, more accurate information on the features and productivity process can be obtained by determining the accumulation of drysubstance of the plants during the growing season [4, 5, 7].
The highest and the best quality products can be received in crops with optimal size of leaf area, the best course of its formation and structure [2, 6]. The optimal growth of leaf surface and the formation of a high photosynthetic capacity of leaves largely depend on the validity of production technologies that ensure a longer working of leaves’ apparatus.
It is believed that foundation by which photosynthetic activity as a result generated soybean crop is formation of optimum leaf surface area. The leaf surface absorbs the solar energy and synthesizes the organic compounds that are used for the formation of new plants and crops. According to studies conducted in the Steppes of Ukraine we know that the optimal leaf surface area for soybeans should be 40-50 thousand m2/ha. If the area of leaf surfaceis less, the optical-crop biological structure is not optimized and therefore PAR is not used efficiently. However, and greater leaf surface area is undesirable, as a result of significant shade the leaves fall off in the lower tier and the rest is not effective [1, 3]. The researchers found that the rate in soybeans can vary quite widely, depending on the genotype of the variety, environmental conditions and farming practices in the region for its growing [4].
The purpose and methodology of the research. The aim of the research was to establish the optimal density of planting soybeans by proper selection of seeding rate and  the planting method that would ensure optimal plant growth and the development and the productivity of plants. Determing the time of sowing take to the attention that early period corresponds to the minimum soil temperatures (8-10 °C), where possible germination of soybean seeds. The optimum planting period was determined by the soil warming up to +12-14 degrees respectively. Late sowing period corresponded to the temperature of the soil to 16-18 degrees respectively. In the first two cases must also take into account moisture providing of toplayer of soil. Late sowing period often accompanied increase soil temperature to 16-18 degrees respectively. In the first two cases must also take into account water supply of sufficient top soil. Late sowing period often accompanied by low humidity seed layer of soil. The meteorological conditions during the experiments were varied and fully characterized the features of the climate of the area.
The results of research. In the research, we studied the effect of terms, the methods of planting and seeding at enhancing the photosynthesis process, including the formation of leaf surface area (table 3.13). First of all, it should mentioned the sort specificftion in the manifestation of the signs of leaf surface. We've found that soybean varieties are not very different in terms of space leaves more significant influence exercised seeding rates and methods of sowing. By row planting way and seeding rate of 500 thousand/hectare area of ​​leaf surface was 40,1-41,5 thousand m2/ha. Increased seeding rate of 600 thousand/ha helped to raise this figure to 41,3-43,5 thousand m2/ha, 700 thousand/ha – 43,7-46,3 thousand m2/ha, 800 thousand/ha – 44,3-44,8 thousand m2/ha. By wide-planting way and seeding rate of 500 thousand/hectare area of ​​leaf surface was 30,5-40,9 thousand m2/ha.
Тable 3.13
The surface of soybean leaves area (thous. m2/ha) depending on the sort, the method of planting and seeding rate (average for 2013–2015)
Seeding
thousand/ha	Sort	
	Romantyka	Ustya	Vorskla	
Rowing method of sowing, 15 cm	
500	40,1	41,5	40,8	
600	41,3	43,5	42,7	
700	43,7	46,3	45,4	
800	44,8	44,8	44,3	
Wide-sowing method, 45 cm	
500	39,5	40,9	39,9	
600	40,5	42,8	42,1	
700	43,2	45,7	44,8	
800	44,5	44,5	43,7	
Increased seeding rate of 600 thousand/ha helped to raise this figure to 40,5-42,8 thousand m2/ha, 700 thousand/ha – 43,2-45,7 thousand m2/ha, 800 thousand/ha – 43,7-44,5 thousand m2/ha. Rowing method of sowing increased leaf surface area compared to the wide-sowing method. Among the sorts of plants slight increase in leaf area observed by sowing sort Ustya.
For photosynthesis and connected with it the process of biological nitrogen fixation the important factor is the penetration of light into soybean leaves all tiers. Only optimal density in sowing plants formed a habit that promotes good lighting, uniform formation of its leaves, beans and seeds, high intensity of photosynthesis and seed yield. To take into consideration the process of photosynthesis as a basis for the creation of biological agents should consider such factors as the formation of photosynthetic potential, determining the net productivity of photosynthesis, setting the intensity of photosynthesis and leaves index.
The indicator of photosynthetic potential describes the potential of photosynthetic apparatus of plant soybean sorts and that is the sum of the daily performance leaves sowing area for the entire growing season or in part. In our study photosynthetic potential for row planting method Romantyka sort of seeding rate of 500 thousand/hectare was 2,29 million m2 d/ha. Increasing the seeding rate of 600 to 800 thousand/ha contributed to its increase to 2,32-2,34 million m2 d/ha. In sort Ustya increasing in seeding rate amounted to 2,22; 2,23; 2,24; 2240000 m2 d/ha, grade Vorskla – 2,17–2,19 mln m2 d/ha, respectively (table 3.14). The positive dynamics in increasing of photosynthetic potential was observed by wide-way rows planting of 45 cm. In areas with a seeding rate of 500 thousand/ha sort Romantyka raterop photosynthetic potential was 2,23 million m2 d/ha, sort Ustya – 2,18, sort Vorskla – 2,130,000 m2 d/ha.
Table  3.14
The formation of photosynthetic potential (AF million m2 days/ha) and the net photosynthetic productivity (NPP g/m2 per day), depending on the sort, the method of planting and seeding rate (average for 2013–2015)
Seeding
thousand/ha	Sort	
	Romantyka	Ustya	Vorskla	
	PP	NPP	PP	NPP	PP	NPP	
Rowing method of sowing, 15 cm	
500	2,29	10,13	2,22	9,80	2,17	9,60	
600	2,32	10,23	2,23	9,86	2,18	9,62	
700	2,32	10,24	2,24	9,87	2,18	9,64	
800	2,34	10,31	2,24	9,89	2,19	9,66	
Wide-sowing method, 45 cm	
500	2,23	9,82	2,18	9,60	2,13	9,44	
600	2,25	9,93	2,19	9,66	2,14	9,47	
700	2,25	9,94	2,19	9,67	2,15	9,50	
800	2,27	10,03	2,20	9,71	2,16	9,54	
The increasing of seeding rate to 600 thousand/ha increased this figure to 2,25; 2,19 and 2,14 million m2 days/ha respectively to sorts. For seeding rate of 700 thousand/ha crop photosynthetic potential was respectively 2,25; 2,19 and 2,15 million m2 days/ha seed rate per 800 thousand/hectare – 2,27; 2,20 and 2,16 million m2 d/ha.
Thus, the study of the photosynthetic potential of crops of soybean sorts showed that the highest rate was in areas with a seeding rate of 800 thousand/ha: rowing method of sowing – 2,19-2,34 million m2 days/ha for wide-sowing method 2,16-2,27 million m2 d/ha. Besides the photosynthetic potential an important indicator of photosynthesis in crops is a net productivity of photosynthesis. The net photosynthesis efficiency is the ratio of weight of dry substance growth of plants over time to one leaf surface. The value of this indicator in our study options depending on the experiment ranged between 9,44 g/m2 per day (sort Vorskla, wide-mode sowing, seeding rate of 500 thousand/ha) to 10,31 g/m2 per day (sort Romantyka, row method of sowing, seeding rate of 800 thousand/ha).
In our studies, the net productivity of photosynthesis by way of row planting sorts of Romantyka seeding rate of 500 thousand/hectare was 10,13 g/m2 per day. Increasing the seeding rate of 600 to 800 thousand/ha contributed to its increase 10,23-10,31 g/m2 per day. In sort Ustya for a corresponding increase in seeding rate amounted to 9,80; 9,86; 9,87; 9,89 g/m2 per day, sort Vorskla – 9,60–9,66 g/m2 per day, respectively. Positive dynamics was also increase in net photosynthesis productivity for wide-way method of  planting of 45 cm. In areas with a seeding rate of 500 thousand/ha grade Romantyka rate of net photosynthesis crop productivity was 9,82 g/m2 per day, sort Ustya – 9,60, grade Vorskla – 9,44 g/m2 per day. Increasing the seeding rate to 600 thousand/ha increased this figure to 9,93; 9,66 and 9,47 g/m2 per day, respectively to sorts. For seeding rate of 700 thousand/ha net productivity of photosynthesis crop amounted to 9,94; 9,67 and 9,50 g/m2 per day for seeding rate of 800 thousand/ha – 10,03; 9,71 and 9,54 g/m2 per day.
To explain the performance of photosynthetic potential and performance of net photosynthesis rate measured photosynthesis and the leaves index. The intensity of photosynthesis, or the rate of carbon dioxide absorption is a piece of day light time per unit of the surface (CO2 dm2 mg/h). The value of this indicator in our study options depending on the experiment varied: for row planting method in the range of 11,55 dm2 mg CO2/year (sort Vorskla, seeding rate of 500 thousand/ha) to 12,40 mg CO2 dm2/h (sort Romantyka, seeding rate of 800 thousand/ha) by way of wide-sowing – 11,33 mg of CO2 dm2/hr (sort Vorskla, seeding rate of 500 thousand/ha) to 12,06 mg CO2 dm2/hr (sort Romantyka, seeding rate of 800 thousand/ha) (table 3.15).
Тable 3.15
The intensity of photosynthesis (IP, CO2 dm2 mg/h) and a leaf index (LI m2 leaf/m2), depending on the sort, 
the method of planting and seeding rate (average for 2013–2015)
Seeding
thousand/ha	Sort	
	Romantyka	Ustya	Vorskla	
	IP	LI	IP	LI	IP	LI	
Rowing method of sowing, 15 cm	
500	12,18	4,05	11,79	3,93	11,55	3,88	
600	12,31	4,08	11,87	3,95	11,57	3,88	
700	12,32	4,11	11,88	3,97	11,59	3,90	
800	12,40	4,13	11,90	3,99	11,63	3,92	
Wide-sowing method, 45 cm	
500	11,81	3,89	11,55	3,88	11,33	3,80	
600	11,95	3,94	11,62	3,90	11,39	3,83	
700	11,96	3,97	11,63	3,93	11,44	3,85	
800	12,06	4,00	11,68	3,92	11,47	3,87	
The research has found that the rate of photosynthesis by way of row planting sorts of Romantyka seeding rate of 500 thousand/hectare was 12,18 mg CO2 dm2/h. Increasing the seeding rate of 600 to 800 thousand/ha contributed to its increase 12,31-12,40 mg CO2 dm2/h. In sort Ustya for a corresponding increase in the intensity of photosynthesis seeding rate was 11,79; 11,87; 11,88; 11,90 mg CO2 dm2/h in a variety Vorskla – 11,55; 11,57; 11,59; 11,63 mg CO2 dm2/h respectively. By way of sowing wide-grade Romantyka, the figure of 500 thousand seeding rate/ha was 11,81 mg CO2 dm2/h. With the increasing seeding rate from 600 to 800 thousand/ha made 11,95-12,06 mg CO2 dm2/h, sort Ustya – respectively 11,55 mg CO2 dm2/h and 11,62-11,68 mg CO2 dm2/h, sort Vorskla – 11,33 mg CO2 dm2/h and 11,39-11,47 mg CO2 dm2/h.
Leaves index, or layered security soybeans, we determined by the ratio of the total leaf area of ​​plants (leaf m2) to 1 m2 of sown area. Our research showed that the layered index of soybean sorts was most important in the phase of ripening green beans. Further, as a result of partial mutual shading of plants and yellowing of lower leaves, this value decreased. Depending on the seeding rate and method of sowing was layered index according to varieties: Romantyka – from 3,89 to 4,13 m2 leaf/m2, Ustya – from 3,88 to 3,99, Vorskla – from 3,80 to 3,92 leaf m2/m2.
Depending on the variety Calibration Romantyka layer index for row planting method increased from 4,05 m2 leaf/m2 Calibration for 500 thousand/ha to 12,40 m2 leaf/m2 Calibration for 800 thousand/hectare. To sort these figures have Ustya value of 3,93 and 3,99 m2 leaf/m2 for class Vorskla – 3,88 and 3,92 m2 leaf/m2 respectively. By way of wide-seeding layer index was lower and amounted to a variety of Romantyka seeding rate of 500 thousand/ha leaf 3,89 m2/m2, with a seeding rate of 600 thousand/hectare – 3,94 m2 leaf/m2, with a seeding rate of 700 thousand/ha – 3,97 m2 leaf/m2, with a seeding rate of 800 thousand/hectare – 4,00 m2 leaf/m2. To sort mouths of these indicators were appropriate value – 3,88; 3,90; 3,93 and 3,92 m2 leaf/m2 for class Vorskla – 3,80; 3,83; 3,85 and 3,87 m2 leaf/m2.
Soybeans are very sensitive to light intensity and photoperiodism. Getting the maximum possible for a given grade soybean productivity directly depends on the component technologies that provide optimal formation of leaf surface and duration of photosynthetic activity.Thus, study of photosynthetic potential of soybean sorts showed that the highest rate was in areas with a seeding rate of 800 thousand/ha: horizontal for sowing – 2,19-2,34 million m2 days/ha for wide sowing – 2,16-2270000 m2 d/ha. The intensity of photosynthesis by way of row planting varieties of Romantyka seeding rate of 500 thousand/hectare was 12,18 mg CO2 dm2/h. Increasing the seeding rate of 600 to 800 thousand/ha contributed to its increase 12,31-12,40 mg CO2 dm2/h. The intensity of photosynthesis depending on the options ranged experiment: the row planting method in the range of 11,55 mg CO2 dm2/h to 12,40 mg CO2 dm2/h, wide sowing method – 11,33 mg of CO2 dm2/h to 12,06 dm2 mg CO2/year. Depending on the seeding rate and method of sowing was layered index according to varieties: Romantyka – from 3,89 to 4,13 m2 leaf/m2, Ustya – from 3,88 to 3,99, Vorskla – from 3,80 to 3,92 leaf m2/m2.
Conclusions:
         1. Soybean is sensitive to changes in size and shape in the area of ​​power plant crops. For optimal density and area of ​​the principal amount of plant nutritionbeans formed on the main shoot in liquefied – on lateral branches. The negative effect of excessive thickening leads to lodging, premature yellowing and falling leaves. Changing the seeding rate of 500 to 800 thousand/ha similar seeds for sowing conventional horizontal mounting helped to increase the height of the lower beans from 13,9 to 15,7 cm for wide-seeding the aisle 45 cm – from 14,3 to 14,4 cm.
2. An important condition for obtaining high yields of soybean seeds are optimal stand density of plants appropriate means for sowing and the size of leaves apparatus in particular. Getting the maximum possible for a given sort of soybean productivity directly depends on the component technologies that provide optimal formation of leaf surface and duration of photosynthetic activity.
3.The study of photosynthetic potential of soybean sorts showed that the highest rate was in areas with a seeding rate of 800 thousand/ha: horizontal for sowing – 2,19-2,34 million m2 days/ha, for wide sowing – 2,16-2,27 million m2 d/ha.
4. The intensity of photosynthesis depending on the options ranged experiment: the row planting method in the range of 11,55 mg CO2 dm2/h to 12,40 mg CO2 dm2 /h, wide sowing – 11,33 mg of CO2 dm2/h to 12,06 mg of CO2 dm2/h. Depending on the seeding rate and method of sowing was layered index according to varieties: Romantyka – from 3,89 to 4,13 m2 leaf/m2, Ustya – from 3,88 to 3,99, Vorskla – from 3,80 to 3,92 leaf m2/m2.
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