Influence of moistening conditions and methods of basic tillage on maize productivity in the Southern Steppe of Ukraine

Abstract

In the last 10-15 years, maize has reached the first place in the world in terms of yield and gross grain yield. The rapid growth rates of this culture are due to high fodder, food and technical qualities, and an extremely high positive response to genetic changes and technological developments. On irrigated lands, combined with the influence of a sufficient amount of heat energy resources, it has the highest grain yield in comparison with all other crops. In addition, corn is able to spend the smallest amount of natural or artificial moisture to obtain an additional grain. However, in the conditions of production, questions of low grain yield arise, which requires conducting relevant research on optimizing maize cultivation technologies in the south of Ukraine.

Despite the fact that maize in Ukraine is one of the most cost-effective crops in production, the net profit from its cultivation in recent years is high. In particular, in March-April 2016 corn grain prices on world markets in the dollar equivalent began to increase, which directly affected the interest of producers in the expansion of sown areas. Scientific research and practical experience of irrigated agriculture indicate that the main element of the planning and use of artificial humidification is the determination of the necessary water requirement for the formation of high and qualitative yield for specific conditions, that is, the total water consumption. Importance for the operational management of irrigation regimes is to determine the daily expenditure of moisture (daily average evaporation), which must be reconciled with the fact that this powerful factor in the impact on plant productivity can and should be regulated in accordance with other natural and technological factors.

The purpose of the study was to determine the effect of moisture conditions and methods of basic tillage on the production of corn grown in southern Ukraine. The objective of the study was to determine the influence of the investigated factors on grain yield, the proportion of the influence of factors on plant productivity, the establishment of the specific gravity of the effects of moisture and basic tillage on the formation of yields, and also the detection of the tightness of correlation-regression relations.

Field experiments were carried out during 2012-2015 according to the research methodology at the Institute of Irrigation Farming of the NAAS of Ukraine. The corn was sown after winter wheat; three irrigation regimes were laid on the background of three variants of methods and depth of tillage: The Kakhovsky hybrid was planted with a planting density of 80,000 per hectare. Watering was provided by a drainage unit DDA-100 MA. Further agrotechnique was generally recognized for Ukraine.

In field experiments, it was determined that the level of purity of corn plants was significantly dependent on the characteristics of weather conditions. So, in the dry year 2012, the analysis of yield data shows that despite the increase in irrigation rate to 3500 m³/ha, the deficit of natural moisture has led to a decrease in plant productivity. The analysis of yield data of 2013 shows that the average yield at support of soil moisture at the level of 70% of LMC (lowest moisture context) during the growing season yielded a maximum grain yield of 13.4 t/ha. Irrigation under the scheme 60-70-60% of LMC (soil protection irrigation regime) reduced the yield by 1.3-0.7 t/ha relative to optimal irrigation. In 2014, corn yields due to different factors for the creation of appropriate soil watering conditions that were determined in the scheme for irrigation ensured the yield of grain in the range of 12.1-13.4 t/ha, and its maximum level (14.5 t/ha) was obtained with maintenance of humidity in the active layer of soil at the level of 70% of LMC. Reducing pre-watering moisture in the 1st and 3rd periods up to 60% of LMC in 2015 resulted in a reduction in yields of 1.3 t/ha with water saving of 400 m³/ha or 11.4%.

It has been established that on the average in 2012-2015, the maximum grain yield of corn on the factor of tillage was obtained in deep plowing by 28-30 cm at a level of 13.15 t/ha.

Replacement by chisel loosening at a depth of 20-22 cm led to yield losses at the level of 0.45 t/ha, or in the percentage ratio of 3.4%. The application of surface tillage of 12-14 cm led to further reduction of yield by 2.67 t/ha or 20.2%.

The variance analysis of yield data, on average in 2012-2015, showed that the factor C in soil tillage has the greatest effect on the yield of 45%. The effect of irrigation regimes was within the range of 39%. The interaction of the AB factors influences crop capacity at the level of 12%, with the residual interaction being within 4%.

Correlation and regression analysis of the influence of the investigated factors on yield formation showed that the influence of the system of basic cultivation of soil is reflected by the coefficient in the formula at the level of 0.04477, which indicates a significant effect on yield. Irrigation regimes have coefficients of 0.0225 and 13.4 that reflect the residual effects on yield, which is clearly reflected in the mathematical equation of yield of the studied culture. The determination coefficient shows the degree of dependence of the variation of the dependent variable on the variation of the independent variables, that is, indicates how much observation is confirmed by the model. In the generated equation, the determination coefficient is at a high level of R² = 0.775, that is, the influence of factors has a significant effect on the yields of corn.