ECOLOGICAL POTENTIAL OF GRAIN PEGULUM CROPS IN MODERN INTENSIVE CROP ROTATIONS
Authors: Tkachuk Oleksander , Ovcharuk Vitalii 
Published: December 2020

The article discusses the ecological significance of leguminous crops grown in modern intensive crop rotation. In particular, the area under crops of common leguminous crops in Ukraine and the level of their productivity have been analyzed. A comparison is made with the acreage of the most widespread grain crops. The emphasis of the article is aimed at establishing the level of nitrogen fixation of leguminous crops, which have the largest sown areas in Ukraine. The volume of accumulation by these leguminous crops of by-products in the form of their straw and stubble is also calculated. A comparison is made according to these indicators with the most widespread grain crops grown in Ukraine. The data on the content of the main nutrients in the by-products of leguminous crops - nitrogen, phosphorus, potassium are given. On the basis of these indicators, a calculation was made of the accumulation of the main nutrients in the soil, which can come with the by-products of leguminous crops with an average yield of their seeds. We also compared the obtained indicators with the input of nitrogen, phosphorus and potassium into the soil with by-products of the most common grain crops. Based on this, a conclusion was made about the most effective leguminous crops, the cultivation of which in the modern intensive crop rotation contributes most to the stabilization of the agro-ecological state of the soil.
According to the State Statistics Service in Ukraine in 2019, the largest sown area among leguminous crops belonged to peas - 347.0 thousand hectares, which is 61.3% in the structure of all leguminous crops. In total, the sown area for leguminous crops in Ukraine is 566.0 thousand hectares, which is about 2% of the total sown area and this is a very low indicator.
Considering the average yield in Ukraine, beans can return more by-products to the soil - 3.5 t/ha, soybeans and peas - by 8.6% less, beans - by 37.1%, and least of all - chickpeas and lentils - 1.7 - 1.8 t/ha. The content of the main macronutrients in the by-products of all leguminous crops is similar and is: nitrogen - 10.0-12.0 kg/t, phosphorus - 3.4-3.6 kg/t, potassium - 4.6-5.0 kg/t.
It has been proven that an increase in the area of leguminous crops in an intensive crop rotation will have a positive effect on the agro-ecological state of the soil. In particular, growing beans allows you to get the highest mass of by-products that can be ploughed into the soil - 3.5 t/ha. Also, by-products of beans are characterized by a high content of mineral phosphorus - 3.6 kg/t, which ensures the supply of all mineral phosphorus to the soil - 12.6 kg/ha of all leguminous crops, as well as potassium - 16.5 kg/ha.
Soybean by-products are characterized by a high nitrogen content - 12.0 kg/t, phosphorus - 3.6 kg/t and potassium - 5.0 kg/t. This allows, after growing soybeans, to accumulate in the soil with by-products more mineral nitrogen - 38.4 kg/ha. Also, soybeans are characterized by a high symbiotic nitrogen-fixing ability among all leguminous crops - 120 kg/ha.
By-products of leguminous crops have a high content of nitrogen - 2.3-2.7 times, phosphorus - 1.5-1.6 times compared to by-products of grain crops. Also, when plowing soybean by-products into the soil, there will be 2 times more mineral nitrogen and 1.1-1.3 times more phosphorus than when plowing winter wheat by-products.
Key words: egumes, by-products, nitrogen fixation, nutrients, accumulation, soil.