Bulgarian Journal of Soil Science

18-31

Authors: Ognyan Kostov

It has been reviewed papers and personal investigations about soil tropical soils fertility. It was pointed out the importance of tropical soils for quantity and quality of yields of many crops. It was discussed soil quality, soil degradation, integrated nutrient management, maximization of the use the use of organic materials, balanced use of inorganic fertilizers, minimizing losses of plant nutrients, methods for conservation cropping management of low productive soils, polices for soil and fertility management and composting waste to improve and maintained tropical soils fertility.

42-52

Authors: Idris A.D., Olaniyan J.O., Affinnih K.O. and Ajala O.N

The study evaluated the forms and distributions of potassium in red laterite soils. Top soils samples 0 – 30cm, were randomly collected from thirty different major agricultural areas across Patigi LGA of Kwara State. Descriptive statistics was performed while regression analysis was used to assess the correlation between potassium forms. Results showed the exchangeable sodium (Na+ ) was very low to moderate. The values ranged from 0.00 – 0.27 cmol/kg soil. The exchangeable potassium (K+ ) of the soils is very low with values of 0.11 – 0.30 cmol/kg. Calcium (Ca2+) values ranged between 0.10 and 5.1cmol/kg soil while magnesium (Mg2+) ranged from 0.1 – 2.9 cmol/kg soil. The total potassium (K) obtained by concentrated perchloric acid (HClO4) had higher values (3.1 – 11.0 cmol/kg of soil) than other potassium types studied. The available potassium (K) was positively and significantly correlated with HCl Extractable K+ (r = 0.98); HNO3 Extractable K+ (r= 0.93) and HCl04 Extractable K+ (r=0.90) at P<0.01. The values of the extractable potassium increased in the order of NH4OAC

75-81

Authors: Nidal Shaban, Sergei Bistrichanov, Eman Kadum, Miroslav Tityanov

Sustainable development in education of horticulture imposes envolvement of new system in education of agricultural experts (in particular vegetable growers); include – etical view off point to the reality of production,synthesis of traditional practices (crop rotation, mixed crops, etc.), the love to the land inherited from ancestors and modern scientific achievements from this perspective which will have a positive environmental effect over the agrarian ecosystems and the environment in general. From this perspective lectures and practices should be based on the principles of integration of different systems and methods of production; this will include sustainable management of fertilizing and irrigation; energy use associated with production; integrated control of pests with sustainable application in the farms. These principles should be presented in a special section entitled “Sustainable Growing of Vegetables” which will form the basic knowledge related to the topic; they should be incorporated in a suitable place in the respective sections for individual crops where developed of details with active participation of trained people. In order to overcome the specified problems and ensure sustainable development of the sector its necessary to provide well-trained people who know not only the traditional technologies used at present but also the principles of sustainable agriculture as well, especially related with keeping natural resources to next generations.