Growth and nutrient uptake of two varieties of groundnuts under irrigation in Isra�l

Abstract

Some data on growth, development, and mineral nutrition of two varieties of groundnuts — ‘Improved Virginia Bunch’ and ‘Spanish-33’ — under irrigation are reported. There was almost no difference in the yield of pods of the two varieties, but the yield of hay was much lower in Spanish. Spanish had also a lower total yield of dry matter, a smaller leaf area, and fewer branches than Virginia. In both varieties a negative correlation was found between Net-Assimilation-Rate and Leaf-Area-Index. Under the conditions of our observations, the highest rate of dry matter accumulation per plant was at a Leaf-Area-Index of approximately 3. There was a gradual decrease in the nitrogen content of the vegetative parts from the beginning of the season until harvest time. Most of the final amount of nitrogen was taken up before the end of August. After that, there was a transportation of this element to the newly formed pods. Pods and kernels of the Spanish variety had a higher nitrogen content than Virginia. The total amount of nitrogen taken up by the plants was equal in both varieties, 22 g per sq.m. A slight decrease in the phosphorus content of the vegetative parts was found throughout the season. The percentages of phosphorus were roughly equal, but the final amounts taken up by the two varieties were different: 3.16 g P per sq.m in Virginia, 2.34 in Spanish. The plants continued to take up phosphorus until harvest time. As the season progressed, the percentages of potassium decreased in the vegetative parts as well as in the pods and pegs. The stems had the highest potassium contents. Almost all the final amount of potassium was taken up by August. Total amounts of potassium taken up by the plants were found to be 5.7 g per sq.m. in Virginia, 3.4 in Spanish. The authors wish to acknowledge the assistance of Miss HelenaBodek in carrying out the chemical analyses. This work was aided by a grant by the Israel Groundnut Production and Marketing Board.