The Effect of Irrigation and Fertilization on Cotton Growth and Development under Greek Conditions
Aug 3, 2018
The effect of two irrigation levels and two N-fertilization practices on the growth and productivity of two Greek cotton varieties (e.g. Zeta-2, Korina) was investigated in a field experiment carried out in central Greece, in 1997. The irrigation levels are 320 mm/yr (I2) which is normal for the study area, and an amount by 20% lower, viz. 250 mm/yr (I1). The fertilization practices include a) classical dressing with 160 kg N/ha (F1) and b) same amount of total N applied by fertigation (F2). The experimental design was split-split plot with five blocks. The development and growth features of cotton were determined in five distracting samplings throughout the growing period. Fiber percentage and quality characteristics were also determined. It was found that the lower irrigation did not affect the final seed- and lint-cotton yield. Contrarily, the lower irrigation exhibited a significant positive effect on crop earliness, especially for the cultivar Zeta-2, which performed by about 500 kg/ha and 200 kg/ha greater yield respectively of seed- and lint-cotton at the first pick. No effect of fertilization practice on the yield was found at any of the pickings. This was especially the case for “Zeta-2” which performed identical yields for the two fertilization practices. The plants receiving the higher irrigation (I2) performed a leaf area index (LAI) rather greater than the I1 plants, viz. 4 vs. 3.1 at the beginning of August. Also the plants under the common fertilization practice exhibited higher LAI at the first stages but these differences were disappeared later. The fiber length was the only cotton quality character significantly affected by the treatments. The combination of low irrigation and fertigation gave the longest fiber length. The above results give evidence that irrigation and fertilization in cotton may be reduced in accordance to the imposed low input agriculture in the future without a serious variation in the cost/benefit ratio. This can be of particular importance especially for adverse years when an early crop is highly required.