The possibilities of the elimination of continuous cropping negative implications on the grain yield and microbial soil diversity were investigated. A stationary field experiment was established on Luvi-Haplic Chernozem. Statistically higher grain yield was found in the variant with mineral fertilization and straw and organic fertiliser Veget® incorporation (5.58 t.ha−1) compared with the variant with mineral fertilization only (4.87 t.ha−1) and with the variant with mineral fertilization and straw incorporation (4.90 t.ha−1). Statistically higher straw yield was found in the variant with mineral fertilization and straw and organic fertiliser Veget® incorporation (6.21 t.ha−1) compared with the variant with mineral fertilization only (4.41 t.ha−1). By cultivar Ebi, the grain yield was significantly higher in comparison to the cultivar Petrana. The lowest metabolic diversity of microbial communities and their respiration activity was found out in the variant with mineral fertilizer. On the other hand, the increase of functional diversity of microorganisms, their respiration activity and the number of cultivable bacteria was found in the variant with mineral fertilization and straw incorporation as well as in the variant with mineral fertilization and straw and organic fertiliser Veget® incorporation.
Authors:Éva Lehoczky, Z. Tóth, A. Kismányoky and T. Kismányoky
The effect of four NPK fertilizer rates (NPK[1:1:1]: 0, 300, 600,
900 kg active ingredients·ha
) was studied on the growth of maize
and on weed infestation - bio-mass production and nutrient uptake of weeds - in
four replications in a 35-year old long-term maize continuous cropping field
experiment (Keszthely, Hungary). The weed flora was recorded on 1 June, 2003 in
the 6-8-leaf development stage of maize. The effect of the increasing rates of
fertilizers was analyzed and evaluated from the results of biomass production
as well as the nutrient uptake of weeds and maize, respectively. On the
experimental plots 9 weed species were
registered at the date of sampling, from which 4 species were perennial and 5
species were annual ones. All the weeds were collected from 1 m² areas of each plot and the different weed species were
separated from each other. The fresh and dry weights of the canopy of maize and
the different weed species were measured. The
nutrient (NPK) contents of maize and weed samples were measured in the
laboratory. Total and species scale nutrient concentration, as well as per-unit
nutrient uptake of maize and weeds were compared. The increasing rates of
mineral fertilizers had a significant effect on the biomass production and on
the nutrient uptake of weeds. Significant differences were also found between
the biomass production and nutrient uptake of the different weed species.
Authors:S. A. Colecchia, P. De Vita and M. Rinaldi
A 2-year conservation agriculture experiment was conducted in Southern Italy on durum wheat continuous cropping. Aim of the research was to assess the durum wheat productivity and grain quality in reduced soil tillage systems, according to conservation agriculture principles. The interactions among experimental treatments and climate revealed a close relationship among grain yield, grain quality and wheat growth conditions. Specifically, conventional tillage (CT, plowing and 2 disc harrowing) showed in the 2-year period higher grain production than reduced tillage treatments, minimum (MT, 1 disc harrowing) and No tillage (NT), especially for good crop water availability (3.29 t ha–1 of grain yield in CT, 2.67 in MT and 2.54 in NT). The amount of rainfall (above the average in both years) and its distribution in the growing seasons (more regular in the first year) strongly influenced wheat-grain quality indices (11.97% of protein content in the first year and 9.82% in the second one). Also, the wheat quality resulted more sensitive to the “Year × Tillage” interaction, with differences among tillages more evident in the second year and favourable to NT and MT. Spectral vegetation indexes (NDVI and TVI) measurements at flowering, have been shown to be useful to support farmers in N-late application for improving grain wheat quality. From this experiment carried out during the conversion period and in wet years, wheat managed with CT resulted in higher grain yield and quality, while only test weight showed a significant “Year × Tillage” interaction. Further indications emerged on the need to supply additional (10–20%) seed amount at sowing and crop nitrogen fertilizer in the first transition years in reduced tillage systems compared to conventional ones.
The effect of various fertiliser treatments on the yield of maize hybrids was studied on the basis of 26 years of data obtained in a long-term bifactorial split-plot experiment set up in 1967. The seven treatments (NPK ratio 2:1:1) applied were as follows (rates per hectare): 1. Control (no fertiliser), 2. 100 kg NPK, 3. 200 kg NPK, 4. 300 kg NPK, 5. 400 kg NPK, 6. 600 kg NPK, 7. 800 kg NPK. The maize was grown with the conventional cultivation techniques in continuous cropping. The results of analyses carried out with three different methods (analysis of variance, cumulative yield analysis and regression analysis) all indicated that under the given conditions the yield of maize hybrids was highest at an NPK fertiliser rate of 200-400 kg ha
. The effect of fertilisation on the maize yield was significant in 21 of the 26 years. Combined analysis of variance for the years showed that the year effect (quantity of rainfall) had the greatest effect on the maize yield, but although the year effect had a fundamental effect on the yield level it did not influence the fertiliser response pattern. The fertiliser responses of the maize hybrids were described by fitting four types of functions (quadratic, square root, inverse exponential, linear-plateau) to the yield data. It was found that when selecting the best function a consideration of the regression deviations (measured yield - calculated yield) was just as important as the coefficient of determination (R
). In 12 of the 26 years the fitting of the quadratic function was not significant and overestimated the fertilisation optimum. The fertiliser response curve generally has a broad maximum which is far better described by the square root function than by the quadratic. If the fertiliser response pattern includes a depressive phase, a square root function should definitely be used in place of the quadratic function. If the maximum of the response surface forms a plateau (as opposed to a maximum point) a linear-plateau function or an inverse exponential function can be recommended. In the present work the linear-plateau function gave the best results.