Preface ixdry year. Fractionating the soil by particle size and forms of P could be
simplified into a conceptual model for a better understanding of the balance of
P in soil.
Chapter 3 – In the past Century, wheat cropping has not undergone
significant changes compared with row crops while the higher input of the
agricultural chemistry insufficiently contributed to the yield increase. Along
with this, high yielding varieties of winter wheat were continually grown.
Therefore, there is a need to consider the relationship between soil quality,
environmental effects and winter wheat yield stability. To access the wheat-
based cropping effects, data was used from a long-term experiment (LTE)
“Crop Rotation” located at the Rimski Šančevi experimental field of the
Institute of Field and Vegetable Crops in Novi Sad (N 45° 19, E 19° 50). The
original experimental plots were set up in 1946/47, and modified in 1969/70. It
consists of a different crop rotations and monoculture of winter wheat
including different fertilization options. Long-term mouldboard tillage has
influenced physical soil properties and particularly altered soil structure. As a
consequence of sufficient fertilization, the considerable content of available
P 2 O 5 (24-63 mg 100g soil-^1 ) and K 2 O (33-39 mg 100g soil-^1 ) were present in
the topsoil. In contrary, unfertilized plots were not sufficiently supplied with
the available P but maintained available K content. Soil organic carbon (SOC)
decreased because of soil inversion tillage to 65% of the original content
observed at the begging of the experiment. Likewise, SOC equilibrium at the
unfertilized plots was established after 25 years of the experiment running.
Winter wheat monoculture was higher in the content of total N and soil
organic carbon (>16 g kg-^1 ), which could be explained with preservation of
physical soil properties and available water. By analyzing the long-term yields,
it was found that there is certain stability in yields at some level and relatively
small annual variation. In a time span of the experiment management yield of
winter wheat decreases at the 3-year rotation while wheat monoculture
increase yield over time. Hence, most stabile wheat yield was observed at the
3 - year rotation suggesting important role of the preceding crops and legumes
(soybean) in rotation. This study could contribute to gain awareness of winter
wheat role in a cropping systems of the temperate climate and to understand
the relationship between wheat based cropping and soil properties.
Chapter 4 – The Niger Delta region is very core to understanding gender-
based climate change issues in cassava production. This is because, the region
is a major producer of cassava and both male and female are largely involved
in the production processes. Among others, food crop production is mostly
affected by vagaries in climatic factors. This study was conducted to analyse