TOTAL AND HOT-WATER EXTRACTABLE CARBON RELATIONSHIP IN CHERNOZEM SOIL UNDER DIFFERENT CROPPING SYSTEMS AND LAND USE

A study was conducted to determine the hot water extractable organic carbon (HWOC) in 9 arable and 3 non arable soil samples on Haplic Chernozem. The hot water extractable carbon represents assimilative component of the total organic matter (OM) that could contain readily available nutrients for plant growth. The obtained fraction of organic carbon (C) makes up only a small percentage of the soil OM and directly reflects the changes in the rhizosphere. This labile fraction of the organic matter was separated by hot water extraction at 80°C. In our study the HWOC content in different samples ranged from 125 mg g-1 to 226 mg g-1. On the plots that are under native vegetation, higher values were determined (316 mg g-1 to 388 mg g-1). Whereas samples from arable soils were lower in HWOC. It was found that this extraction method can be successfully used to explain the dynamics of the soil OM. Soil samples with lower content of the total OM had lower HWOC content, indicating that the preservation of the OM depends on the renewal of its labile fractions

Uticaj lokaliteta gajenja, mikrobioloških đubriva i oplemenjivača zemljišta na produktivnost heljde (Fagopyrum esculentum Moench)

This study was aimed at investigating the productivity of buckwheat taking into account growing regions, especially altitude, since this species does not have demanding soil requirements. The experiments were conducted during 2009 and 2010 in two localities: Valjevo (the village of Jasenica at 300 m altitude - 2009 and the village of Jovanja at 160 m altitude - 2010), and Nova Varos (the village of Radijevići at 1,065 m altitude). Soil of the experimental plots at both localities was characterized by acidic chemical reactions, with 3-5% of humus. In addition, the soil was rich in potassium, but poor in phosphorus. Within the objective test, with four replications, microbiological fertilizers Bactofil and Slavol were applied just before planting, alone or in combination with soil additives (hydrogel and zeolite). Half of each plot was fertilized foliarly, by the application of microbiological fertilizer Slavol using the concentrations of 50 ml per 10 liters of water. As compared with the control (no fertilizer application), in all variants of fertilization with a top dressing, increased grain yields were obtained. Significantly higher grain yields of buckwheat were obtained in the first locality, especially in the variant of fertilization with the combined use of Slavol and soil conditioner hydrogel.U ovom radu ispitivana je produktivnost heljde u zavisnosti od lokaliteta gajenja, prvenstveno nadmorske visine, kao i od primene mikrobioloških đubriva i oplemenjivača zemljišta. Ogledi su izvedeni tokom 2009. i 2010. godine na dva lokaliteta: u ravničarskom lokalitetu Valjeva (u 2009. godini, selo Jasenica koje se nalazi na 300 m nadmorske visine i u 2010. godini, selo Jovanja na 160 m nadmorske visine) i brdsko-planinskom lokalitetu Nova Varoš (selo Radijevići, na 1.065 m nadmorske visine). Zemljište na oglednim parcelama u oba lokaliteta je bilo kisele hemijske reakcije, sa 3-5% humusa, slabo obezbeđeno pristupačnim fosforom i dobro obezbeđeno kalijumom. U okviru cilja ispitivanja, u četiri ponavljanja, na ispitivanim lokalitetima primenjena su mikrobiološka đubriva Baktofil i Slavol neposredno pred setvu, samostalno ili u kombinaciji sa oplemenjivačima zemljišta (hidrogel i zeolit). Polovina svake elementarne parcele bila je prihranjena folijarno, mikrobiološkim đubrivom, Slavolom u koncentraciji od 50 ml na 10 l vode. U odnosu na kontrolnu varijantu (bez primene đubriva), u svim varijantama đubrenja sa prihranjivanjem su dobijeni veći prinosi zrna. Značajno veći prinosi zrna heljde su dobijeni na prvom lokalitetu, posebno u varijanti kombinovane primene Slavola i oplemenjivača zemljišta hidrogel

Uticaj plodoreda i đubrenja na sadržaj lakopristupačnog kalijuma

The objective of this study was to investigate effects of rotation and fertilization on readily available potassium in soil at long term experiment 'Plodoredi' at Rimski Šančevi, Novi Sad. The study treatments were: fertilized and unfertilized three-year crop rotation (wheat-maize-soybean), fertilized and unfertilized two-year crop rotation (wheat-maize). The unfertilized plots were established 1946/1947, while the fertilized one was set up in 1969/1970. Since 1986, on fertilized plots mineral fertilizers with phosphorus, potassium and manure were not applied because of a high P and K content. Nitrogen is used every year on fertilized plots at 120 kg ha-1 for maize and 100 kg ha-1 for wheat. The result suggests that long term application of fertilizers have major effect on potassium content in both years and soil layers. Differences among two-and tree-year rotation in available potassium content were statistically significant only in the 30-60 cm layer. Low content of potassium could contribute to lower yield formation, particularly in dry years, however our study showed that chernozem has high potential for potassium release from clay mineral. On the other hand as a result of the long-term fertilization considerable accumulation of potassium occurred at fertilized plots.U radu su dati rezultati istraživanja uticaja plodoreda i đubrenja na sadržaj lakopristupačnog kalijum u zemljištu. Eksperimentalni rad je izveden na oglednim poljima Instituta za ratarstvo i povrtarstvo na višegodišnjem ogledu 'Plodoredi'. Višegodišnja primena đubriva imala je značajan uticaj na sadržaj lakopristupačnog kalijuma, dok razlike između dvopoljnih i tropoljnih rotacija nisu utvrđene. Sadržaj lakopristupačnog kalijuma na neđubrenim rotacijama se nalazi u nivou optimalne obezbeđenosti nakon 55 godina od njihovog zasnivanja, dok je njegov nivo na đubrenim parcelama značajno viši od optimalnog i nije potrebno njegovo unošenje đubrivima

The possibility of maize gluten application for weed control in maize and soybean

The objective of this study was to determine the effects of maize gluten on the weeds number and dry biomass in the maize and soybean experiment. Pre-emergence maize gluten application resulted with an effective weed control in maize, whereas the soybean had the significant loss of plants, due to the gluten fitotoxicity. Post-emergence application was found to be less successful compared with pre-emergence application particularly for soybean. Panicum cruss-galli L. was the most frequent weed in the both experiment. Maize gluten rate of 300 g m2 could be recommended in control of the broad leaf weeds in maize cropping as an alternative herbicide thus a substitute for mineral nitrogen. Our research can contribute to the improvement of the weed control in sustainable cropping systems

Soil fertility and phosphorus fractions in a calcareous chernozem after a long-term field experiment

In the present study, the long-term effects of crop rotation and fertiliser (manure, harvest residues and mineral fertilisers) use on the presence of phosphorus and its fractions at different soil depths was monitored and analysed in relation to the long-term use of particular maize growing systems. The 270 analysed soil samples were obtained as a part of a long-term two-factorial trial with four replications initiated in 1965. The plan of divided plots (split-plot design with randomised variants) was adopted and the following factors were analysed: (1) Fertilising systems: single-crop system (control, NPK, NPK + maize remains, NPK + manure) and two-crop rotation-maize / barley (NPK + manure) and (2) Soil layers at different depths: 0-20 cm, 20-40 cm, and 40-60 cm. The highest value of readily available phosphorus was found in all studied soil layers in the two-crop rotation treatment with organic and mineral fertilisers. On the other hand, the treatments involving manure application resulted in the highest content of total and organic phosphorus, whereby a 27-70% increase was observed, depending of the variant. The greatest presence of Ca-P fraction was obtained in treatments based on organic matter use, ranging from 364.4 to 482.8 mg kg(-1). Nonetheless, in the treatments involving application of organic matter, fraction related to this group had a significantly lower contribution to the total inorganic phosphorus, ranging from 56% to 86%, depending on the variant. Correlations obtained via principal component analysis (PCA) showed clear demarcation among treatments and control samples based on the use of manure and mineral fertilisers

Changes in soil carbon stock under the wheat-based cropping systems at Vojvodina province of Serbia

The aim of this study was to assess the changes in soil organic carbon (SOC) stock in relation to the carbon (C) input from nine wheat-based cropping systems and untilled grass. The SOC pool ranged from 32.1 to 49.4 Mg ha(-1) at 0-20 cm and from 94 to 171 Mg ha(-1) at 0-100 cm for the arable soil, while in untilled grassland, it was higher (54 and 185 Mg C ha(-1), respectively). SOC stock was observed to be lower at the unfertilized 2-year rotation and higher at the 4-year rotation with manure and mineral fertilization. The study showed a winter wheat yield decrease of 176.8 kg ha(-1) for a 1- Mg ha(-1) SOC stock change in the 0-20-cm soil depth. The estimated C input for SOC stock maintenance was from 266 to 340 g C m(-2) year(-1) for winter wheat and rotations, respectively. Additional C input did not increase the SOC pool, suggesting that arable plots had a limited ability to increase SOC. These results provide guidance for the selection of management practices to improve C sequestration