Evolution of some chemical properties of soil under influence of soil erosion and different cropping systems

英语. Since 1968, at the Agricultural Research Station of Podu- Iloaiei, Iasi County (47°12'´ N latitude, 27°16' E longitude), investigations were conducted on the influence of different crop structures and fertilizers on yield, erosion and soil fertility. The paper presented the results of investigations concerning the influence of long-term fertilization (43 years) on some chemical characteristics of Cambic Chernozem from the Moldavian Plain and on the yield of wheat and maize, placed under different crop rotations with perennial grasses and legumes. The objectives of this study was, to monitor runoff, soil loss and soil chemical properties in monocultures of wheat and corn, compared with different rotations and fallow land. The climatic conditions in the Moldavian Plain were characterized by annual mean temperature of 9.6 deg C and a mean rainfall amount, on 50 years, of 553.5 mm, of which 141.5 mm during September- December and 412.0 mm during January- August. In the last 20 years, the mean annual recorded quantity of rainfall was of 588.7 mm (100%), of which 369.5 mm (62.8%) determined water runoff and soil losses by erosion. Mean annual losses of soil by erosion, recorded in the last 20 years, in the Moldavian Plain, were of 0.161 t/ha in perennial grasses in the second growth year, 3.883 t/ha in beans, 6.369 t/ha in maize and 6.733 t/ha in sunflower. The crop structure, which determined, during 1991-2010, the diminution in mean soil losses by erosion until 1.954 t/ha/year included 20 % straw cereals (wheat), 20% annual legumes (pea), 20% row crops (maize) and 40 % perennial grasses and legumes (Alfalfa + Lolium perene). After 43 years of experience, in the pea - wheat - corn - sunflower rotation + reserve field, cultivated with legumes and perennial grasses, soil organic carbon content increased with 14.7% (2.8 C g / kg), in comparison with wheat - maize rotation.

罗马尼亚语； 摩尔多瓦语； 摩尔多瓦. Incepand cu anul 1968, la Statiunea de Cercetari Agricole Podu-Iloaiei, judetul Iasi (47°12' N latitude, 27°16' E longitude), cercetarile efectuate au urmarit influenta diferitelor structuri de culturi si a fertilizarii asupra productiei, eroziunii si fertilitatii solului. Lucrarea prezinta rezultatele cercetarilor privind influenta fertilizarii de lunga durata (43 ani) asupra unor insusiri chimice ale cernoziomului cambic din Campia Moldovei si asupra productiei la culturile de grau si porumb, amplasate in diferite rotatii cu plante de leguminoase si graminee perene. Obiectivele acestui studiu au fost monitorizarea scurgerilor de apa, pierderile de sol si ale unor proprietati chimice ale solului la monoculturile de grau si porumb, in comparatie cu diferite rotatii ale culturilor si cu terenul necultivat. Conditiile climatice din Campia Moldovei se caracterizeaza prin temperaturi medii anuale de 9.6 deg C si o cantitate medie de precipitatii, pe 50 de ani, de 553,5 mm, din care 141,5 mm in perioada septembrie-decembrie, si 412 mm in perioada ianuarie-august. In ultimii 20 de ani, cantitatea medie anuala de precipitatii inregistrata a fost de 588,7 mm (100%), din care 369,5 mm (62,8%) a determinat scurgeri de apa si sol prin eroziune. Pierderile medii anuale de sol prin eroziune, inregistrate in ultimii 20 de ani in Campia Moldovei, au fost de 0.161 t/ha la ierburile perene in anul doi de vegetatie, 3.883 t/ha la fasole, 6.369 t/ha la porumb si 6.733 t/ha la floarea-soarelui. Structura culturilor, care a determinat, in perioada 1991-2010, diminuarea pierderilor de sol prin eroziune sub 1,954 t/ha/an, a cuprins 20% cereale paioase (grau de toamna), 20% leguminoase anuale (mazare), 20% culturi prasitoare (porumb) si 40% leguminoase si graminee perene (lucerna si Lolium). Dupa 43 de ani de experimentare, in rotatia mazare _ grau _ porumb - floarea-soarelui + o sola saritoare cu leguminoase si graminee perene, continutul de carbon organic din sol a crescut, in comparatie cu rotatia grau - porumb, cu 14.7% (2.8 C g/kg).