Influence of some agrotechnical factors on physiological indices of potato grown on sandy soils

English. Less favorable conditions on sandy soils in southern Oltenia (Romania) limited number of species and varieties grown in the area. Drought and high temperatures in recent years have acted as forces dehydrated plants, disturbing their metabolism. Very high air temperature, relative humidity decreased to 25%, high surface temperature and lack of rainfall during the growing season, producing an imbalance of fluid balance in plante. Excessive foliar transpiration level can dehydrate plants, close osteoles and diminuted gas exchange in the process of photosynthesis. Irrigation plants can remove the stress factor action in the area, maintaining a positive fluid balance, that evaporated water is replaced by water traspiration administered by irrigation. On the sandy soils plant photosynthesis shows a depression at noon when the action is the maximum stress factors. Research early require selection of species with short growing season, to avoid atmospheric and soil drought in July and August. Potatoes meet these requirements, and research in the present study we aimed directing agrotechnical factors (variety, irrigation, fertilization) in order to obtain high yields and efficient, in economic terms.

Romanian; Moldavian; Moldovan. Conditiile mai putin favorabile de pe solurile nisipoase din sudul Olteniei limiteaza numarul speciilor si soiurilor cultivate in zona. Seceta si temperaturile ridicate din ultimii ani au actionat ca forte deshidratante asupra plantelor, perturband metabolismul acestora. Temperatura aerului foarte ridicata, umiditatea relativa a aerului scazuta la 25%, temperatura la suprafata solului ridicata si lipsa precipitatiilor in perioada de vegetatie produc un dezechilibru al bilantului hidric in plante. Transpiratia excesiva la nivel foliar poate deshidrata plantele, inchide osteolele si diminua schimbul de gaze in procesul de fotosinteza. Irigarea plantelor poate inlatura actiunea factorilor stresanti din zona, mentinand un bilant hidric pozitiv, incat apa evaporata prin traspiratie sa fie inlocuita de apa administrata prin irigare. Pe solurile nisipoase, fotosinteza plantelor inregistreaza o depresiune la amiaza, cand actiunea factorilor stresanti este maxima. Cercetarile impun selectarea unor specii extratimpurii, cu perioada de vegetatie scurta, pentru a evita seceta atmosferica si pedologica din lunile iulie-august. Cartoful indeplineste aceste cerinte si, prin cercetarile din lucrarea de fata, s-a urmarit dirijarea factorilor agrotehnici (soi, irigare, fertilizare) in scopul obtinerii unor productii ridicate si eficiente, din punct de vedere economic.