INFLUENCE OF NITROGEN AND SALINITY LEVELS ON THE FRUIT YIELD AND CHEMICAL COMPOSITION OF TOMATO IN A HYDROPONIC CULTURE

Tomato seedlings were transferred to continuously, aerated plastic containers. Treatments consisted of three nitrogen (N) levels [0, 1.5, and 3% as ammonium chloride (NH₄Cl) and ammonium phosphate (NH₄H₂PO₄) 2:1 w/w] and three salinity levels (0, 30, and 60 mM using sodium chloride (NaCl) and calcium chloride (CaCl₂)]. Results indicated significant positive and negative responses in fruits fresh weight to nitrogen and salinity treatments, respectively. Number of fruits and root length decreased at high salinity level. Phosphorus (P) content was highest in fruits and lowest in roots. Fruit P uptake decreased with salinity applications in N controls. At low salinity levels, N application mitigated the salinity detrimental effects; however, such an effect was not observed at the high salinity level. Nitrogen application significantly decreased iron, zinc, copper, and manganese concentration and uptake. Application of nitrogen and salinity levels significantly increased the citric acid content of tomato fruits. Vitamin C content of fruits was neither influenced by nitrogen nor by salinity.     

不同施肥模式对水稻生理特性、产量及其N肥农学利用率的影响

以水稻品种金优207为材料,对不施氮肥(T1)、试验区当地农民习惯氮肥用量(T2:尿素,纯N187.5 kg/hm2)和在农民习惯施氮量基础上减量配施氮肥(T3:氮减少20%,30%农民习惯用化肥+20%习惯用量的有机肥+30%习惯用量的缓释肥,纯N 150kg/hm2)3种施肥模式下水稻不同生育期的生理特性、产量及其...