| The research was to grasp the effect of water and fertilizer coupling on greenhouse tomato cultivated in bag at different growth stages and to achieve water-saving and fertilizer-saving, thus to realize high yield and high efficiency. With “JPCT” tomato as test material and matrix cultivated in bag, it adopted three leaves of irrigation amounts of no fertilizer as control, and the irrigation amount and fertilizer concentration were divided into three leaves(low water: LW; medium water: MW; high water: HW; low fertilizer: LF; medium fertilizer: MF; high fertilizer: HF, respectively) both at flowering period and fruiting period, respectively. Effects of water and fertilizer on growth and development, yield, quality, dry matter accumulation and allocation, nutrient uptake and distribution were analyzed. The main findings were as follows:1、Water and fertilizer had significant effects on the morphology parameters of tomato plants. With increasing of water amount and fertilizer concentration, the morphologic growth rate increased gradually, however, excessive water or fertilizer would result in leggy plants. At flowering stage, the growth rate of plant height, stem diameter and leaf area of single plant got faster with time prolonging. Meanwhile, with increasing of water amount, the plant height and leaf area increased, the stem diameter first increased and then decreased, MWMF was more conducive to promoting plant robustly. At fruiting stage, the growth rate decreased gradually, and HWHF was more suitable for the growth of plant height, leaf area, while MWHF was more in favor of the stem diameter growth. MWHF was the most robust, and MWMF took second place, there was no significant difference between them.2、Water and fertilizer affected the physiological parameters of tomato plants remarkably. Overall, as for the treatments, the chlorophyll content, net photosynthetic rate, transpiration rate, leaf water potential and root activity were higher at flowering period than that of fruiting period. Improving the amount of water and fertilizer to some extent was in favor of the enhancement of photosynthetic indexes, while excessive drought or lacking of nutrients would lead to drop of stomatal conductance and transpiration rate and so on. With increasing of water and fertilizer, the net photosynthetic rate, transpiration rate, stomatal conductance, root activity etc showed an upward trend during fruiting period. Comprehensively considered the changes of physiological indicators at flowering stage and fruiting stage, MWMF was most conducive to the growth and development of plants.3、Different degrees of effects of water and fertilizer on the yield and water use efficiency of tomato were analyzed. The yield of control was significantly lower than that of the treatments, and it was concentrated at the early and middle stages, which increased with the increasing of water. There were remarkable differences among the yield at different periods of treatments, during which, the yield at mid-harvesting stage had the highest yield of more than 50.3% of total production, while that of pre-harvesting stage took the second of accounting for about 28.5%, and the post-harvest was only about 22%. Water and fertilizer together with their interation had significant effect on the yield in each period. At pre-harvesting stage, the order of the significance among them was: water>fertilizer>the interation, however, during the mid-harvesting period and late harvesting period the order was: fertilizer>water>the interation. Meanwhile, water and fertilizer had remarkable effect on the water use efficieny, and water was more significant than fertilizer, yet the interation was not significant. The effect of water and fertilizer and their interation on yiled increased gradually with the advancing of the harvesting time, which indicated that the optimize management of fertigation at late harvesting stage was essential for the high yield and high efficiency. Comprehensively considered the yield and water use efficiency, MWMF had the higher yield and water use efficiency, therefore, the MWMF was conducive to the water-saving and fertilizer-saving production.4 、 Fruit quality was significantly affected by nutrient solution management, the harvesting time and so on. In a whole, as for the treatments, fruit quality of mid-harvest was the best and pre-harvest fruit quality took second place, while post-harvest quality was the worst. However, as for the control, the quality at the pre-harvest period was significantly better than mid-harvest. At any time, the NO3--N content increased with the decreasing of water and increased with the increasing of fertilizer concentration. At the pre-harvesting stage, soluble protein, Vc of treatment group increased first and then decreased with the increasing of fertilizer, while them decreased with the of increasing irrigation amount, and the lycopene content increased first and then decreased with the of increasing irrigation amount. Overall, the comprehensive qualities of MWMF and MWHF were the best, and the difference between them was not significant.5、Water and fertilizer had significant effects on dry matter accumulation and distribution of various organs of tomato plants at different growth stages. At flowering stage, the dry matter of leaf allocated to the highest distribution rate, followed by stems and roots, and fruit dry matter content was the lowest. What’s more, MWMF, MWHF and HWMF had the largest dry matter accumulation. The order of dry matter accumulation for various organs was: fruit> leaf> stem> root, and total dry matter accumulation of MWHF was the highest, followed by MWMF and HWMF, however, LWLF, MWLF and the control were the lowest.6、Water and fertilizer also had different degrees effects on the nutrient uptake and allocation of plant organs. Overall, at flowering stage, increasing of water and fertilizer was in favor of the nutrient uptake in different organs of plants, the order for the nutrient uptake of total plant and every organ of NPK uptake all showed the tendency of leaf> stem> root> fruit, while the total absorption at the fruiting stage showed a tread of fruit>leaf>stem>root. Fertilizer use efficiency decreased with the increasing of fertilizer amount, while it increased with increasing of water amount,because the increasing of water promoted nutrient absorption of plant.Comprehensively considered the morphology, physiology, yield, quality, water and fertilizer use efficiency of long-season tomato cultivated in organic substrate, the most suitable combination of irrigation and fertilizer was MWMF, that was: irrigation amount of single plant was 132.2L, fertilizer concentrations of seedling, flowering and fruiting stages were 1/4, 1/2, 1/2 times of the Hoagland nutrient solution, respectively. Under those conditions, it was more conductive to the growth and development of the plant, the yield of single plant and water use efficiency were 4.93 kg and 37.3kg/m3, respectively; meanwhile, the quality was better, and the fertilizer use efficiency were higher, which were N 53.25%, P2O5 58.26% and K2 O 64.74%, respectively. So it was conducive to achieve the high yield, high quality and high efficiency cultivation of greenhouse tomato. |
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