| In order to explore the effect of irrigation on precocious walnut growth and development and determine the scientific guidance of precocious walnut water management, ‘Lvling’ walnut trees that were planted in the spring of 2005 were used as trial materials, the effects of irrigation quantity on the growth, physiological effects, walnut yield and nut quality were studied by the method of field experiment from 2013 to 2014, There were 6 irrigation quantity treatments i.e, 0, 15, 30, 45,60 and 600 kg water per plant every time respectively. The main results were as follows:(1) The average soil water contents of irrigated 0, 15, 30, 45,60 and 600 kg water per plant every time were 17.16%, 18.11%, 19.21%, 20.30%, 21.12% and 21.88% respectively from April to September, and the relative water contents of soil were 55.08%、58.03%、61.66%、64.87%、67.78% and 70.39% respectively; of irrigated 600 kg water per plant one time was very significantly higher than those of 0,15,30,45 kg water per plant one time, that of irrigated 60 kg water per plant one time was very significantly higher than those of 0,15,30 kg water per plant one time, and that of irrigated 45 kg water per plant one time was very significantly higher than that of 0,15, kg water per plant one time.(2) The shoot lengths of irrigated 0, 15, 30, 45,60 and 600 kg water per plant every time were 13.08, 14.34, 15.20, 16.21, 16.83, 17.25 cm respectively, that of irrigated 45, 60 and 600 kg water per plant one time were significantly higher than that of irrigated 30 kg water per plant one time, and they were very significantly higher than the other 2 treatments; the leaf area indexes of irrigated 0, 15, 30, 45,60 and 600 kg water per plant every time were 3.43, 3.72, 4.09, 4.35, 4.41 and 4.66 respectively.(3) The initial flowering stage of female f lower of 0 kg water per plant every time was 1 day late than the other 5 treatments, the full blossom stage and flower fading stage of female flower of irrigated 0, 15 kg water per plant every time were 1 day late than the other 4 treatments, the fruit setting stage of 0 kg water per plant every time was 1 day late than the other 5 treatments, and there was no difference among the other phenological phases.(4) The per plant fruit numbers of irrigated 0, 15, 30, 45,60 and 600 kg water per plant every time were 120, 131, 143, 150, 154 and 166 respectively, that of irrigated 600 kg water per plant one time was significantly higher than that of irrigated 30 kg water per plant one time, and was very significantly higher than that of irrigated 0, 15 kg water per plant one time, and there had no differences with that of 0, 15 kg water per plant one time; The fruit setting rates of irrigated 0, 15, 30, 45,60 and 600 kg water per plant every time were 66.66%, 69.76%, 72.34%, 75.43%, 75.57% and 73.75% respectively, that of irrigated 60 kg water per plant every time was the highest, it was very significantly higher than that of 0 kg water per plant one time, and there had no differences with the other treatments.(5) The instantaneous maximum sap flow rate in sunny day of irrigated 0, 15, 30, 45,60 and 600 kg water per plant every time were 10.42cm·h-1, 12.60cm·h-1, 14.41cm·h-1, 16.77cm·h-1, 18.48cm·h-1 and 16.48cm·h-1 respectively, that of irrigated 60 kg water per plant every time was the highest, it was very significantly higher than those of the other treatments; Average sap flow rate in sunny day of the 6 treatments were 3.51cm·h-1, 4.10cm·h-1, 5.39cm·h-1, 6.28cm·h-1, 6.60cm·h-1 and 6.55cm·h-1 respectively, and that of irrigated 60 kg water per plant every time was the highest, it was very significantly higher or significantly higher than those of the other treatments except irrigated 45 kg water per plant every time; the instantaneous maximum sap flow rate in cloudy day of irrigated 0, 15, 30, 45,60 and 600 kg water per plant every time were 7.08cm·h-1,9.82cm·h-1,12.04cm·h-1,13.77cm·h-1,14.05cm·h-1 and 14.47cm·h-1 respectively, that of 600 kg water per plant every time was the highest, there had no difference with 45,60 kg water per plant every time, and it was very significantly higher than those of the other 3 treatments; Average sap flow rate in cloudy day of the 6 treatments were 2.37cm·h-1, 2.76cm·h-1, 3.22cm·h-1, 3.65cm·h-1, 4.04cm·h-1 and 3.72cm·h-1 respectively,that of irrigated 60 kg water per plant every time was the highest, there had no difference with irrigated 45, 600 kg water per plant every time, and it was very significantly higher than those of the other 3 treatments; Average daily leaf water potential of irrigated 0, 15, 30, 45,60 and 600 kg water per plant every time were-1.49 MPa,-1.37 MPa,-1.31 MPa,-1.27 MPa,-1.26 MPa and-1.23 MPa respectively, that of irrigated 600 kg water per plant every time was the highest, there had no difference with irrigated 45,60 kg water per plant every time, and it was very significantly higher than those of the other 3 treatments.(6) The leaf fluorescence parameters Fo of irrigated 0, 15, 30, 45,60 and 600 kg water per plant every time were 160.7, 157.9, 153.6, 152.0, 148.0 and 144.6 respectively, those of Fm were 859.0, 877.6, 908.1, 950.9, 968.3 and 974.1 respectively, those of Fv/Fm were 0.813, 0.820, 0.831, 0.840, 0.847 and 0.851 respectively, and those of φPS Ⅱof the treatments were 0.716, 0.729, 0.744, 0.750, 0.759 and 0.767 respectively; the water use efficiencies of the treatments were 1.09 mmol/mol, 1.26 mmol/mol, 1.54 mmol/mol, 1.52 mmol/mol, 1.32 mmol/mol and 1.20 mmol/mol respectively.(7) The root activities of irrigated 0, 15, 30, 45,60 and 600 kg water per plant every time were 112.37 mg·g-1·h-1FM, 121.42 mg·g-1·h-1FM, 127.31 mg·g-1·h-1FM, 135.11 mg·g-1·h-1FM, 146.02 mg·g-1·h-1FM and 139.92 mg·g-1·h-1FM respectively, and that of irrigated 60 kg water per plant every time was the highest, which was significantly higher than that of irrigated 45 kg water per plant every time, it was very significantly higher than that of irrigated 0,15,30 kg water per plant every time, and it was higher than that of irrigated 600 kg water per plant every time with no significant difference; the free proline contents of the treatments were 7.69 μg·g-1FW, 6.77 μg·g-1FW, 6.09 μg·g-1FW, 5.26 μg·g-1FW, 4.78 μg·g-1FW and 4.43 μg·g-1FW, and that of irrigated 60 kg water per plant every time was the lowest, which was significantly lower than that of irrigated 45 kg water per plant every time, it was very significantly lower than that of irrigated 0,15,30 kg water per plant every time, and it was lower than that of irrigated 600 kg water per plant every time with no significant difference.(8) The yield per plant of irrigated 0, 15, 30, 45,60 and 600 kg water per plant every time were 1.04 kg、1.19 kg、1.31 kg、1.46 kg、1.47 kg、1.48 kg respectively,and those of irrigated 45, 60, 600 kg water per plant every time were significantly higher than that of irrigated 15 kg water per plant every time, they were very significantly higher than that of irrigated 0 kg water per plant every time, and there had no significant difference with that of irrigated 15 kg water per plant every time; the kernel rate of irrigated 0, 15, 30, 45,60 and 600 kg water per plant every time were 65.56%, 66.01%, 66.21%, 66.46%, 67.84% and 68.85% respectively,and that of irrigated 600 kg water per plant every time was the highest, which was significantly higher than those of irrigated 15, 30,45 kg water per plant every time, it was very significantly higher than that of irrigated 0 kg water per plant every time, and there had no significant difference with that of irrigated 60 kg water per plant every time.(9) The kernel fat contents of irrigated 0, 15, 30, 45,60 and 600 kg water per plant every time were 66.54%, 66.69%, 67.22%, 67.74%, 67.29%, 67.98% respectively, and that of irrigated 600 kg water per plant every time was the highest, which was significantly higher than that of irrigated 0 kg water per plant every time, and there had no significant difference with that of the other treatments; the kernel total protein contents were 23.30%, 24.66%, 24.54%, 25.53%, 25.85%, 25.48% respectively, and that of irrigated 60 kg water per plant every time was the highest, which was significantly higher than that of irrigated 0 kg water per plant every time, and there had no significant difference with that of the other treatments; the kernel soluble protein contents were 36.07%, 36.36%, 36.85%, 37.38%, 35.05%, 34.72% respectively, and there were no significant differences among the treatments.(10) 45 kg ~ 60 kg irrigation water per plant every time could keep the soil relative water contents being 67.78% ~ 70.39%, shoot length being 16.21 cm ~ 16.83 cm, leaf area indexes being 4.35 ~ 4.41, fruit set rates being above 75%, root activities being higher than 135.11 mg·g-1·h-1 FM, kernel fat contents being higher than 67%, kernel total protein contents being higher than 25%, yields reaching 98.6% ~ 99.3% of the maximum yield, and the irrigation water quantity was 7.5%~10% of the conventional irrigation. So 45 kg~60 kg irrigation water per plant every time can guarantee high yield and good fruit quality, and is the suitable irrigation water quantity to guarantee high yield and good quality. |
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