Effects of exogenous calcium and soil moisture at acicula forming stage of peanut on some physiological characteristics of plants

Lack of calcium and drought frequently happen together in coastal tillage windsand soils. Pot experiments was conducted to study the effect of soil moisture on physiological characteristics of leaves and roots of peanut at the acicula forming stage and yield of peanut under different calcium levels. The results showed that the SPAD values, net photosynthetic rates, water use efficiencies and yields are improved with the increase of calcium fertilizer levels under the conditions of (553)% (LW), (753)% (MW) and (953)% (HW) of field capacity, thereinto,pod yields of peanut increased by 12.2% -19.4%; Compared with the LW and HW treatments, the pod yield at MW increased by 18.7% and 56.5% respectively. These results indicate that too high or too low soil moisture at the acicula forming stage are detrimental to the photosynthesis and formation of yield, especially under the high water content condition. The yield at the maturity is significantly and positively correlated to SPAD value, photosynthetic rate, water use efficiency of leaves and root vigor at the acicula forming stage. Both water management pattern and calcium fertilization level significantly affect the yield of peanut, but there are no significant coupling effects of the two factors. Increasing application of calcium fertilizer not only help to improve yield, but also to relieve drought in some way in tillage wind sand soils. The photosynthetic rate and yield of peanut are highest to keep about 75% of field capacity at the acicula forming stage.