Study On Causes Of Jujube Cracking And Methods Of Prevention In North Shaanxi Province

Jujube (Ziziphus jujuba Mill) is classified as one of "five fruits" (peach, plum, plum, apricot, jujube) and has a long history of cultivation. Jujube is a thermophilic, hi light, drought-tolerant, adaptability species known as the "iron rice bowl," and is a priority among water-saving varieties of choice fruit industry in a semi-arid hilly area of Loess Plateau. Sweet and delicious dates are not only nutrition-rich food but also can be used as medicine with its treatment, appetizers spleen and other medical functions. That is why it is called " king fruit". Jujube industry has developed rapidly in recent years. Its area and yield has gained a substantial increase, and it gradually has become farmers'channels of income. However, the artificial planting jujube trees growing naturally for a long period, with so many local cultivars and the lack of scientific cultivation of supporting measures, often caused jujube fruit cracking in the rainy seasons. Cracking caused production losses, a direct impact of the appearance of the fruit quality, marketability and greater economic losses. Cracking has become one of the important reasons which limit industrial development in China. According to a survey, jujube fruit cracking occurs every year. More than 40% of the fruit crack in 1/3 years and even more than 90% in some years. It means that it is not a good harvest. Through Jujube fruit cracking control technology and looking for ways to control jujube fruit cracking, local jujube industry development and construction of the local ecological are improved significantly. This paper, through field survey, focus on positioning, artificial rainfall experiment and testing Jujube under the conditions, laboratory testing and Jujube of quality and fruit cracking, analysis cracking crack features and the main reasons of the different local varieties of jujube fruit. The results are as follows:1,Under natural conditions, fruit cracking of different species is generally associated with rainfall time and the maturity of the jujube and the main jujube cracking reason is that Jujube's maturity and rainfall appear at the same time. Therefore, according to the local distribution of rainfall,avoiding the rainy seasons and selecting varieties of strong anti-cracking jujube is a very effective way to reduce the loss of cracking2,The results of crack resistance of Jujube are consistent in artificial rainfall and soaking experiments, so that the self-crack resistance. Jujube under the artificial rain and soaking Jujube variety of different experiments are better than those under natural conditions3,The tested cracking rates close to the 12-hour water absorption and not very relevant with the fruit quality. Water absorption of different cracking resistance of varieties in White mature period are higher than those in crisp mature period. Jujube maturity increased but water absorption capacity decreased. Water absorption in crisp mature period is lowest, the flowing is more cracking varieties and more fissile species, fissile species is the highest. Basic performance characteristics of the varieties with high water absorption are also higher of the cracking rate. Cracking rate is not the relationship between the soluble solids content of Jujube and total soluble sugar content, reducing sugar content.4,Test jujube in six varieties,in descending order,hardness of the different species are Mizao, Fengmiguanzao, Mayazao, Zanhuangdazao, Junzao, Lizao. After soaking fruit in crisp mature period,By descending order,final hardness of the different species are Lizao, Junzao, Zanhuangdazao, Mayazao, Fengmiguanzao, Mizao. Jujube fruit firmness experimental test shows Jujube fruit firmness has a negative correlation with fruit cracking. Correlation coefficient is 0.9675 **.The high hardness is also a strong fruit cracking5,At the same time different pesticides on different species have different ways of cracking. Meigaimei has the most significant effect on Junzao. Guoshubang has the most significant effect on Zanhuangdazao. Meigaimei has the most significant effect on Lizao. The Meigaimei and Yikele vitality bacteria are much better for anti-cracking according to the experiments and they are also worth promoting in production.. Under natural conditions, Meigaimei has effect on Junzao,31.3% lower than the control cracking. Guoshubang has effect on Zanhuangdazao,24.31% lower than the control cracking. Meigaimei has effect on Lizao,19.8% lower than the control cracking. Under artificial rainfall experiment, pharmacy reduce fruit cracking between 25.45% -29.42%..6,Fertilizer has great advantage to raise anti-cracking.,The most obvious effect is urea in the experimental area the cracking rate of 36.67% is lower than that of control.