Cultivation mode of walnut in hilly area for nut and timber uses

Plenty of hilly lands in China which are suitable for walnut cultivation are unreclaimed. Meanwhile, ecological restoration and economic development are also problems that these areas face. Aiming at establishing eco-economic walnut cultivation mode in hilly land, we conducted the research on efficient mode of cultivation of walnut for nut and timber uses at Luoning County, Henan Province, during 2004—2015. Precocious walnut cultivar ‘Liaoning 1' was used as the scion, and the effects of different rootstocks, i.e., seedling walnut (Juglans regia), ‘Ningyou' (J. regia), ‘Zhongningshan'(J. nigra), ‘Zhongningqi' (J. hindsii×J. regia) and ‘Zhongningkui' (J. major×J. regia) and top-grafting trunk height on mass growth, fruit yield and quality, and economic benefit were evaluated. Results showed that the elite variety of hybrid stock could significantly promote the growth, and toughen the trees and prevent senilism. ‘Zhongningqi' and ‘Zhongningkui' had a thicker stock diameter than ‘Zhongningshan', while ‘Zhongningshan' was thicker than ‘Ningyou' and the common rootstock. Investigations on the peripheral new shoot growth of the grafted trees indicated that the maximum growth appeared in ‘Zhongningqi' (24.2% higher than ‘Ningyou'), while ‘Zhongningshan' and ‘Ningyou' ranked the second. The hybrid stock could improve the nut yield and quality. ‘Zhongningqi' had a yield of 3043.5kg/ha, which was 31.4% higher than the traditional cultivation mode. The nut from hybrid stock also showed better flavor. An increase in reserved trunk height during top-grafting was beneficial to nut and timber yields, and also helpful in machinery operation and saving labor. ‘Zhongningqi' rootstock with a 1.5m trunk height showed better annual comprehensive economic benefit than the common rootstock, with a yield of 117225 yuan/ha, 1.98 times as high as the traditional cultivation mode. This study provides a new cultivation mode of walnut for nut and timber uses with high benefits in hilly areas.