Influencing factors of seedling standing and growth of scattered planting in double cropping rice with total straw chopped incorporation

Abstract: Crop straw incorporation played an important role in soil improvement, fertilize the soil fertility, increase crop yield and quality and develop green agriculture. The research on the influencing factors of seedlings standing under the conditions of total straw chopped incorporation with mechanized harvesting can provide a theoretical basis and technical guidance for popularizing double-season rice throwing-seedling cultivation technique and realizing the reduction of rice cultivation. The experiment was conducted in Guangfu Village, Nanchang County, Jiangxi Province from 2012 to 2013 which located in the double-cropping rice production area. Based on the field experiments, the effects of total straw incorporation as well as seedling age, tillage and cultivation methods on seedling standing and growing with total straw incorporation in double-season broadcasted rice were studied. The specific design of the tests was as follows: 1) total straw incorporation test: total straw incorporation treatment and no straw incorporation treatment were set, the seedling age of both treatments was 25 days, the throwing method was point throw, and the tillage method was mechanical rotary tilling. 2) Seedling age test: Seedling age of early rice was set to 25 d and 30 d, while the late rice was set to 20 d, 25 d and 30 d. The throwing method of both treatments was point throwing, and the tillage method was mechanical rotary tilling. 3) Scattered Planting methods test: Point throwing and strew throwing were set. The seedling age of both treatments was 25 days, and the tillage method was mechanical rotary tilling. 4) Tillage methods test: Mechanical rotary tillage and mechanical deep tillage were set. The seedling age of both treatments was 25 days, the throwing method was point throwing. The results showed that, under the same conditions, total straw incorporation had little effect on seedling standing and root growth of early rice, which go against to the late rice. Seedling standing of late rice with total straw incorporation was 2 days slower than non-straw incorporation at least, while the root weight per plant was higher than non-straw incorporation after 2 days scattered planting; after 4 days scattered planting, the leaf area and yellow leaf ratio of total straw incorporation was lower than non-straw incorporation. Under the same tillage and scattered planting methods, the smaller the seedling age, the faster the seeding standing and root growth. Seedling standing of early rice of 25 d was 3 days earlier than that of 30 d at least. Seedling standing of early rice of 30 d was at 3 days longer than 25 d; the 30 days seedlings of the late rice seedlings are at least 3 days longer than 20 d and 1day longer than 25 d. Under the same tillage and seedling age conditions, the angle and proportion of seedling standing and the leaf area index with point throwing in double cropping rice was higher than strew throwing; seedling standing with point throwing was 2 days ahead to strew throwing in early rice at least, while 1 day ahead in late rice. Under the same scattered planting methods and seedling age conditions, the seedling standing speed and root growth of deep tillage were faster than rotary tillage in late rice. The leaf area index of deep tillage was higher than rotary tillage in early and late rice. In the production, while the total straw incorporation, the early rice seedling age should be 25 d, the late rice seedling age should be 20-25 d, using point throwing and deep tillage is conducive to seedling standing and growth of scattered planting.