Abstract:
To investigate the effects of sowing date and sowing amount on the yield and dry matter accumulation of direct-seeded rice in southern Henan, five sowing date treatments, namely A
1 (25 April), A
2 (5 May), A
3 (15 May), A
4 (25 May), and A
5(4 June), and five sowing rate treatments, namely B
1 (18.0 kg/hm
2), B
2 (22.5 kg/hm
2), B
3 (27.0 kg/hm
2), B
4 (31.5 kg/hm
2) and B
5 (36.0 kg/hm
2), are set up using the rice variety Fengyouxiangzhan as the experimental materials. The results show that the effects of both sowing date and sowing amount on yield reaches a very significant level, and the effects of their interaction on yield, effective panicle number, grain number per panicle and 1000-grain weight are highly significant. With the delay of sowing date, the yield of direct-seeded rice increases first and then decreases. Under the sowing dates of A
1, A
2, A
3, A
4 and A
5, the maximum yields of direct-seeded rice under A
1B
5, A
2B
3, A
3B
3, A
4B
4 and A
5B
5 treatments are 7 531.7, 9 169.5, 9 470.3, 7 961.9 and 7 462.9 kg/hm
2, respectively. Direct-seeded rice achieves the highest yields at the A
3B
3 level with a suitable effective panicle number, more grains per panicle, more dry matter accumulation and higher dry matter accumulation rate at the late growth stages.