Standard Operation Guide for Harvesting Lodged Rice with Combine Harvesters
Rice lodging is a common field disaster during the autumn harvest season, primarily caused by strong winds, heavy rainfall, field waterlogging, pest and disease infestations, and excessive panicle weight in the late growth stage. Based on actual field conditions, lodged rice is classified into four categories: slight lodging (lodging angle < 45°), moderate lodging (45° to 60°), severe lodging (> 60°), and irregular random lodging. Lodged rice features low-lying stalks and disordered plant posture. Conventional harvesting methods often lead to common issues such as uncut rice grains, grain dropping, harvester blockages, high broken rice rates, and grain entrainment, resulting in substantial yield losses and reduced harvesting efficiency. In accordance with the Technical Code for Loss Reduction of Rice Mechanized Harvesting (NY/T4963—2025) and combining practical experience of frontline agricultural machinery operators, differentiated and standardized operation methods tailored to various lodging conditions can effectively reduce harvesting losses and maximize rice yield retention in lodged fields. This article elaborates on practical mechanized harvesting technologies for lodged rice, covering machine selection, pre-harvest preparation, graded harvesting, parameter adjustment, and fault troubleshooting.
Head-feeding and half-feeding combine harvesters differ greatly in structural performance and adaptability to lodged rice fields. Selecting the right machine based on the lodging degree and growth posture of rice is the core premise of low-loss and high-efficiency harvesting.
This type of harvester boasts the best adaptability to lodged rice, especially suitable for fields with moderately and severely lodged rice in a uniform direction. It clamps and transports only the lower part of rice stalks during harvesting, maintaining complete stalk integrity. The feeding and grain lifting processes are stable, effectively avoiding grain dropping and stalk entrainment while ensuring a lower broken rice rate.
Featuring strong versatility, full-feeding harvesters are ideal for fields with slightly lodged rice, irregularly lodged rice, and dense rice stalks. For lodged rice harvesting, the machine must be equipped with professional accessories including rice lodging lifters, anti-lodging spring tines, and extended crop dividers.
1.3 Field Selection Principles: Half-feeding harvesters are preferred for neatly lodged fields with uniform and large lodging angles. Full-feeding harvesters are the first choice for complex fields with irregular and mixed-degree lodging.
Conduct on-site field surveys before formal harvesting to clarify the rice lodging degree, overall lodging direction, soil muddy condition, and field water accumulation. For waterlogged and muddy fields, drain water and dry the field in advance. The optimal harvesting period is from noon to evening on sunny days when dew is completely evaporated.
Fully inspect core components: polish dull cutter blades, check conveyor belt tension, and remove debris from threshing drums. Install targeted accessories: full-feeding harvesters must be fitted with lodging lifters and anti-lodging spring tines; half-feeding harvesters need adjustable grain lifting claws.
Properly lower the header and reel position, and reduce the harvester’s traveling speed and threshing drum speed. This reserves adjustment space for fine on-site tuning.
The key to loss-reducing harvesting of lodged rice lies in the precise matching of harvester parameters and field conditions.
4.1 Reel Debugging: Follow "lower height, forward displacement, and lower speed". Reduce overall reel height to allow spring tines to reach the bottom of stalks.
4.2 Header and Traveling Speed: Reduce working cutting width by 1/4 to 1/3 compared with upright rice. Standardized low-speed operation can reduce losses by more than 15%.
4.3 Threshing and Cleaning System: Reduce threshing drum speed and increase the drum gap. Reduce fan cleaning wind speed and slightly narrow the sieve opening.
Header Blockage Clean blocked stalks, narrow cutting width, and reduce speed before restarting.
High Grain Entrainment Loss Reduce drum speed, expand threshing gap, and adjust fan wind speed synchronously.
Severe Uncut Rice Lower the header/stubble height, fine-tune reel position, and switch to reverse harvesting routes.
The core practical principles for mechanized harvesting of lodged rice are summarized as: lift first, harvest later; low-speed stable feeding; parameter adaptation; and graded operation.
After harvesting, thoroughly clean residual grains and stalks, and conduct manual supplementary harvesting for field edge blind areas. Different from conventional upright rice harvesting, lodged rice harvesting must focus on "low loss and high cleanliness". Scientific machine selection and precise parameter tuning can control mechanized harvesting losses within the industry standard range, maximizing the yield of lodged rice fields.