Technical points for improving soil when establishing a ponkan mandarin orchard
Improving soil when establishing a ponkan mandarin orchard
The soil for most ponkan mandarin orchards needs to be improved, so that the soil layer becomes thicker, the soil texture becomes looser, aeration and granular structure improve, the soil's physical and chemical properties are enhanced, water absorption increases, and surface runoff is turned into subsurface flow, thereby conserving water, soil and fertilizer.
Orchards with different site conditions have different priorities for soil improvement: for pollution-free ponkan mandarin orchards on flat land and paddy fields, drainage ditches must be opened before soil improvement to lower the groundwater table and remove standing water. Where the plough layer is more than 0.5 m deep, trenches can be dug and beds built for planting; where the plough layer is less than 0.5 m deep, trench soil improvement should be adopted. The key to soil improvement for pollution-free ponkan mandarin orchards on hillsides is to deepen the soil layer, conserve soil and water, and increase fertility.
1. Soil improvement for paddy fields
Deep trenches with beds and trench soil improvement can be used.
(1) Deep trenches with beds: also called bed cultivation, suitable for fields (flat land) with a plough layer more than 0.5 m deep. Along the row direction, dig a drainage ditch every 9-9.3 m with a top width of 0.7-1.0 m, a bottom width of 0.2-0.3 m and a depth of 0.8-1.0 m, forming planting beds about 9 m wide, and plant two rows of ponkan mandarin on the bed surface with a plant spacing of 2-3 m.
For fields with poor drainage, along the row direction dig a drainage ditch every 4-4.3 m with a top width of 0.7-1.0 m, a bottom width of 0.2-0.3 m and a depth of 0.8-1.0 m, forming planting beds about 4 m wide, and plant one row of ponkan mandarin in the middle of the bed with a plant spacing of 2-3 m.
(2) Trench soil improvement: suitable for fields (flat land) with a plough layer less than 0.5 m deep. For trench soil improvement, dig a planting trench 1 m wide and 0.8 m deep for each planting row, then dig down another 0.2 m at the bottom of the trench (loosen only, without removing soil). For each cubic meter, use 30-60 kg (calculated on a dry weight basis) of soil improvement materials such as weeds, crop straw, branches, farmyard manure and green manure, and fill them into the trench in 3-5 layers. If conditions permit, soil and materials should be mixed and filled as much as possible. Coarse soil improvement materials should be placed in the bottom layer, fine ones in the middle layer, and each layer should be covered with 0.15-0.20 m of soil. When backfilling, mix the original 0.6-0.8 m soil with coarse materials and fill it to a depth of 0.6-0.8 m; backfill the original 0.2-0.4 m soil to a depth of 0.4-0.6 m; backfill the original 0-0.2 m topsoil to a depth of 0.2-0.4 m; backfill the original 0.4-0.6 m soil to a depth of 0.2-0.4 m. Finally, continue until the planting trench is filled and raised 0.15-0.20 m above the original ground.
2. Soil improvement for dry land
Dry sloping land is prone to erosion and has poor water-holding capacity, so planting holes (pits) are dug to improve the soil. Dig holes 0.8-1.0 m deep and 1.2-1.5 m in diameter, and make sure the planting holes do not accumulate water. Planting holes that accumulate water should be drained by blasting, by connecting holes with cracks, or by digging small drainage ditches at the bottom of the holes. When digging planting holes, place the plough-layer soil on one side and the subsoil on the other side.
The amount of organic fertilizer per cubic meter and the backfilling method for planting holes are the same as for trench soil improvement.
Orchards with different site conditions have different priorities for soil improvement: for pollution-free ponkan mandarin orchards on flat land and paddy fields, drainage ditches must be opened before soil improvement to lower the groundwater table and remove standing water. Where the plough layer is more than 0.5 m deep, trenches can be dug and beds built for planting; where the plough layer is less than 0.5 m deep, trench soil improvement should be adopted. The key to soil improvement for pollution-free ponkan mandarin orchards on hillsides is to deepen the soil layer, conserve soil and water, and increase fertility.
1. Soil improvement for paddy fields
Deep trenches with beds and trench soil improvement can be used.
(1) Deep trenches with beds: also called bed cultivation, suitable for fields (flat land) with a plough layer more than 0.5 m deep. Along the row direction, dig a drainage ditch every 9-9.3 m with a top width of 0.7-1.0 m, a bottom width of 0.2-0.3 m and a depth of 0.8-1.0 m, forming planting beds about 9 m wide, and plant two rows of ponkan mandarin on the bed surface with a plant spacing of 2-3 m.
For fields with poor drainage, along the row direction dig a drainage ditch every 4-4.3 m with a top width of 0.7-1.0 m, a bottom width of 0.2-0.3 m and a depth of 0.8-1.0 m, forming planting beds about 4 m wide, and plant one row of ponkan mandarin in the middle of the bed with a plant spacing of 2-3 m.
(2) Trench soil improvement: suitable for fields (flat land) with a plough layer less than 0.5 m deep. For trench soil improvement, dig a planting trench 1 m wide and 0.8 m deep for each planting row, then dig down another 0.2 m at the bottom of the trench (loosen only, without removing soil). For each cubic meter, use 30-60 kg (calculated on a dry weight basis) of soil improvement materials such as weeds, crop straw, branches, farmyard manure and green manure, and fill them into the trench in 3-5 layers. If conditions permit, soil and materials should be mixed and filled as much as possible. Coarse soil improvement materials should be placed in the bottom layer, fine ones in the middle layer, and each layer should be covered with 0.15-0.20 m of soil. When backfilling, mix the original 0.6-0.8 m soil with coarse materials and fill it to a depth of 0.6-0.8 m; backfill the original 0.2-0.4 m soil to a depth of 0.4-0.6 m; backfill the original 0-0.2 m topsoil to a depth of 0.2-0.4 m; backfill the original 0.4-0.6 m soil to a depth of 0.2-0.4 m. Finally, continue until the planting trench is filled and raised 0.15-0.20 m above the original ground.
2. Soil improvement for dry land
Dry sloping land is prone to erosion and has poor water-holding capacity, so planting holes (pits) are dug to improve the soil. Dig holes 0.8-1.0 m deep and 1.2-1.5 m in diameter, and make sure the planting holes do not accumulate water. Planting holes that accumulate water should be drained by blasting, by connecting holes with cracks, or by digging small drainage ditches at the bottom of the holes. When digging planting holes, place the plough-layer soil on one side and the subsoil on the other side.
The amount of organic fertilizer per cubic meter and the backfilling method for planting holes are the same as for trench soil improvement.