When I was going around the corn areas in Southern Mindanao, I was again amazed at how our corn growers value time. They make sure that their fields have something planted on it as soon as harvesting is over for the previous crop. One field I saw the day before had some, people still picking the ears and the dried stalks were still standing. When I went back the following morning, I was surprised to see more than 10 people planting corn seeds on that same field which was probably plowed early in the day. This is remarkable for an agronomist who for many years, have been working with growers that practice crop rotation and appreciate the value of resting the soil for some time before replanting another crop. But of course, the growing environment of Mindanao is very different from that of Central Luzon and this difference dictates the kind of farming system our growers need to adopt.
Several months ago, I wrote an article about the best management practices for corn-after-corn production. A part of it was about the benefit of crop rotation in relation to stress. In relation to this, there is a so-called rotation effect which is an unexplained benefit of crop rotation that results in better yields in comparison with continuous cropping, even if the limiting factors are addresses. In a low-yielding environment, yield reductions become even greater for corn-after-corn versus rotated corn. I enumerated several possible explanations for the rotation effect but it was clear that this concept gave Central Luzon and Ilocos growers an edge over the others in the country. No wonder, they have the best quality grains and highest yields on a per hectare basis.
WHAT IS CROP ROTATION?
Several months ago, I wrote an article about the best management practices for corn-after-corn production. A part of it was about the benefit of crop rotation in relation to stress. In relation to this, there is a so-called rotation effect which is an unexplained benefit of crop rotation that results in better yields in comparison with continuous cropping, even if the limiting factors are addresses. In a low-yielding environment, yield reductions become even greater for corn-after-corn versus rotated corn. I enumerated several possible explanations for the rotation effect but it was clear that this concept gave Central Luzon and Ilocos growers an edge over the others in the country. No wonder, they have the best quality grains and highest yields on a per hectare basis.
WHAT IS CROP ROTATION?
This is a broad topic but to simply put it, crop rotation is the practice of growing different plants in succession. The basic rule is that a crop should never follow itself. Crop rotation is a farming system practiced even in ancient times and is often determined by a-region’s topography, climate types, culture, market trends and demand, among others.A classic case is the corn-rice cropping sequence being practiced in Pangasinan, Tarlac, Ilocos, and Occidental Mindoro. Generally, corn growers plant corn in the dry months starting in October and November. When the wet season arrives in the months of June and July, they shift to rice. This is specifically true among non-irrigated rice areas that have to rely on their own shallow tube wells for water during the dry months and have to be aided by rain during the wet season. If you notice, the climate and topography of these areas exert so much influence in the farming systems that farmers adopt.
In other parts of Luzon such as in Nueva Ecija, the growing trend is to insert one . corn crop in what used to be a rice-onion pattern. Still, others plant vegetables prior to planting corn then shift back to rice during the rainy months. One of the most important considerations in going into a crop rotation is the type of land or soil. Well drained or upland soils are oftentimes the most flexible in comparison to lowland ricefields traversed by communal irrigation systems.
BENEFITS OF CROP ROTATION
In other parts of Luzon such as in Nueva Ecija, the growing trend is to insert one . corn crop in what used to be a rice-onion pattern. Still, others plant vegetables prior to planting corn then shift back to rice during the rainy months. One of the most important considerations in going into a crop rotation is the type of land or soil. Well drained or upland soils are oftentimes the most flexible in comparison to lowland ricefields traversed by communal irrigation systems.
BENEFITS OF CROP ROTATION
It is ‘obvious to many farmers that crop rotation has many benefits. However, I was able to talk to some who thought it can’t work for them simply because they have no other crop of choice ‘to plant. There is no market demand for the other crop to be rotated, and the weather won’t allow them, too, plus a variety of other valid reasons. These issues are understandable and should always form part of your decision-making. Nevertheless, it will be very helpful’ to list down the things that crop rotation brings to the farm.
Soil fertility. In rice-rice, rice-corn, and especially in corn-corn farming systems, nutrients in the soil are easily used up by the crops. To produce a ton of corn grains, the field will have to supply 27 kg of nitrogen (N) per hectare, 12 kg of phosphorus (P), and 18 kg of potassium (K). Planting of other crops such as legumes after harvest of corn or rice could certainly improve soil fertility. Leguminous crops such as mungbeans are known to be helpful because of the nitrogen-fixing bacteria present in their roots, making nitrogen available in the soil before another round of corn or rice planting schedule. Farmers who plant onion, tomato, eggplant, bitter gourd, squash, and water melon use corn stubbles and rice straws as mulch to control weeds and maintain soil moisture and a good source of other nutrients upon decomposition, improving not only soil fertility but soil structure as well. In most cases, residual fertilizers coming from these alternate crops can be utilized later by deeper-rooted crops such as corn.
In the US, it is well established that corn rotated with soybeans produced the best yields as compared to corn-after-corn.
Benefits to the roots. It is suspected that the rotation effect in corn could be attributed to how the roots respond to yield-limiting stress conditions. This conclusion of a study comparing corn-after-corn with corn-after-soybeans systems. It reveals that rotated corn yields more than continuous corn. The explanation is that rotated corn has better root systems and thus, more able to withstand moisture stress. Another could be due to presence of more root insect pests (corn rootworm in North America) in. continuous corn. Soil compaction is another critical factor for the roots that can be addressed positively by crop rotation.
Control of pests and diseases. Crop rotation is one of the most practical control measures for pest and disease management. Life cycles of many insect pests, weeds, and disease-causing microorganisms are altered, disrupted and even destroyed with crop rotation practice. The presence of so many foliar and ear diseases in most parts of Mindanao and Visayas can be attributed to the fact that crop rotation is nearly impossible as corn is the only crop that can be grown in these areas and the only commodity with a sure and steady demand. Crop residues, which can hold diseases, would need to be managed very well. In contrast to Central Luzon and Ilocos, diseases are minor issues as the microorganisms that cause them do not proliferate due to alternating crop management.
Insect pests, however, are a different story. Corn and other crops may share the same pests such as pod borers in legumes and corn borers. Armyworms and cutworms in rice and vegetables can also attack corn. Such dynamics gave rise to the rapid adoption of Bt corn in the area and helped preserve the goodness of crop rotation.
Farm income.
Soil fertility. In rice-rice, rice-corn, and especially in corn-corn farming systems, nutrients in the soil are easily used up by the crops. To produce a ton of corn grains, the field will have to supply 27 kg of nitrogen (N) per hectare, 12 kg of phosphorus (P), and 18 kg of potassium (K). Planting of other crops such as legumes after harvest of corn or rice could certainly improve soil fertility. Leguminous crops such as mungbeans are known to be helpful because of the nitrogen-fixing bacteria present in their roots, making nitrogen available in the soil before another round of corn or rice planting schedule. Farmers who plant onion, tomato, eggplant, bitter gourd, squash, and water melon use corn stubbles and rice straws as mulch to control weeds and maintain soil moisture and a good source of other nutrients upon decomposition, improving not only soil fertility but soil structure as well. In most cases, residual fertilizers coming from these alternate crops can be utilized later by deeper-rooted crops such as corn.
In the US, it is well established that corn rotated with soybeans produced the best yields as compared to corn-after-corn.
Benefits to the roots. It is suspected that the rotation effect in corn could be attributed to how the roots respond to yield-limiting stress conditions. This conclusion of a study comparing corn-after-corn with corn-after-soybeans systems. It reveals that rotated corn yields more than continuous corn. The explanation is that rotated corn has better root systems and thus, more able to withstand moisture stress. Another could be due to presence of more root insect pests (corn rootworm in North America) in. continuous corn. Soil compaction is another critical factor for the roots that can be addressed positively by crop rotation.
Control of pests and diseases. Crop rotation is one of the most practical control measures for pest and disease management. Life cycles of many insect pests, weeds, and disease-causing microorganisms are altered, disrupted and even destroyed with crop rotation practice. The presence of so many foliar and ear diseases in most parts of Mindanao and Visayas can be attributed to the fact that crop rotation is nearly impossible as corn is the only crop that can be grown in these areas and the only commodity with a sure and steady demand. Crop residues, which can hold diseases, would need to be managed very well. In contrast to Central Luzon and Ilocos, diseases are minor issues as the microorganisms that cause them do not proliferate due to alternating crop management.
Insect pests, however, are a different story. Corn and other crops may share the same pests such as pod borers in legumes and corn borers. Armyworms and cutworms in rice and vegetables can also attack corn. Such dynamics gave rise to the rapid adoption of Bt corn in the area and helped preserve the goodness of crop rotation.
Farm income.
Off season vegetables and crops planted in between two main crops could command higher prices, and obviously higher farm income, which is the bottom line of any agricultural business. Although this could fit into the crop rotation scheme, crop management may be tougher than the regular planting period, but this can be compensated by better prices at harvest. Nevertheless, the so-called “palusot” crops have always been an option for farmers who don’t want to leave their fields idle and unproductive prior to the main season.
DECISION TO ROTATE CORN
DECISION TO ROTATE CORN
This article may have given a lot of reasons to practice crop rotation, and I recommend that corn growers try it. On one hand, I understand that there could be a lot of considerations at the farm level before engaging in a crop rotation scheme. From climatic conditions to topography to market demands, the decision to try crop rotation could be somewhat complex. Several times, I have engaged myself in discussing this topic with some growers and they all feel I was correct. But again, it’s a different matter when they talk of their financial security which can only be realized with their own fields. After all, it is their farm. But then again, cultural practice, such as crop rotations can have short and long term benefits..By Allan C. Nieves and Alvin Carino
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