Improving Organic Crop Production with Enhanced Biofumigation and Composting Systems

Improving Organic Crop Production with Enhanced Biofumigation and Composting Systems

Summary

The effect of mustard meal and compost application on tomato and strawberry yield, quality and disease and on nematode population, structure and dynamics in soil was studied in three field experiments at tow locations and validated in the experiment with a commercial grower. The influence of compost materials and the biofumigative effect of oil-seed radish in vegetables production were tested in an on-farm trial. It was found that positive effects of mustard meal and compost application are reproducible at the second and at the third years of the incorporation. The application of mustard meal and compost increased the yield and quality of tomato and the yield of strawberry. There was a significant protective effect of mustard meal against anthracnose of strawberry. Nematode population, its structure and dynamics in soil were significantly affected by the application of mustard meal and compost and demonstrated self-regulating capabilities that are specific to the soil and environmental conditions. Oil radish treatment in the on-farm trial presented the best values for marketable yield and fruit dry weight. More experiments with compost treatments have to be conducted in order to check on the accumulative effect of compost and oil radish on vegetable production. Webpage “Enhanced Biofumigation & Composting” (http://web.utk.edu/~tkarpine/EnhBiofum.html) was updated to present the results of the studies and to provide practical recommendations to vegetable producers on the best techniques of enhanced biofumigation and composting.

Objectives/Performance Targets

Objectives for the third year (2005) were:
1) Testing the effect of biofumigation (cover crop, mustard meal and compost application) on tomato yield and early and late blight development in the field experiments.
2) Testing the effect of different techniques of mustard meal and compost incorporation on strawberry yield, quality and disease.
3) Testing the effect of different timing and techniques of mustard meal and compost incorporation on number of weeds.
4) Testing the effect of biofumigation (cover crop, mustard meal and compost application) on nematode population, its structure and dynamics in soil.
5) Testing the influence of compost materials and the biofumigative effect of oil-seed radish in vegetables production with commercial growers.
6) Modification of the webpage for the project “Enhanced Biofumigation & Composting”

Accomplishments/Milestones

1) Testing the effect of biofumigation on tomato yield, quality and disease development was continued in two field experiments at Fletcher and Knoxville locations established in 2003 and 2004 accordingly. The results obtained this year in the experiments confirmed the main findings reported in 2004. Namely, the combined application of mustard meal and compost increases the yield and quality of tomatoes, but the effect may be achieved after 1-2 years of the application. The results of the experiments are summarized in the Table 1.

2) The effects of different techniques of mustard meal (MM) and compost incorporation on strawberry yield, quality and disease were studied in the Experiment at Knoxville Agricultural Experimental Station in 2004 and 2005. In this experiment two timings of compost incorporation were compared. First one is the incorporation of compost at the same time as MM. The second one is the incorporation of compost in 3 weeks after the MM treatments. In addition to rates of MM, two different techniques of MM application are compared. The first one is the immediate covering with plastic and the second one is just water sealing of MM treated soil. The main results of the study are presented in Figure 1.

In 2005 (the second year of the experiment), the effect of MM and compost application on strawberry yield and size was consistent with the results of the experiments with the tomato plants. Statistically significant increase in the yield is identified after application of mustard meal (2000 lb/acre) and compost (30 t/acre) if compared with the treatments 1, 2, 10, and 5 (1-control, 2,10-mustard meal 1000 and 2000 lb/acre, 5-compost 30 t). This treatment had water seal instead of immediate covering with plastic. All the treatments with the application of mustard meal showed an increase in the total strawberry yield (an average increase was 17%). Though, this effect was not statistically significant because of high variability of the yield in the experiment. The reason of the significant effect of the combined application of mustard meal and compost at the second year may be the same as in the experiments with the tomato plant.

Rating of the anthracnose (Figure 2) showed statistically significant protective effect (P<0.05) of the mustard meal incorporation at the rate 2000 lb/acre on the incidence of the disease. Treatments with the low rate of MM application (1000 lb/acre), with the compost application and with the combined application of the compost and mustard meal also indicated some protective effect. Though, it was not statistically significant. Disease incidence in the treatments of the experiment correlated with the plant vigor (R=0.50, P<0.05). Rating of this parameter also showed statistically significant effect of the mustard meal application (rate 2000 lb/acre) (Figure 8). Total strawberry yield also correlated with the plant vigor (R=0.69, P<0.05). But the correlation of the anthracnose ratings with the total strawberry yield was low (R=0.21, P>0.05)

3) The effect of mustard meal and compost application on number of weeds (Broadleaf, Grass, Onion, Nutsedge) was studied in the experiment with strawberry plants. It was found that weed ratings in some treatments with MM may increase the number of weeds. Specifically, a statistically significant increase in the number of Grass weeds was obtained in the treatment with the highest rate of MM (4000 lb/acre). A statistically significant increase in the Broadleaf weeds was in the treatments with water seal if they are compared with plastic covering. In combination it resulted in a trend to an increase of the total number of weeds in the treatments with water seal and with the highest rate of MM if compared with the control. The other treatments didn’t show difference with the control. The positive effect of mustard meal treatments on number of weeds may result from the improved soil conditions for plant growth imposed by the treatments. Total yield of strawberry and average berry’s size in the treatment 4 was also larger than in the control (Figures 1 and 2).

4) Structure of the nematodes population was studied in 2005 in postreatment soil samples and at the end of the growing season (final soil samples). The analysis included number of the following groups of nematodes: Reniform, Root-knot, Spiral, Lance, Lesion, Dagger, Stubby-root, Stunt, Ring, Soybean Cyst Nematode (SCN), Bacterial, Fungal, and Predator. The effect of mustard meal application on the number of total nematodes, bacterial feeders and fungal feeders depended on the location of the experiment. At Knoxville location, mustard meal, compost and, especially, basamid application decreased the number of the fungal-feeders and spiral nematodes and increased the number of bacterial feeders and total nematode population. In the experiment at Fletcher location, statistically significant differences between some treatments were identified only in post-treatment soil samples for total number of nematodes, bacterial feeders, and fungal feeders. The population of these groups of nematodes and total number of nematodes decreased in all treatments of the experiment if compared with the control. The most significant decrease was after mustard meal treatment and after combined application of mustard meal and compost. The results of the study indicate that the number of nematodes in soil is self-regulated. Each soil under consideration was able to maintain a steady stationary level of nematode that was a characteristic of the soil and environmental conditions. Positive or negative deviations in this parameter from the steady stationary levels imposed by the environmental conditions including treatments in the experiments were recovered with time. The Renewal rate was constant in the studied soil, independent on treatments of the experiment and influenced by only weather conditions. Considering stability of the stationary states of total nematodes in soil and their Renewal rates, we may conclude that qualitative estimation of these parameters in the soil for different weather conditions allows one to predict the dynamic changes in the nematode population after environmental perturbations.

5) The influence of compost materials and the biofumigative effect of oil-seed radish in vegetables production were tested with a commercial grower, Holden Brothers Produce, 5600 Ocean Hwy, W Shallotte, NC 28470. Test crops included squash and cantaloupe. It was found the Oil Radish treatment presented the best values for marketable yield and fruit dry weight among the treatments. More experiments with compost treatments have to be conducted in order to check on the accumulative effect of compost on vegetable production.

Impacts and Contributions/Outcomes

(1) The previous finding on the requirement of repeated applications of mustard meal and compost for the establishment of a healthy soil microenvironment was confirmed during the third year of the field experiments at Fletcher location and second year of the experiment at Knoxville location with tomato and also by the field experiment with strawberry plants at Knoxville experimental station. Mustard meal and compost application had the highest statistically significant increase in strawberry yield this year.
(2) A suppressive effect of mustard meal application on anthracnose disease was found in the field experiments with the strawberry plants.
(3) Oil Radish treatment in the on-farm trial presented the best values for marketable yield and fruit dry weight. More experiments with compost treatments have to be conducted in order to check on the accumulative effect of compost and oil radish on vegetable production.

1) A presentation of the results of the field experiment with tomato plant was made at the Fresh Market Tomato Field Day at Mountain Horticultural Crops Research Station (August 4, 2005) by Doug Sanders and Luz Reyes, Dept. Horticultural Science, NCSU; Carl Sams and Tatiana Karpinets, Univ. of Tennessee. The title of the presentation is “Mustard meal and compost as an alternative to methyl bromide”

2) Results of the experiment with strawberry plants were presented to North American Strawberry Growers Association at the North American Berry Conference in Savannah, GA (January 4-6 2006). The presentation was made by Dr. Carl Sams. The title of the presentation was “Biofumigation with composting for soil borne pests”.

3) Design of the webpage developed in 2004 was modified and content of the webpage was supplemented by results of the experiments obtained in the study, pictures of the experiments and by practical recommendations to vegetable producers. The web address is http://web.utk.edu/~tkarpine/EnhBiofum.html.

4) A database was developed to consolidate the experimental information on the effects of enhanced biofumigaiton and composting on yield and quality of tomato and strawberry plants, and on biological characteristics of soil, including number of heterotrophic bacteria, number of fungi, nematode population and structure. The database is available for download at the website of the project http://web.utk.edu/~tkarpine/Results.html.

5) Demonstration experiments were conducted with two commercial growers. They are Delvin’s farm and Holden Brothers Produce.

Collaborators: